Pragmatic 101: AstroPhotography

3 January, 2021

CURRENT

Ian Norman from Lonely Speck joins John to talk about photographing the MilkyWay with just your DSLR and without spending a fortune. We cover everything from Star-Trackers, Red-light filter removal, Pollution Filters, Focussing techniques, Image stacking and lots more.

Transcript available
Welcome to Pragmatic. Pragmatic is a show about technology and contemplating the finer details and their practical application. By exploring the real-world trade-offs, we dive into how great ideas can be transformed into products and services that impact our lives. This episode is brought to you by ManyTricks, makers of helpful apps for the Mac. Visit manytricks, all one word, .com/pragmatic for more information about their amazingly useful apps. We'll talk more about them during the show. Pragmatic is supported by you, our listeners. If you'd like to support the show, you can do so via Patreon. For early release, high quality ad-free episodes, visit engineer.network/pragmatic to learn how you can help. Thank you. I'm your host, John Chichy, and today I'm joined by Ian Norman. How you doing Ian? - Great, thanks for having me, John. - Oh, it's a pleasure. I have been a long time fan of Lonely Spec and your work. And I just, I couldn't pass up an opportunity to talk to you about something that I've recently gotten involved with that you know a heck of a lot more about than I do. So I thought it might be fun just to talk about astrophotography for a little while. - Well, that's definitely one of the things I love to talk about. - Well, that's awesome. So the thing is, I think we also come at this from kind of the same premise and the same premise, but by that I mean, I started out with a normal boring camera and then I moved on to a DSLR and I went from a D5500 to a D500 and I was using it to take photos of the kids and I got a D500 because it had good low light performance and it had a really decent frame rate and it's a very good camera. And I never even thought about astrophotography at the time. I didn't even consider, it couldn't even cross my mind. I mean, I wasn't even aware of the quality of photos you could take. And then of course, well, COVID happens and everyone's in lockdown. And like, I think most people with a, well, most photographers with a camera will get out the macro lens and start taking photos of things that they're allowed to actually, you know, you can't get out and about in the world. So you take photos of anything you can around the house, take a few thousand photos of the cat. And then once you're sick of that, I looked outside and I found your site and it kind of got a little bit inspired and I thought I might have a crack at some of this because this looks like fun, but I just wanted to use what I had available to me rather than going and spending a lot of money on a whole bunch of different things. And I've just learned you can really spend a lot of money on this stuff if you really want to. Oh yeah, you can. It's photography in general is just not a cheap hobby. But I think one of the things that I like to communicate and my wife and I really like to focus on with our website Lonely Spec is that astrophotography can be within reach I suppose. It's something that you can do with a regular DSLR and it doesn't necessarily require a whole ton of fancy gear. just that that is that sort of as our starting premise. I had a handful of lenses sort of lying around and I had recently invested in a like a 200 to 500mm telephoto zoom and it's a beautiful lens but I meant to get it for sport and I thought well I might try and take a photo of the moon and then I tried a few planets and then I realized sort of the limitations of that and I thought you know what actually I'd rather take photos of the Milky Way. So The only thing I actually have specifically bought, so far anyway, for the Milky Way was an ultra-wide lens. But apart from that, I'm just trying to use what I've got. I guess, I'm just sort of curious if you could just give me a little bit of a background as to how you actually started down this path specifically. Just curious. Yeah, that's a good question. I've been around sort of space-related stuff for a long time. Both of my parents worked as computer programmers or engineers on the space shuttle program. And so, you know, it was one of those things where if there was a space launch going on, we'd watch it on TV, you know, when I was a kid. And it was just a thing. And so I had that in my childhood. And sort of like you, I discovered astrophotography when I got my first DSLR and I realized that oh, you know, you can take photos at night. And so I found myself trying to figure out how to hook up my DSLR to my telescope and realizing that, you know, this is my telescope that I had when I was like 12 and it wasn't a very good one. was not really suitable for any kind of astrophotography. But I did find in a couple of internet searches a method called piggybacking, which is basically where you attach your camera to the back of your telescope rather than shooting through the telescope. So it's just regular lens, a wide angle lens, and you mount the camera onto the telescope so that it's sort of fixed to it. And the advantage of doing that was that I could use the telescope's equatorial mount to track the stars. And the equatorial mount is basically made to rotate at the same rate as the Earth, such that you can track the stars without having them blur in your photograph. And once I did that, I was actually able to capture my first photograph of a portion of the Milky Way and that's when I just got hooked on it. It was just like I would stay up super late out in my parents' driveway and just as long as I could handle the cold and I'd run back and forth between going inside and going outside and checking my long exposure. were a lot of difficulties in trying to take a photograph with that method. I realized that there were a whole lot of other cool techniques that you could utilize to make astrophotography significantly easier. As it turns out, I probably didn't need that special equatorial mount on my telescope. That's where the hobby spawned into learning ways to make it easier, I suppose, with the equipment that I had. As a kid at the time, I didn't really have a budget to invest in a whole lot more equipment. I basically just stuck with my kit lens and my Canon DSLR. It was the original digital rebel, the 300D, which was not very good at low light. I just did what I could I could with that particular camera until I could eventually afford to upgrade to something better. Interesting. Okay. One of the things that I also learned in my just digging, diving into this is that you mentioned there the telescope that you had was not really ideally suited to astrophotography. In my naivety, I didn't realize that there's all sorts of different kinds of telescopes and each of them have different pros and cons and that's like the ones that are better for optical viewing and those optical observing, I should say, and other ones that are better for astrophotography, like they might be lighter, for example, and they could go on an equatorial mount, a few other different things. Some people say you shouldn't use Dobsonians, other people swear by them. And then, of course, as you mentioned, there's the piggyback method. The one I hadn't actually heard of that. I'd heard of a T-ring and an adapter specific for your DSLR. But the more I dug into all of these and I sort of thought to myself, to take the sort of photo I want to take of Jupiter, I think about a 16-inch Dobsonian would be nice, maybe a 20-inch. And then I started realizing, "Oh, wow, how heavy are these things?" And some people have them on caster wheels, some people you need two people to carry them. And I'm like, "Okay." And then I looked at the price tag of 15, $20,000 for a telescope, and I'm like, okay, so let's just leave telescopes out of this, I think. Yeah, and I think that's almost exactly the thinking that I had going into it too. It was sort of like, it ended up being this like huge rabbit hole that seemed like it could only really be solved by money when you really wanted to do, you know, especially like trying to take photographs of planets, that can be an expensive hobby for sure. And it's one of those things that I think you don't necessarily realize when, I guess before you really learn a whole lot about astrophotography, you don't realize that taking a photograph of a planet is actually significantly more difficult than say taking a photograph of a nebula, you know, like the Orion nebula or even, I don't know what a good example. Andromeda? Yeah, Andromeda or the Milky Way. Most of those things are actually much larger in our field of view than a planet. A planet is a tiny little speck and the Andromeda galaxy, for example, is actually larger than the moon in terms of how much of the sky that it takes up. And so that actually makes it a lot easier to photograph and it gets easier and easier the more that you zoom out and you realize that the Milky Way ends up being something that's actually fairly practical to take a photograph of with just your regular kit lens. Yeah, exactly. And like I said, I had my 500mm zoom and I did some rough calculations and I just jotted them down how many pixels across you could actually get because I've got a crop sensor. So, I've got a 750 millimetre effective focal length and I could get 45 pixels in diameter across for Jupiter, which when you think about how many pixels there are, you know, 20, 20.9 megapixel sensor, it's really not much. And you have to really use your imagination to sort of see cloud bands like and you're like, is that really a cloud? No, it's probably not. Yeah. And so, if you go and add teleconverters, which of course then creates more problems, it sort of gets to the point at which you just realize with a 2X teleconverter, which is going to have all sorts of problems with chromatic aberration, not to mention the loss of light, stopping it down to f11, you get 90 pixels across, but it'll probably be such a soft, blurry image. You may as well just- It's just not worth it. And you have to get a telescope and you've spent so much money and it's like, OK, so Planetary photography, yeah, not for me. - Right. - At least not at this point. I mean, if I win the lottery or something, I might reconsider, but not now. - Yeah, 90 pixels wide, you know, that's like, what, something like, rough calculation, I guess, would be about 6,000 pixels total in area. So you're talking about like, you know, 0.06 megapixels. So it's definitely not a whole lot of resolution when you're doing that. - No, it's terrible. And you would think that, oh, I have this 750 millimeter effective vocal length. Like surely that would be good enough. But yeah, even with Jupiter, which is like one of the visually brightest planets, it's a difficult one. So yeah, I found myself in the same sort of boat and realizing that, okay, well, there There are clearly some technical limitations to doing this stuff and some monetary limitations to being able to do this. But I just really love the idea of going out at night and capturing the night sky. And there are a lot of techniques that astronomers and real dedicated astrophotographers who are shooting through telescopes are using that didn't seem to really permeate into the world of like landscape astrophotography and they seemed like techniques that were a little bit, I don't know, convoluted or out of reach of most people. At least initially to me it seemed like there was all this talk and lingo about image stacking and darks and biases and flats and like all this terminology that I didn't - it can be sort of intimidating to get into it. Oh, for sure. But once I learned something about those techniques, I realized that they were actually simple enough to actually approach from a standpoint of regular landscape photography, that you can actually stack your landscape photos just like an astrophotographer or an astronomer would stack their photograph of Jupiter to try and get a clearer image with less noise and better sharpness. And so once I started utilizing those techniques, I knew that I had to talk about them. So that's kind of why we started Lonely Spec was to sort of like have a place where I could, almost just a place to jot down notes of what I was learning and put it in a way that was a little bit more digestible. Because it took a whole lot of learning these fancier, I guess, techniques and then distilling them down into something that I thought was fun and practical and didn't require $10,000 worth of equipment. Absolutely. And I think that there's so much really good information on LonelySpec and hence, I kept going back there and because of recommendations on