Understanding the Night Sky
No matter what you shoot as a photographer, it's really important to understand your subject. A bird photographer's going to be a lot more successful in the field if he understands flight patterns, habitat, migration patterns, and so on, food sources. The same thing applies to someone who is interested in capturing astro landscape photography. In this case, our key subject, what we're really trying to capture is often the Milky Way, and so let's start with that. When I first started into this style of photography, I really didn't understand the night sky, even though I'd been looking at it for most of my life. When I first really got into it, it was in the winter, and during my first foray, I was really disappointed that I couldn't find the Milky Way. I set up my camera, took a couple of shots, and here it was, the end of January, shooting around a quarter to 9:00 at night, and I could see a cloud of stars kinda tracing its way through the sky, but no real impressive core, and I didn't...
understand why that was. Well, and one of the key things is that there are many seasonal changes that happen during the course of the year, and those changes are mainly because of the tilt of the Earth's axis. And so, the reason I was completely blanked on those winter shots was because Milky Way's below the horizon. At least the core of the Milky Way is. Fast forward to spring, and suddenly the Milky Way is beginning to appear. The core will start to rise, but you gotta get up real early in the morning to see it. If we move a little farther into the year, now we hit early summer, we can now begin seeing a more typical orientation, where we're getting a part of the arc showing in our frame. If you are interested in shooting panoramas, then you wanna do that as early in the season as you can. So we've got this arc early in the year. Later, we get a more typical orientation where you can still see part of the arc. It's going over your head, but it's just a lot harder to photograph, let's say in June, than it is in April. Right now, we're at the end of July, and if I wanted to capture an actual panorama of the entire arc, it'd be almost impossible. It would require several rows of shots in order to get them, because now, this late in the season, the Milky Way is becoming a more vertical orientation, which, you know, can also look great, but it might impact the way you compose the shot, so the seasonal changes are a really important thing to understand when it comes to trying to photograph the Milky Way. Another thing is just understanding the transition from day to night. Seems pretty basic, right, to go from sunset to night, but there is this large transition zone. Astronomers have terms for it, we're entering the twilight zone, but there are actually three degrees of twilight. Once the sun has set, we're into something called civil twilight. The sun has just gone below the horizon, and it's still illuminating any of the clouds that are up in the atmosphere. As a landscape photographer, that's kind of my favorite time to actually go shooting. Wait a little longer and we end up into nautical twilight, so now we're into about 45 minutes, an hour after the sun has set. Stars are beginning to show up, and that's why it's called nautical twilight. Sailors used to actually use that as sort of the perfect time to navigate their ships. They could see some stars coming out, but also still see some land, 'cause we're into the blue hour. Wait a little longer, and we're into astronomical twilight, and each of these time periods last roughly a half an hour. The sun is dropping by about six degrees for each of these, and night, what astronomers call night, doesn't really officially begin until the sun is 18 degrees below the horizon, and that's when the sky's as dark as it's going to get, and for us, of course, that's when we wanna be shooting. I'm gonna go out and scout during some of the other periods of time, during the golden hour, and during civil twilight, I'll be setting up my shots, or thinking about what I wanna shoot next. I'll start taking my test shots during astronomical twilight, because now I can probably see the Milky Way, but it's going to be a very washed out Milky Way at this point, 'cause it's still not quite dark enough, and it's going to be a little more difficult to actually capture the nice, true colors of evening, 'cause everything is gonna sort of have a blue wash to it, so once you understand sort of the basics of the Milky Way, and the transition between night and day, there are a lot of tools that are available that can help you with your planning. There are some web-based sites that I like to use, and definitely some on my phone that can be helpful in the field. When it comes to trying to plan my shots around the rise and set of the Moon, I'm using timeanddate.com. It's got a nice calendar that in one screen, I can quickly see when is the New Moon falling, when is the Moon rising and setting for other days that will allow me the biggest window to shoot? When it comes to my mobile apps, I've downloaded a few that I really like. By far, my favorite is PhotoPills. So lemme just open that up, all right? It allows you to do so many different things that are well beyond just astro photography, but I can hit the Planner, I can figure out when the Sun is setting. So let's say for tonight, golden hour is at 7:13. The Sun is setting at 7:48 tonight, blue hour is at 8:00, and I can keep scrolling through these until I hit that astronomical twilight, and night officially begins at 9:24, and that's when the galactic center of the Milky Way will be visible. Probably the best tool here is the Planner, and so here I can scroll through the timeframe, and you can see the lines are moving as the Sun is moving. The orange line is the Sun moving through, here we come to the golden hour, all right, the screen just turned kinda gold, so that's sorta the ideal landscape shooting time. Now we're heading into twilight, and night time, and so this arc that you see here is the Milky Way, and so it's rising in the south, and progressing across the sky, so PhotoPills is absolutely amazing as a planning tool. Let's get outta that one. All of this is for naught if you don't have nice, clear skies, so another app that I am regularly using is Clear Outside. So it's just loading that up for this location, here we go. And you can see that for, what I'm looking at here is the total cloud cover. As I scroll through the times, you can see that by the time we get into evening, right, that we are beginning to get some serious cloud cover, so shooting may be difficult, and we can continue on looking days ahead to find out just how things are looking in terms of our clear skies. One other one that I like to use is Stellarium. I don't use it as often, but if you watch this really quickly, it's gonna fast forward through the day until we're at night, and now I can see that sort of the twilight