there, particularly about my Tamron 1116 f2.8 DX lens, which is the one I bought specifically for Milky Way photography. And that's just one example, there's lots of really good stuff on there. So I'm glad you did put all that down there because it helped me it's helped me a lot. One of the things you mentioned is when I quickly circle back to is, you mentioned about, like Milky Way landscape photography. So for me personally, when I it sort of took me a little while with my brain and I don't know, I mean, I'm an electrical engineer, I guess I kind of, I don't know, I've struggled sometimes with the artistic things, like, am I doing art or am I not? I don't actually know sometimes, but it took me a while to get my brain around the fact that there are lots of pictures of just, of like the Milky Way or sections of the Milky Way and so on and so forth. And then I initially thought, well, we have the moon, we have Jupiter, we have deep sky objects and all sorts of different things. So, it's like the object is- It's kind of like the subject. And I suppose in photography, we have a subject and we have a background or a backdrop. And in a studio, just put up a blank sheet of paper behind your subject. Maybe, I mean, I have a studio, but I've been to a studio. And or you might use a good lens, some good bokeh to sort of like blur the background and focus in on your subjects, so the subject pops and everything. But what I've learned is that just through your work and a few others I've seen out there as well, is that the Milky Way, it's sort of- It isn't exactly your subject anymore. It's kind of- It's your backdrop and the way you- It's positioned. And if you plan your shot a certain way, then the Milky Way becomes kind of like- Quite possibly one of the most beautiful backdrops you could ever ask for. And it's sort of- It's not really the subject anymore. and that's one of the things that I've really learned to love about it. Yeah, I think that's a really good characterization of what I like about landscape astrophotography. And it's one of those things where I think, you know, as a photographer that goes out to shoot at night, you realize that the night sky ends up just being, like you said, like a backdrop. It's like one of the elements of what you're really actually trying to capture. And I think that the reason that I sort of gravitated towards landscape astrophotography rather than just pure astrophotography of just stars and nebula and stuff like that is that the subject is the Earth. The subject is this place that we're in. And that really gives you a whole lot more creative license I suppose. When you're shooting, say, like the Orion Nebula, that's basically going to turn out, like, you know, save for some different processing techniques and stuff, there's not a whole lot in the way of composition, you know, choices if you're just shooting the nebula. It's, you know, you can rotate the camera one way or another perhaps, or, you know, frame it slightly different, you know, crop it one way or the other. But there's nothing relative to it. And that can be kind of difficult to connect with, I think at least. You see these photographs from the Hubble Space Telescope that are beautiful and jaw-dropping, but it's hard to really associate what you're seeing in those photographs with what it's like to actually look up at the night sky because you can't see that with your own eyes, right? Yeah. So, that's I think what really separates the reasons why I do landscape astrophotography over pure astrophotography is because there's just so much you can do with the foreground, which is the earth. And that's actually kind of what inspired the name of the blog that we run, Lonely Spec. In this case, the Lonely Spec is the Earth. We're a lonely spec in our galaxy. It's actually based off of a Carl Sagan quote from his book, The Pale Blue Dot. Yeah, I wasn't sure about that. I thought it might have been a quote from Sagan, but it's a very apt name. And I just, yeah, I think you summarise that very well. I think in the end, I think that it connects, the backdrop connects us to the subject, which is different parts of our planet. And it just, I don't know, it's just there's something beautiful about it. And it's a unique kind of photography. And so I guess having said all of that, on a more practical sort of standpoint, I think it's probably a good idea to talk a little bit about, you sort of mentioned equatorial mounts before. And so at the moment, I personally do not have an equatorial mount. I look at them and I'm like, "Geez, I wish I had one of those." But I don't. want to, I guess, quickly talk about why you may want to get one of those and actually curious if you have one and if you use one regularly. That's a good question. I'd probably like to go in the direction of why you wouldn't need one. First and foremost, at least for your listeners, an equatorial mount is simply Basically it's a motorized camera mount or telescope mount that rotates at the sidereal rate, which is basically the same rate that the Earth rotates at. By doing that, when you mount your camera to it or your telescope to it, it perfectly tracks the motion of the stars as the Earth rotates. So it sort of rotates in the opposite direction so that over time your subject won't change. And that can be very helpful in certain situations because in the case of astrophotography we're usually taking fairly long exposures and even a 20 second exposure is enough time that you'll end up with star trails in your photograph. And that's just from the Earth rotating. So the solution to it is, or one of the solutions to it, the hardware solution to it I suppose, is an equatorial mount. And one of the problems I would say with an equatorial mount is that it requires a lot of setup and a bit of precision with that setup. And it's also an extra piece of gear that usually weighs as much or sometimes more than the camera that you're carrying. And it just adds sort of complexity to the whole process. And so I actually don't use one. I have one. I have a small star tracker basically is what it's called, which I guess may be one of the terms that they would... One of the terms that you would use for an equatorial mount is a star tracker. So I have one by a company called Move Shoot Move. And I've also owned another one called the Vixen Polari. And both of those are fairly small. They're definitely not necessarily the heaviest ones. And they're the only ones that I would personally consider because I don't like to carry around a whole lot of gear, but they have their limitations. They're not really great with super long lenses, and they're not as easy to align properly before you're shooting. And so in terms of why I would recommend not getting them other than the fact that it's just an extra piece of equipment, it's that a lot of the advantage of using a tracking mount can be sort of emulated by other techniques that don't require any kind of physical gear. And the primary technique there is image stacking. So rather than taking, say, one long five minute exposure to try and get the best possible noise out of that one exposure of the Milky Way, we would take a whole bunch of 20-second exposures, maybe take five minutes of 20-second exposures, and in that amount of time, we're still collecting the same amount of light that we would taking a five-minute exposure, but we're doing it in small steps. And so, each one of those 20 second exposures ends up having less star trailing than if you were to take that full five minute exposure. And there's some caveats to that obviously. So, your base exposures, each exposure is going to be much noisier. And so, we rely on combining those multiple exposures in software in order to improve the noise. And that's one of the things that I really love about, I guess, the day and age that we live in is that we have software to do a lot of this stuff for us. Absolutely. And so there are a whole bunch of different apps out there now, several of which are free, that allow you to take these multiple exposures and just load them into the program and it automatically realigns your images together to compensate for that motion of the Earth, and then stacks them together using a statistical method. Usually it's just a, it's taking the median value of each pixel, and that's giving you the median color, and that averages out the noise basically. And the result is a photograph that is usually as good or potentially better than if you had taken a single super long exposure using a star tracker. You're able to do that with just your regular old camera and a regular old tripod. So, that's great because I haven't actually invested in an equatorial mount, so that's a good thing. A couple of things I just wanted to discuss a bit more about the equatorial mounts is that that was one of the first disconnects I had was that people would talk about equatorial mounts. And do they mean a SkyTracker? Because so like colloquially, that's what people call them. So I had a look at the Ioptron SkyTracker and the SkyWatcher Pro. Some of them come with a Wi-Fi interface and an app now that you can sort of like adjust and so on and so forth. And it's like you say, the setup procedure looks really tedious. And you know, like you got to set the elevation based on how far away you are from the equator at that point, then you've got to align it with, if you're in the Northern Hemisphere, there's the Polaris. And if you're in the Southern Hemisphere, it's that weird collection of three, sorry, four, like a bowl sort of formation for the South Celestial Pole and all that. And if that's off, as you say, even on a long exposure, you're still going to get drift and star trailing. And the funny thing that I found is that all the blogs said, that's fine. You just add another lens with a guide scope. Right. And I'm like, okay, so here's what we're up for. We're up for a SkyTracker for $500, $600. Then you've got another camera and another guide scope. And then you've got a computer or some software. There's a device, I think, from ZWI or from ZWI. I don't have it in my notes, but that'll do some of those corrections and stuff for you. And it's like, we're getting close to $2,000 here. Ouch. Yeah, I think, I mean, I don't know, that's the sort of rabbit hole that we can find ourselves in for any genre of photography is like, what kind of gear can I get to solve this problem that I'm creating for myself? And, you know, which is, I mean, I don't know. I love it. I love the gear. I love the engineering that goes behind it. You think about what a camera is in general and it's this really cool combination of so many different, very advanced technologies that we have. Like a modern digital camera, it's a computer and it utilizes all of these really great things and it's just combined it all together into this like really sweet package that just creates a fun thing to do. So why wouldn't we want to try and get some more gear that gives us that same sort of feeling? But at the end of the day, when you really think about what are you trying to do with your photography and the real joy comes out of the actual creation of the image. And if you're spending all of your time fiddling around with the setup of your equatorial mount and trying to figure out how off of the actual celestial pole that you are, even though you have it pointed at Polaris, you end up losing sight of the actual objective of the night, which was actually to capture the Milky Way or whatever else you wanted to photograph. And so, yeah, I think that's why I ended up kind of settling more for the simpler approach to astrophotography. And it ends up, I think, being the better way to approach this genre of photography because it doesn't have that equipment hurdle, you know. I mean, there are certain types of photography that you just, you need the equipment for I don't think that astrophotography is the one where the equipment is where you should start. I really think it's the technique. That's awesome. Again, I'm now doubly glad that I haven't invested in one. The other observation that I had just from my digging through this in various forums and reading, well, lots of forums and lots of opinions on it is that if you're doing something because the star trailing is obviously, well, I say obviously, it is worse the more you zoom. So if you've got a nice wide angle lens, then you can have 15, 20 second exposures without too much trailing, depending on how wide you've got it. But if you try and zoom in, zooming into a deep sky object, repositioning that constantly after you take an exposure and you can't have an exposure more than one or two seconds long without it blurring, I can see why you'd want an equatorial mount, but for what we're talking about here today, there's just no, it doesn't seem to be a very good reason to do it. Yeah, that's exactly, you know, that sums it up perfectly. If you're shooting on a wide-angle lens, you really don't need one. And it really isn't until you start to exceed about 100mm in focal length, at least with a typical, you know, APS-C or full-frame camera. shorter than that, you can still utilize the stacking method with just a regular old tripod and end up with a result that, you know, is potentially just as satisfactory as if you had spent all that extra money on a Star Tracker and tried to shoot, you know, using that extra equipment. So, yeah, that sums it up well. lens, don't really need a star tracker, long lens more than 100mm, then that's when you should probably start thinking about it. And so that's why I usually suggest for people just getting into astrophotography, start with your wide-angle lens, your 18-55mm kit lens or whatever your camera came with, zoomed all the way out, actually tends to be a really great place to start, at least to learn the process of capturing the night sky, learning about the exposure and just being comfortable being outside in the dark with your camera and taking those exposures. It's much easier on simpler gear. So you also talked about image stacking. So let's just dive into that a little bit. So you mentioned there are a bunch of different terminologies and it might be worth just quickly just touching on each of them to make sure I'm on the same page. So, we've got bias frames, dark frames, flat frames, and are they really called light frames or frame frames? I think light frames is a good way to characterize it. The actual frames, the actual photo. Yeah, the actual, yeah, the ones that contain the light. The frame frames. Yeah. Right. Yes. Yeah, so light frames are just our regular old exposures of the night sky. The next ones to talk about I think are dark frames and those ones are basically capturing the same exposure using the same settings but with your lens cap on or the body cap on your camera. And what that does is it allows us to capture the noise profile of the camera sensor. Basically it captures the pixels, the noisy pixels of the noisy pixels that sort of remain consistent between each of your photographs. And every sensor has a different sort of profile of noise. And so by capturing those, and usually we capture a stack of those as well, we can then subtract those in software. And so some of the stacking software available, I use one called Starry Landscape Stacker, which is available for Mac OS. And there's another one very, very similar to it called Sequater, sort of like Equator but with an S in front of it. And Sequater is available for Windows. And then there's a couple others out there. But those are the two sort of easy ones to use for landscape astrophotography. Those programs will take those dark frames and automatically recognize them and then subtract that noise profile that they recorded from your light frames. So it's a really great way to further reduce the noise in your photographs. And the interesting thing about dark frames is that most cameras actually have a built-in dark frame recording and subtracting function. So a lot of cameras will actually do this automatically. And if you go into your camera's menu and you search for a setting called "long exposure noise reduction, or sometimes it's just truncated to long exposure NR. That's a setting which will do exactly that same process. Once you take a photograph, usually exceeding a certain threshold, say one second long, the camera will automatically detect, "Oh, this photographer is taking a long exposure. Let's go ahead and take a dark frame after we finish the light exposure so that we can and subtract it later for that extra noise reduction. And so a lot of times, photographers will go out their first time shooting astrophotography. And long exposure noise reduction is usually enabled by default on most cameras. And so they'll take a 30-second exposure. And then their camera will finish the exposure. And then it'll sit there, and it'll say busy. And it'll just say busy, busy, busy for another 30 seconds. And a lot of photographers are like, what the heck is going on? Why is my camera so slow? Or how come it's taking a full minute to take just a 30 second exposure? And that's because the camera's actually recording an extra dark frame so that it can subtract it. And that setting is one that I usually recommend people turn off just because it can waste a lot of time. It ends up turning half your night into waiting for the dark frame to record when you could be repositioning for a better composition or checking your results so that you can adjust your focus or something like that. So I usually recommend disabling it so that you can take your own dark frames at the end of the night and use those later in software. So yeah, lights and darks, those are the first most important, I suppose, types of frames when it comes to talking about stacking for astrophotography. The other two, flats and bias frames, I would say if you're just approaching astrophotography you don't really need to worry about too much. A flat frame is simply another recording of an element of a photograph that we sort of don't want in the image, just like the noise for the dark frames. So a flat frame records all of the sort of brightness aberrations that a lens might have, and those could be things like dust specks on the sensor or vignetting, basically light fall off on the edge of the image. So most lenses, especially when you're shooting wide open at the low f-numbers, tend to have a fair amount of vignetting. So you get these kind of dark corners on your image, you know, where the light just sort of gradually falls off. And so taking a flat frame allows you to sort of record that and then compensate for it later. And just like your, just like the dark frames, how I said that cameras have built in dark frame subtraction, many cameras now have essentially built-in flat frames, which is the sort of built-in lens correction settings in your DSLR. Those tend to work fairly well, but if you're really trying to sort of stretch your images in post-processing, if you're trying to add a lot of contrast, and maybe you're dealing with photographs that were taken with a fair amount of light pollution and you're trying to sort of adjust those out using Photoshop or Lightroom and you're stretching the image a lot to try and get the most out of it, sometimes the profiles that are built into the camera won't necessarily be the most accurate in terms of how it's compensating for the vignetting of the lens. And so, in order to take a flat frame, a lot of astrophotographers will put some sort of translucent card in front of their lens, maybe a piece of translucent acrylic, or some people even just use a piece of fabric, and they'll shoot a photograph using a bright light source through that diffuse piece of fabric or, you know, diffuse material so that they can sort of record what a neutral gray image looks like through their lens. And that'll give them that perfect profile to compensate with later in post-processing. I personally actually don't take flat frames. It's something that I think for landscape astrophotography is not super important. A lot of the vignetting that you end up dealing with in that sort of situation isn't as detrimental to the final results and can actually be beneficial too just from a sort of artistic standpoint. And so, you know, yeah, flat frames end up being one that I would say are a lower priority if you're just getting into astrophotography. And then the last one, a bias frame, is basically just a really short exposure made on your camera in order to sort of capture a second type of noise profile for your sensor. And so that one is also, I would say, kind of lower on the priority for somebody just getting started on in astrophotography. OK, so those I think are they the ones that are very, very short exposures, like one eight thousandth of a second and you just take a whole bunch of them in in darkness, I think it is. Yeah. Is that am I thinking about it with no, with no- With, yeah, with the body cap on. I'm just trying to remember. Yeah, with the body cap on or with the lens cap on. Yeah, just really, really short exposures. And basically, you know, that differing from a regular dark frame, basically it's capturing like two different types of noise that our sensors end up generating. The dark frames end up focusing more on the fixed pattern noise, which is the noise that is very consistent between each photograph. Every sensor is sort of imperfect and we end up having like artifacts of the electronics not being completely perfect in there. And any given camera will always have one or two hot pixels and maybe a little slightly brighter area on one part of the sensor. And that's what the dark frames focus on removing. And then the bias frames end up focusing on removing the other types of noise, basically like the shot noise, the things that are a little bit more random with each shot, if that makes any sense. I think that's a simple explanation of it. Yeah, it's one of the more difficult ones to explain. I've sort of struggled getting my head around it. But I was very interested to know that, for example, when you're taking your photos, that you don't actually do those ones. Because I hear different opinions, well, I read different opinions about them and how important they are or aren't. So, you know, it sounds very much like, for the sorts of photography we're talking about, it's probably not much benefit in doing them. So I'm happy to leave them out, I guess. Yeah, I think, you know, kind of going with the same theme of what we were talking about of sort of trying to keep things simple and approachable, you know, well, actually, I mean, honestly, to sum it up, like the, when it comes to stacking and all these different types of frames that you can take, very often I will just shoot regular old light frames and not even worry about anything else. Dark frames are useful, but sometimes the conditions or your equipment are usually good enough that you don't really need to add that extra complexity in there. So if you want to just start out and learn these stacking techniques, my suggestion to most people would actually be to just focus on your regular old exposures and getting those dialed in first before you add the extra element of, "Okay, I've learned how to stack my light frames together, but maybe I'm seeing a little bit more noise or I'm having some problems with hot pixels. Then let's focus on the next outing. I'm going to record a whole bunch of dark frames and subtract that." And then you're like, "Okay, well, now I'm set there, but maybe I'm having some vignetting." So then you can add in your flat frames. So. - Cool. Before I go any further, I'd like to talk to you about the sponsor for this episode. And that's ManyTricks, makers of helpful apps for the Mac. Whose apps do, well, you guessed it, ManyTricks. There's so much to talk about for each app they make. So we're gonna touch on some highlights for six of them. Usher 2, the return of the classic Usher. But now it's a full 64-bit app that works well with Catalina and Mac OS 11 Big Sur. So what is Usher? It's an amazing, powerful media management and playback app that can see your movies that you have in TV, music, and the Photos app, or any library location that you'd prefer on your Mac. It can organize them for you if you like. You can create advanced playlists and sorting criteria, and you can even edit their information all from within Usher. Not only that, to celebrate the return of Usher, you can grab the Usher 2 beta from the link in the show notes, and there's a special pre-sale for it as well. Check it out. Time Sync. Track your time spent in apps or activities on your Mac the simple and easy way with Time Sync. You can pool your apps by common activities, create custom trackers for non-Mac activities, and its simple but powerful reporting features show you exactly where your time went so you can plan better and stay focused. Resolutionator. It's so simple. A drop-down menu from the menu bar and you can change the resolution of whatever display you like that's currently connected to your Mac. The best part though, you can even set your resolution to fit more pixels than are actually there. It's very handy when you're stuck on your laptop and you need more screen real estate. Which, you should think about which is a supercharger for your command tab app switcher. If you've got three or four documents open at once in any one app, then which is beautifully simple pop-up lets you pick exactly the one you're looking for. You can switch between tabs as well as apps and app windows with horizontal, vertical or menu bar switching panels. With text search for switching, you can show the front most app in the menu bar icon with full touch bar support and much, much more. Name Mangler. You've got a whole bunch of files to rename quickly, efficiently and in large numbers. Well, Name Mangler can help. It's designed for stage renaming sequences with powerful rejects pattern matching. Recent additions include a group by feature when making a sequence and title case conversions can now keep their existing formatting or convert them all to lowercase based on word length. The best part is it shows you the result as you go. So if you mess anything up just revert back to where you started and try again. Moom makes it easy to move any of your windows to whatever screen positions you want, halves, corners, edges, fractions of the screen and then you can even save and recall your favourite window arrangements with a special auto-arrange feature when you disconnect or reconnect an external display. It has full touch bar support and keyboard integration with Adobe's apps and it also works perfectly on an iPad operating in sidecar mode and has a sharper hexagonic look in Big Sur. It's the first app I load on a new Mac because, well, it's just awesome. Now that's just 6 of their great apps, that's about half of them and they all work on the latest version of Mac OS, Big Sur. All of these apps have free trials that you can easily download from ManyTricks, AllOneWord.com/pragmatic and you can easily try them out before you buy them. They're all available from the website or through the Mac App Store. However, if you visit that URL, you can take advantage of a special discount off their very helpful apps exclusively for Engineered Network listeners. Simply use ENGINEER25, that's ENGINEER, the word and 25, the numbers in the discount code box in the shopping cart to receive 25% off. Now this offer is only available to Engineered Network listeners for a limited time, so take advantage of it while you can. Thank you to ManyTricks once again for sponsoring the Engineered Network. But something else on the DSLR just specifically that just occurred to me we hadn't really just touched on and it's pretty quick. Having talked about all the frames and everything and I mean you can actually buy special astronomy specific cameras but if we want to use our DSLR one of the things I didn't realize until I started digging into this was that most DSLRs have got a red light filter built into them, which as I said initially, I didn't realize. And I'm just curious, I mean, my camera's got one and I know that you can actually pay to get them modified. And I think there might even be cameras you can buy, DSLRs that don't have it fitted. I'm not sure about that. So what have you- Right, yeah. Yeah, so pretty much every camera that you buy has what they call, there's a few different terminologies used for it. They have a filter called the UV/IR cut filter, or sometimes it's called the hot mirror, and that filter sits right on top of this camera sensor. So when you look into the inside of your camera body, if you were to take an exposure with your DSLR and actually see the sensor when the mirror and the shutter are open, what you're looking at is a piece of glass on top of your sensor. So the reason that your sensor looks shiny, basically, is that first thing that you're seeing there before the actual pixels of the sensor is the hot mirror filter. And that filters out everything outside of the visible spectrum. So it filters out ultraviolet light and it also filters out infrared light. And that's very helpful for daytime photography because when we shoot a photograph we want it to look like regular life, right? We want to see in our photographs an image that looks like what our eyes can see. And since our eyes can't see infrared, most camera manufacturers want to filter that out because it can be sort of detrimental. It can cause sort of like weird color shifts in certain materials. Some materials reflect a lot of infrared light and that'll make certain clothes and stuff actually look visually off in terms of their color. So the easier thing for a camera manufacturer to do is to just filter that out. And the problem with filtering out infrared light is that, at least for astrophotography, is that many of the things that we see in the night sky actually emit a whole ton of infrared light. And so it can be beneficial to try and capture that extra light. Okay, so the camera, the DSLR that you use, have you had that filter removed or have you not? No, actually I haven't. Although I'm sort of contemplating on doing a conversion on one of my camera bodies. So I shoot on the Sony A7S. I have the original Mark I version of it, which when it first came out was known specifically for its low light capability. Sony marketed the S version of the A7 as being the sensitivity version of the camera, you know, for having high sensitivity for specifically for shooting in low light. And it still has, you know, the regular UV IR cut filter in it. But I recently went out shooting with a camera called the Canon EOS RA. And it's a version of their EOS R mirrorless camera that has that hot mirror or that UV cut sensor, or I'm sorry, UV-IR cut filter removed, and it's just sort of replaced by, I think, an alternate filter that allows much more infrared light to pass through. And the results that I got from that camera were convincing enough to me in terms of what I was able to capture in relatively difficult conditions for me to consider wanting to modify my current camera. But it's definitely not something that's super necessary. One of the things to take home about those cameras is that they're only going to give you a benefit with very specific objects in the night sky. Because they're only amplifying the light gathered by these, what they call like red emission nebula. nebula that transmits what they call hydrogen alpha light, which is a very specific band of light in the infrared spectrum. And it's fairly common in terms of objects that we have in the night sky, but it's not going to make your camera suddenly a million times better at capturing the Milky Way or anything. transmits plenty of visible light so we can still take successful photos without that. Cool. Alright, because I know that you... I don't know, I've read that there are certain places you can actually ship your DSLR to and they'll do the modification. Some people, I think I even found a how-to guide for one model of camera and it wasn't mine, but where they showed you how you can disassemble the camera and actually take it off and I think you'd be a very brave person doing it yourself. Yeah, I've contemplated doing that myself. I am a mechanical engineer and I love taking things apart, but looking through some of the guides that these other photographers have published online of what it takes to disassemble your camera to remove that filter makes me not even want to consider it because it is a lot of parts. Cameras are, like modern digital cameras, are very complex things. And I think the room for error and maybe not necessarily always having the right tools is reason enough that you might want to just send it to a professional service to do. Some of the ones in the United States are LifePixel and Kolari Vision, and then I think also Spencer's Camera. And they all do those conversions for $200 to $300 US dollars. I think that that's cheap enough that it would be worth going that route instead of trying to do it yourself. Sure. I mean, but if you did it either way, either yourself or even paid one of those companies you suggested to do it, I imagine you're saying goodbye to any warranty that may be left on your camera if you do this. Yes, definitely. Yeah, I think they all have a disclaimer like right on their site every time you look up, you know, like this will void your warranty. So, that's what you'd be giving up, of course. Okay, that's fine. Yeah. Yeah. So, alright, awesome. So, thank you for that. One of the other things just want to quickly touch on and then I'll sort of move on to light pollution specifically, but it seems like a simple thing and that's a tripod. And I actually had a very old aluminium or as you may say, aluminium tripod, and it had a a quick release head on it. So, a pan tilt head, but it was integrated into the tripod. So, it was so cheap you couldn't separate the tripod head from the legs, right? So, you get the picture. I have no idea what the load carrying capacity was. So, in a moment of, shall I say, electrical engineer, okay, you're a mechanical engineer, you would have told me to not do what I did. I, however, thought that'll be fine. And I put my 200, 500 millimetre lens plus my D500 on this very cheap tripod. It was the middle of the night. I was trying to take a photo of Jupiter using the tripod. And in the dark, it literally just fell off. And I know. and I actually caught it about an inch or two before it hit the tiles. So I, that was just in the dark, just blind luck. I have no idea how I caught it, but I did. So in so doing, I broke my tripod head because now I can't trust 'cause it's all wobbly. So one time when I was desperate to take a photo of just the Milky Way with my new Tokina lens, I just got out, as any good engineer does, a whole bunch of duct tape. and I just strapped it together. But, you know, that's not a viable long-term solution. So I've ordered as part of the Black Friday sales that are going on at the moment, I grabbed a new set of an actual set of legs and an actual decent tilt, a pan tilt head that can handle, you know, five kilos in the pan tilt head and 14 kilos of the legs, which should be more than enough. But I'm just curious if you had any other any specific suggestions for a tripod or a tripod head for this sort of photography? - Yeah, so tripods are one of those things that I think, it's like the piece of equipment that photographers hate to be excited about, right? We can all be excited about lenses and camera bodies because those things are kind of, you know, sexy and they, you know, they're the things that you associate with actually producing the picture, right? - Oh, for sure. - And tripods are always thrown to the wayside. So a lot of people will go out and get the cheapest tripod they can. And yeah, that can be potentially detrimental. Maybe it'll work just fine, but there are definitely some things to think about when choosing a tripod and things that will just make your life so much easier. And you'll be more confident. You won't have to have that situation where, yeah, maybe something will break or something won't be quite right and that'll either ruin your shot or potentially ruin your equipment. So beyond just load capacity, which is an easy number for tripod manufacturers to publish, the other things to think about are stiffness. And that's actually the most important element to what a tripod actually needs to do. It's easy to make a metal device or carbon fiber device to support a camera that weighs five pounds or something like that. That's super easy to do. The more difficult thing to do from a design standpoint is to make that thing stiff in a way that with all the vibrations of handling and even the camera shutter, that it's not going to sort of vibrate at that natural frequency that's going to ruin your shot. And there's actually a website that I really love. There's an engineer, I think he's here in the US, he has a blog called the Center, excuse me. He has a blog called The Center Column. If you look this up, The Center Column is basically just a giant ranking, like ranked list of all of the kind of top tripods in terms of their stiffness to weight ratio, basically. He actually… Well, I'm just looking at the site now and I like some of the titles, White Writings and Meaningless. Right. Yeah. Yeah, David. I don't know David's last name but David of the Center Column. Great website. Going there, it's been just sort of really enlightening in terms of things to think about when you're approaching purchasing of a tripod. I like that he puts different priorities, so you can sort of sort the tripod lists on his website by the priorities that you might have. So maybe you would prioritize the weight of the tripod over necessarily the stiffness. So you can sort of see how they stack up relative to other tripods within a certain weight class. So he has sort of like a travel tripod class and then a full-size tripod class of rankings. And he does some pretty cool tests. Some basically, there's a couple different types of stiffness that he tests. One of them is, and the most important one, and where most tripods sort of fail at is in torsional stiffness. So that's torsion about the vertical axis. So he does these really involved tests using accelerometers and weights and basically tests the stiffness of these tripods. And he quantifies all of it there so you can see. It's a very, very helpful website. So that's one of the first places that I go in terms of looking for a tripod and sort of seeing what he's found in terms of what are the best tripods out there. And he's tried to test a lot of the more mainstream affordable tripods and then he's also tested a lot of the really expensive, $1,000 get-so systems. So, you can sort of see how certain things stack up. Cool. I kind of wish I had known about that site before I went and bought mine actually. It hasn't arrived yet. I'm not sure I'm going to be returning it or not, but I'm going to read that. Thank you for that. It's really lots of good stuff there. Just having a quick look at it now while you were talking. Thank you. Very good. Beyond that, I like to think about a tripod in terms of its weight primarily. Beyond finding one that's like, "Okay, I can do the weight rating of my gear, I can support that, and it's fairly stiff," at least according to David of the center column. The other thing that I really like to think about is, do I want to carry this thing around with me, you know, up a mountainside or, you know, in the dark. And there is a definite limit to where your gear ends up being more of a detriment if it's too heavy. You know, you can have the stiffest, highest weight rated tripod, but that tripod's probably going to be too heavy. So it's one of those things where you have to sort of find the happy medium and find one that you're willing to carry with you. And I always like to say if it's one that you're not willing to bring with you on every photography outing because it's potentially too big, then it's not the right tripod. It should always be the piece of gear that you will always want to have with you just like you'd have like to have your favorite lens or your favorite camera body, you should always have your favorite tripod with you. So, that's something that you should think about when you're approaching the purchase of a tripod. Awesome. All right, cool. So, I'd like to just shift gears slightly and before we get to light pollution, I also thought we should talk about focus and I don't mean necessarily of topic, I meant the focus on the lens. And I had this- I did all this research and learned about this focusing tool called a Batanov mask, which I kind of actually, I think it's very cool that this is only a relatively recent thing. Apparently, Pavel Batanov came up with this in 2005, so it's really only 15 years old as an idea. I kind of like that. And he was an amateur photographer. And it shows three lines that cross at a center point when you're in perfect focus. And the thing that I was reading about this was that it's supposed to only really work because it blocks a lot of light, at least the traditional large filters, the solid filters and all the little slots in them, sort of a funny pattern, and it blocks a lot of the light. And I read that it's only going to work at 100mm effective focal length or greater. So, it couldn't work on wide angle lenses. But then when I was looking through your site, you have the SharpStar. Yeah. So, can you tell me a little bit about that? Because it's very cool. I mean, exactly the thinking that you went through about, you know, oh, you can only use this Batnav mask at 100 millimeters or greater. I was like, I thought the same thing. And I was like, "Man, this would be a really great tool if we could somehow use it on our regular camera lenses." And I tried making my own sort of traditional Baton Neuve mask using laser-etched, dark plastic sheeting. And I came up with the original SharpStar design, which was essentially a very, very fine-lined Baton Neuve mask. And that worked fairly well for lenses down to about 35mm, but it depended on the aperture. It had to be a fast lens. And so, using some of the funds that I was able to get from selling this first version of the Sharp Star, that helped us develop the Sharp Star II, which is designed specifically for use on wider angle lenses, much shorter focal lengths. So it can go down to about 14 millimeters. And it gives you that really nice star pattern of a typical Baton Neuf mask. And it just makes focusing that much simpler. It gives you sort of a visual positive affirmation of sort of critical focus. And that's a tool that I'm definitely proud of, in terms of developing. And we've sold thousands of them around the world to probably about 60 different countries around the world. - Because I mean, I can't find anything quite like it because the table that you have on the website talks about as you're going down like 16 millimeters, millimeters, 15, down 11 and so on. And then the different F-stops, so aperture sizes. So it shows you where it can work and where it's sort of borderline and then where it just won't work. And I haven't found anything else that goes anywhere near as low in terms of wide angle and relative aperture as the SharpStar 2. So that's pretty impressive. - Yeah, it's definitely, It took a lot of trial and error in developing it. And really, honestly, the harder thing about developing it was just figuring out the manufacturing method for it, which luckily turned out to be pretty simple. But yeah, I don't know, it's a tool that I would definitely recommend for people if they're struggling with focus. And if your listeners are interested in checking it out and they're getting into astrophotography and they want to try it out. We do have a 100% guarantee on it. That's basically to sort of help in a situation where maybe your camera and lens combination aren't super happy with the Sharp Star II. Certain cameras have darker live view feeds or certain lenses, especially with lower light, Especially with lower F numbers, or I'm sorry, with higher F numbers, we'll potentially have more issues like being able to see the diffraction pattern of the SharpStar II. So we want to make sure that anybody who receives it is at least satisfied with how it's working. So that's why we put that guarantee on there. And so no questions asked, we'll do a return or refund for anybody who does have an issue with it. you know, most of the time it works out really great and people tend to really love that tool. Cool, so this thing, it's essentially just a square piece of glass or perspex, I'm not sure what the material is, I assume glass. Yeah, we use an optical acrylic. Oh, okay, so optical acrylic. And it slides into a standard box mount, I'm not sure what the terminology is, I'm sorry. Yeah, it's a square filter holder. Basically, it's a square filter system. A lot of photographers like using neutral density filters, either graduated or really dark neutral density filters so that they can do long exposures during the daytime. That usually requires one of these square filter holders, which is basically just a little bracket that fits on the front of your lens, and it has a slot for a filter. And usually these filters are either 100 by 100 millimeters square, and usually about 2 millimeters thick. And so our SharpStar II filter is designed to slot into one of those standard filter holders. This is a million different brands of those holder systems, but they all are sort of cross-compatible as long as they're similarly sized. Awesome. Well, I haven't invested in one yet, but I'm eyeing one off. Don't worry. It's on my wish list. I have to talk about light pollution. When we first started emailing, I sort of mentioned, "Oh, hey, I'm in a Bordel 4 area." It's one of those things that I just sort of, "Oh, yeah, the Bordel scale, right?" It's just like, that's astronomy talk. I'm now speaking astronomy talk and I had the light pollution map app on my phone and I had a look at it and said, yep, you're in a Bortle 4 area. I didn't actually dig into the detail of how a Bortle 4 or 321 or the scale from 1 to 9. I didn't actually dig into what each of those definitions was until I was just preparing the last of the show notes for this episode. And I was quite surprised to find that kind of like the Batanoff mask, the Bortle scale was only like published by John E. Bortle in 2001. So, it's not even a 20-year-old thing. So, it's also relatively recent. And it seems like it's very much- I mean, some people say, "Oh, it's a quantitative scale." But if you look at some of the definitions about what you can see at different levels, I'm not entirely sure quantitative is probably the right way of describing it. I don't know. What do you think? I think the Bortle scale is kind of a difficult... When you think about the conditions that you actually encounter at night, the Bortle scale tries to put a single number on a specific location for how the light pollution will affect your seeing capability. One of the things that you'll find at night is that when you're out shooting in a suburban area or even a rural area, light pollution is not like an even distribution across the sky. It's very often worse in one direction, usually looking toward a city. If there's a city within 100 miles, it's going to emit light that reflects off the atmosphere. So the Bortle scale is kind of, I would say, just kind of a rough measure of how good the overall scene will be. But it's not necessarily going to be the end all super precise quantization of the amount of light pollution that's in that area. And I actually find that some of the tools that I use, they don't even necessarily specifically use a Bortle scale. They'll use the same sort of rainbow colors where the best seeing is illustrated as being very, very dark with a black or gray color and then the worst seeing is highlighted in bright orange or red or even white. And sometimes they'll use a little bit more graduations in the scale than just the one through nine of the Bortle scale. And at the end of the day, when you're planning an astrophotography shoot, you're pretty much just going to look for the darkest spot that you can get to within a reasonable amount of time of your home or whatnot. And so, I don't necessarily think it's like any reason to choose one place over another if you're looking at the difference between like a Bortle 4 versus a Bortle 5, because other things like the direction that you're facing during the night or the time of year or even the weather conditions can affect how that light pollution is actually showing up in your shots. Yeah, I'm glad you pointed that out because it's something that occurred to me when I looked at it. If I draw a cross on a map and stand on it and I look straight up, the map may say according to all the light pollution guide, like you're in a Bordel Four Zone, but the fact is that if you turn south, that's the direction of Brisbane, the largest city near me, and there's this... Well, it is a nice glow unless you're trying to take astrophotos, but other than that, you turn around to the north and there's practically nothing. It's not like pitch black, but it certainly is much, much darker. So, it'd be okay in turn facing northwards. So, northwards, you're looking at the equivalent of a Bordel 3, maybe a Bordel 2. But if you turn south, then maybe that's the Bordel 4. So, it's like there's no- Like an X on a map doesn't really tell the story. And that was sort of the conclusion I'd reached as well. Yeah. Yeah. And if I really wanted to look at the map, and of course, I've just I've done this because I, you for the hell of it. And I've said, "Well, where's the nearest thing on the map that says this is a Bordal 3 area?" So, that's 45 minutes drive from where I live. A Bordal 2 area is about one and a half hours from where I live, and a Bordal 1 is about three and a half hours drive. So, it's a decent hike. I mean, you could do it if you were keen. And I suspect at some point I'm going to, but for the moment, I have not yet. I'm just going to stick to my backyard for a bit. Yeah. I'd usually suggest for people who really want to step up their astrophotography when they've gotten comfortable maybe shooting in their suburban neighborhood. They're like, "Okay, I understand at least how my camera operates at night. I've gotten down my focus technique and I've figured out the exposure that I like using." The next step really is to go out to a nice dark place. depending on where you live in the world, that's going to be potentially one of the bigger challenges of astrophotography is going out and finding that nice dark spot. Where I am in Chicago, there isn't a whole lot around here that gets much better than about Bortle 4. It's very difficult to get better than that. Even the areas on a map that may be sort of marked as Bordel 3 or 4, their adjacency to much brighter areas is much more detrimental than you would think. There tends to be just a really strong glow on the horizon around pretty much anywhere that you are in Illinois, no matter how low the Bordel rating is. Some of the best shooting in the United States ends up being in the western states where Most cities are very far apart and there's lots of big deserts and unpopulated areas and those are the places that I would recommend people go. Find your state or your country's national parks, state parks, any sort of public land or camping area out in the middle of nowhere. the outback, I guess is what you would say, right? Yes. Out in the sticks and the outback. Yeah. And that really is, I think that's the hardest, that's the biggest challenge with astrophotography beyond just simple technique is going out and actually going to a place that's nice and dark. Deserts tend to be a great place to go if you can just because of the other factors that that brings to night photography. Having moisture in the air can always be potentially detrimental, you know, I mean, especially if it clouds over. But yeah, deserts will give you the best sort of seeing conditions for being able to photograph the night sky. So I usually think that that's the thing that's going to make the biggest difference in terms of the result that you get in your astrophotography is actually going to a really dark place. That's a funny way you phrase that. Okay, so here's the thing. I absolutely agree. I have not done that myself and the nearest desert for me is a decent hike. It's probably more like a five or six hours drive. Actually, it's probably even further than that, but contrary to popular belief, Australia is not entirely desert, but never mind that. It's okay. So, let's assume, and this is one of the things that of course I've sort of started digging into some more, and that is, let's assume you can't get in the car because of limited range, limited budget, because obviously the further you go, then you've got to stay there if you don't mind camping. That's one thing if you're allowed to camp there. So, a whole bunch of other little barriers. So, let's say you're stuck at home and you're in a Bottle 4 or Bottle 5 zone. I've been reading up on light pollution filters. So, the thing that I thought was interesting when I started digging into this is that there's a lot of talk about low pressure sodium and particularly filtering out 589 nanometer light. But one of the things that I really wanted to ask you was, I mean, my understanding is, because you know, being an electrical engineer, I know that LPS lights are being phased out, they're being replaced by... Absolutely. Yeah. I mean, LED lights are just, they are more efficient, they're more reliable. And of course, they're a lot more directive. So, I mean, you're always going to get light bouncing and refracting off of, you know, different objects in the city, but I mean, how effective are light pollution filters really? And is it just, are they just for low pressure sodium for that wavelength or are there other kinds you can get? They're becoming increasingly less effective because of LEDs, basically. Right. That's the gist of it. I was afraid you'd say that. So, sodium lamps are still around. I mean, it's one of those things that's definitely changing and I think probably eventually may not be solvable, I guess, with a light pollution filter. Ultimately, a light pollution filter never really, you know, it never really makes a night and day difference, right? it's not going to suddenly turn off all the light pollution. There's always going to be something there because these lamps don't emit a perfect band of light and there's always some other source of light that's going to end up in your shot. But at the end of the day, a light pollution filter can make a difference enough to give you a little bit of edge in terms of contrast in your photographs. It's just like that one extra little tool that you could add to your kit. I would definitely say that they're not magically going to make your photographs better, but it's one of those things that it's sort of like taking the time to take some dark frames or something to reduce the noise from your sensor. It's like adding that extra little bit to your shot. And I wouldn't necessarily recommend a light pollution filter for somebody just starting out. But if you are finding that you're enjoying shooting in your backyard or something like that and you want to be able to filter out some light, if you are seeing an orange glow in your shots. If you're actually seeing kind of like a muddy looking sky in your shots and you want to filter that out, then that's where a light pollution filter will help. But it's sort of situational. I found that some of the places that we've been shooting fairly often have changed over the years. It used to be that one of our favorite places in California called Trona Pinnacles, which is this area with these kind of rock spire formations, used to have like a really strong sodium vapor lamp, orange glow that would cast itself both on the rock formations that you were shooting at, as well as you would see it in the background of most of the shots when facing south towards the Milky Way. And it gave it like a certain characteristic. And over the years, each year that orange glow has become whiter and whiter just because of municipalities changing their street lamps to LEDs. There is something to be said though about the possibility that a lot of these LEDs might potentially be also replaced with LEDs that are filtered into that sort of same wavelength as the sodium lamps. A lot of people are finding that they don't like the really white looking light from LED lamps. They can be a little bit more disruptive at night for a number of different reasons. But I don't know. Sorry, yeah, you're right. I think I was reading an article a few years ago about the wavelengths of those LED lights being more disruptive to sleep patterns and interfering with nocturnal animals more so than the low-pressure sodiums, if I remember correctly. Right. Yeah. That's going along with a lot of the things that we're seeing. Even our everyday gadgets, like our phone screens now automatically adjust its white balance in order to become warmer looking, which is actually like a... it'll become more yellow in the evening, right? Like iPhones do this and some Android phones now do this. And one of the reasons that manufacturers are doing that is sort of to make your screen a little less disruptive to your sleep patterns. And that ends up translating exactly the same way to these LED lights that they're using for street lamps now. And yeah, I don't even, I don't know, looking at a bright white light, you know, like a daytime temperature colored light at night really is kind of disruptive. It doesn't feel right, I guess, you know, just from a real internal, you know, I don't know. Maybe it has something to do with how humans lived off of being able to have a fire at night to keep ourselves alive in the cold and having that warm glow at night is so much more reassuring than having this really bright white light source. Yeah, I think there might be something to that. I mean, if you think about it, there's the fire and the campfire idea and then of course that progressed to candles, which is the same kind of wavelengths. And then suddenly we're bringing in modern technology and we've got light. So they're completely different color spectrum that in some respects mimics more of what the sun would produce. And our bodies are just like, well, hang on a minute, is it day? Is it night? And now I'm confused. So it's kind of, I think there is something to that. And some people might be more affected than others. But just from the photography perspective, I'm just curious, do you ever use a light pollution filter anymore? Or have you sort of given up on them? No, I do. I still use them, especially when I'm shooting in a rural, or I'm sorry, in a suburban area, or anywhere where the direction that I'm facing is expected to have some sort of light dome, either from a city or a nearby town. I do like to use a light pollution filter to sort of have that little extra edge in the shot. it definitely can reduce the sort of, I don't know, sort of like a haze that you would get over your photos. Sure. Oh, yeah. And it gives you a little bit more contrast. But I find myself shooting without them every once in a while too. If I'm in a very dark place, then oftentimes I won't shoot with one. Actually that's because I don't want to necessarily filter out light that can potentially be advantageous to my shot. And sometimes that's a little bit of light falling on the foreground. You know, when you're shooting these wide angle landscape astrophotos, the foreground is actually the more difficult thing to capture. It can be, especially when you're in a very dark area. If you want something other than just a silhouette of a tree and you want to actually have some visible detail in the foreground, you actually kind of want a little bit of light. And luckily, shooting at night, even in the darkest places like, you know, Bordel 1 areas, there's always a little bit of glow in the sky. And that usually makes a big difference on what you can see in the foreground, especially if you're using a technique like stacking where you're able to combine multiple exposures together to reduce the potential noise problems that you would have in a really dark foreground. And that's one of the things that I think I like most about going to these really dark places is actually realizing that you can see pretty well even in a Bortle 1 area at night. It's amazing how bright the sky actually is and how you can actually see things in the foreground, once your eyes adjust, even just the brightness of the sky itself, not necessarily the stars itself, but the sky will actually light up the foreground. And that's actually a cool concept, which I didn't know if we were going to come to, and that's the idea of air glow. Airglow is sort of, you could think of it as nature's light pollution. It's a really interesting phenomenon. It's basically a glow in the sky caused by several different factors. It could be atomic oxygen or other molecules in the upper atmosphere releasing their energy from the day. It's basically the de-excitation of their electrons from residual energy from the day, solar energy from the day, sort of blasting off a photon. It can usually be kind of a strange green glow. I think atomic oxygen is green when it emits light. You'll get these kind of weird green cloud-like patterns in your shot. It can be a really neat phenomenon to have in your photographs. That's a thing that happens everywhere around the world. It doesn't matter where you are. Assuming you're in a dark enough place, you can usually capture airglow. It can sometimes look a little bit like shooting the aurora, although much dimmer in terms of brightness. That's kind of a neat thing to discover, going out to a shooting in a really dark place. So that will be happening up in the stratospheric level of the atmosphere, up at higher altitudes I imagine, is that right? Yeah, I believe so. I think it's really, really high altitude. It's one of those things that you only really get to see in a super dark place. It's the underlying reason why the night sky is never pure black between the stars when we're out in a very, very dark area. There's always kind of a glow to it and it's actually just the atmosphere itself emitting its own light, which is kind of cool. >> Tom: That is very cool. That's something I wasn't aware of. That's interesting. One of the things you also brought up just briefly was the lighting of foreground subjects. And that is something I just wanted to touch on was the idea of light painting, which when I first heard that, it sort of conjures a very interesting image in your imagination before you actually think it through as to what it might mean. So I'm just curious, do you do your light painting and how do you do that exactly? I do it very rarely, mostly because I like to, I personally like to capture a, I like to capture a night photograph that looks like night. Right. That has sort of that dark, you know, I don't know, atmosphere to it. And as soon as you add in an artificial light source, there's always something that's a little bit off. Sure. - Sure. - All right, so there's this one more thing I really wanted to talk about and I probably should have talked about it a little bit earlier, was just the lens selection for Milky Way photography and the balance between how wide is extra wide. You know, you were saying, for example, I started extolling the virtues of a kit lens, which, you know, if you've got a full frame camera and you've got an 18 millimeter on the wide end, then that's probably pretty good. For me with a DX, 18mm just wasn't enough, so I needed to go down lower. But obviously had I had a full frame, it probably would have been fine. Then again, you could also say, "Well look, I've got a 35mm f1.8, so it's a pretty fast lens, and I could just do panorama stitching, and I could do two or three different positions and stitch them together to try and get better resolution without having to buy another lens or a wider lens. I mean, I could have done the same thing on my camera, for example. So I guess I'm just curious what your thoughts are. I mean, would you lean more towards an ultra wide or do you prefer a panorama stitching? So as I've gotten more and more experience over the years with astrophotography, I've tended to shift towards longer and longer lenses. And I know this is probably going to end up in me buying a telescope at one point. But I usually, I would recommend a similar progression I suppose in somebody getting into astrophotography. Start with a wide angle. Just in terms of how complex it is to shoot with it, a wide angle lens makes things easy. The Milky Way is a really big thing, right? It's all around us at night and it takes up a really large portion of the sky when it's visible, when you can actually see the galactic plane. Using a wide-angle lens will be the easiest way to capture that. That said, oftentimes people will find that maybe they don't have the widest lens, like Like an 18mm on a DX or APS-C camera is 28mm equivalent. That's a wide angle, but it's not a huge field of view. Sometimes the cheapest next upgrade that photographers will get for their camera is a nifty 50, like a 50mm 1.8. Those lenses tend to be really affordable. Some of them you can get for less than $100. They're fast. They give you that really large aperture, a really low F number. They tend to be very sharp. One of the problems with a 50mm 1.8 is on an APS-C camera, that's a really narrow field of view. It's more of a portrait lens, you know, that you would take photos, you know, in a studio with. And I wouldn't necessarily suggest that people shy away from using a lens like that. And panorama stitching is definitely the technique that you can utilize to take really successful, or really great photographs of the Milky Way using one of these longer lenses, like a 50 millimeter. I now have found that my favorite lens to shoot the Milky Way on is actually a 105 millimeter lens. I have a Sigma 105 millimeter F1.4. So it's a very fast, low F number, long lens. I'm shooting that on a full-frame camera. And one of the problems with shooting with that is that you don't really capture a whole lot of the night sky. So, I have to shoot these like really large multi-row panoramas, basically shooting a big mosaic of photographs in order to capture that really wide-angle field of view that I want. And ultimately, I guess that's what I think people should think about is how much work do you want to put into creating these photographs? If you want to just be able to go out and take a few snapshots and come out with a Milky Way photo with fairly little effort, then shooting on a wide-angle lens is going to be the much easier path to take. Shoot with your 18mm or, like in your case, a wide-angle zoom that can go down to 11mm And that's going to be the easiest approach. So that's usually what I suggest for people to do. So most of the tutorials that we've written on LonelySpec tend to recommend the kit lens or a wide angle zoom. Something that has that really large field of view because that's going to be the easiest way to capture that really big Milky Way in the sky. I was going to say in Australia, where in the southern hemisphere, at certain times of the year, the Milky Way galactic center, the really bright core of our galaxy, ends up being really high overhead in the night sky in the southern hemisphere. That's another reason to shoot on a wide angle lens, is because you want to capture both that foreground and the Milky Way, but the Milky Way is up at higher than 45 degrees. probably going to want a fairly wide angle lens. Yeah, to that point, yeah, I mean, lucky me living in the Southern Hemisphere for that at least. But I mean, it's also not quite Milky Way season for me at the moment. I mean, if I get up at two in the morning, I'll get it as it comes up in the east. But I'm sort of waiting. I think the next really good chance will be in January and hopefully my new tripod gets here by then. I'm just not game to do any shooting with a dodgy tripod at the moment. But just getting back to the panorama stitching, you mentioned some other software, but previously that you were using for light stacking. Is that the same software you use for the panoramas or is that done separately? No, that's done separately. So the stacking software that I had mentioned, Starry Landscape Stacker and Sequater, both of those pieces of software are made almost specifically for the landscape astrophoto with a wide-angle lens. where you have a foreground in there and you have the sky. And between, you know, your shots of the sky tends to move, you know, from the earth's rotation. So, it's made specifically to process that specific situation. But for the panorama stitching, I actually use a dedicated panorama stitching software called PT GUI, which stands for Panorama Tools GUI, or Panorama Tools Graphic User Interface. And that's a mouthful, but it's a really great panorama stitching software. It's made specifically for stitching together large numbers of images into a panorama. I can do full 360s if that's what you're looking for. And it's the only piece of software that I've been able to find that can handle really, really large panoramas. So since I like shooting on 100 millimeter, I'll often find that my panoramas have anywhere between say 40 individual frames to up to 250 individual frames. And that's a lot of data to process. And, you know, there's a lot of things to think about when you're trying to stitch those together, a lot of problems. For one, over the course of shooting, the sky is rotating, or the sky is moving relative to the Earth from the Earth's rotation. So you can have misalignments along the horizon. And all kinds of other little factors go into trying to properly align and then blend all of these images together. And PTGui is definitely the best piece of software for doing that. There are a few others out there potentially worth checking out. There's Microsoft ICE, which I think stands for Imaging Composite Editor or something like that. I think that one's free. There was a really great piece of software that is no longer being produced called AutoPano Giga. But the company that was behind AutoPano Giga ended up getting purchased by GoPro. GoPro eventually phased out the development of that piece of software, which is a little bit disappointing. I don't think you can buy that piece of software anymore. It was very, very good. But right now, the PTGui is the best tool for doing those types of panorama stitches. Awesome. Okay. The only other thing that I just wanted to quickly mention, just to quickly review on it, we've talked about a whole bunch of different software. wishing to recap all of those but for me personally you know I obviously I use PhotoPills all the time particularly so I can get a good idea of when the next time the Milky Way is going to be at the right angle at the right time and the galactic core is going to be at maximum brightness and so on and which is something that now I've got a decent well I say a decent lens I could do it with what I've got currently got but I want to use the ultra wide so and I'm waiting for my new tripod so I love PhotoPills I use the light pollution map but there's a few different apps out there for that. Did you have a preference or a pick for anything for that sort of purpose? I just use a website called Dark Site Finder. Sure. Yeah. And yeah, that's the one that I usually go to. There's a whole bunch of different ones out there. I mean, if you just Google light pollution map, you can find them. That's the one I use. It has a, you know, graduations similar to the Bordel scale on it. They're a little bit finer, I guess, in terms of graduation. But it works basically the same. And yeah, that's often a first step is sort of like, "Okay, let's look at the light pollution map. Where is a dark place near me?" And then when you find a rough area of like, "Okay, it's kind of dark over in this direction. Now where is a place that I'm actually allowed to be at night or that I can camp at?" And you go from there. The only other app I just wanted to quickly mention, I use Sky Guide, which is just, you know, the cheat sheet for wherever all the constellations are. And whilst I'm gradually getting better at learning where everything is, it's one of those things that when I was younger, I, you know, I was in scouts for a little while. And so I sort of know some of the basics and some of the constellations, but it's been just getting back into astronomy and now learning astrophotography. I'm learning the night sky a bit better, But to be fair, I think it's fantastic that there are apps out there like Starwalk, Skywalk, there's a whole bunch of different ones, all similar names. And you put on augmented reality, hold the phone up to the sky and it'll just show you the backdrop. It's pretty accurate and it really helps. Absolutely amazing tools. Sky Guide is probably the one that I would recommend for people on iPhone. It definitely has the best, you know, like, photo-realistic representation in the Milky Way. But yeah, there are other apps too. I use one for Android called Stellarium. And Stellarium's, it's all right. It's pretty good. You know, definitely useful. And it has the sort of AR pointing where you can, you know, figure out where everything is and where it will be at any given time of night. If I remember correctly, I think Stellarium is also a cross-platform application. I think you can get it for the Mac and for Windows as a desktop application, if I remember correctly. Yeah, that's true. Yeah, you can. Even Linux, actually, it's available for Linux. Yeah, that is very cool. Well, Ian, I have to say, I think we could probably keep going, but we should probably stop at some point. There's so much to learn and so many ways you can improve. And I'm so grateful for your time and your insight into this. If you wanna talk more about this, you can reach me on the Fediverse at chigi@engineered.space, on Twitter @johnchigi or on Word, or the network @engineered_net. I'd personally like to thank ManyTricks for sponsoring the Engineered Network. Once again, if you're looking for some Mac software that can do ManyTricks, remember to specifically visit this URL. ManyTricks, alloneword.com/pragmatic for more information about their amazingly useful apps. If you're enjoying Pragmatic and want to support the show, you can by supporting our sponsor or via Patreon at patreon.com/johnchidjee, alloneword. A big thank you to all of our patrons, a special thank you to our silver producers, Mitch Bilger, John Whitlow, Kevin Koch, Oliver Steele, Lesley, Law Chan, Hafthor, and Shane O'Neill, and an extra special thank you to our gold producer known only as R. Patron rewards include a named thank you on the website, a named thank you at the end of episodes, access to raw detailed show notes, as well as ad-free, high quality releases of every episode. So if you'd like to contribute something, anything at all, there's lots of great rewards. And beyond that, it's all really, really appreciated. If you'd like to get in touch with Ian, what's the best way for them to get in touch with you, mate? - First and foremost, I guess I'd recommend just visiting our website, LonelySpec.com. That's the website that my wife Diana and I built and have been improving and adding on to over the years. There's tons of different tutorials and we talk about gear a lot on there, which I love, and tools that you can use to help you with your night photography. So LonelySpec.com and there you'll find links to our Instagram and YouTube as well. It's instagram.com/inorman for Ian Norman. And then YouTube-wise, it's youtube.com/lonelyspeck. And yeah, so that's probably the best way to find me. And we have a contact form on the website. If you ever have a question about astrophotography, feel free to just shoot us an email and we'll do our best to respond. Fantastic. I've learned so much from Lonely Spec and also from your time today. I really do appreciate the opportunity to talk to you and just wanted to say a special thank you to our patrons and an extra special thank you to Ian for your time. I really, really appreciate it. Thank you so much. Yeah, thank you so much, John. This was a lot of fun. [outro music] [MUSIC PLAYING] [Music] (upbeat music) [MUSIC PLAYING] [Music] ♪ ♪ ♪ ♪ (dramatic music) (dramatic music) (upbeat music) (upbeat music) (electronic music) (dramatic music) you
Duration 1 hour, 48 minutes and 52 seconds Direct Download
Episode Sponsor:

Show Notes

Links of Potential Interest:

Helpful Apps:

Light Pollution and Filters:

John’s Camera Gear:

Ian’s Camera Gear:

Star Tracking:

DSLR Conversion Services USA:

Image Stacking Software: (Wide-Angle)

Big Image Panorama Stitching:


Episode Gold Producer: 'r'.
Episode Silver Producers: Mitch Biegler, John Whitlow, Kevin Koch, Oliver Steele, Lesley Law Chan, Hafthor and Shane O'Neill.
Premium supporters have access to ad-free, early released episodes with a full back-catalogues of previous episodes
SUPPORT PRAGMATIC PATREON APPLE PODCASTS PAYPAL ME
STREAMING VALUE SUPPORT FOUNTAIN PODVERSE BREEZ PODFRIEND
CONTACT FEEDBACK REDDIT FEDIVERSE TWITTER FACEBOOK
LISTEN RSS PODFRIEND APPLE PODCASTS SPOTIFY GOOGLE PODCASTS INSTAGRAM STITCHER IHEART RADIO TUNEIN RADIO CASTBOX FM OVERCAST POCKETCASTS CASTRO GAANA JIOSAAVN AMAZON

People


Ian Norman

Ian Norman

Ian is a Mechanical Engineer from the United States that turned in his job at SpaceX in 2013 to pursue his passion for AstroPhotography. Developer of the SharpStar 2 Bhatonv Mask and the creator and editor of LonelySpeck, Ian has been taking photos of the MilkyWay for nearly a decade.

John Chidgey

John Chidgey

John is an Electrical, Instrumentation and Control Systems Engineer, software developer, podcaster, vocal actor and runs TechDistortion and the Engineered Network. John is a Chartered Professional Engineer in both Electrical Engineering and Information, Telecommunications and Electronics Engineering (ITEE) and a semi-regular conference speaker.

John has produced and appeared on many podcasts including Pragmatic and Causality and is available for hire for Vocal Acting or advertising. He has experience and interest in HMI Design, Alarm Management, Cyber-security and Root Cause Analysis.

You can find him on the Fediverse and on Twitter.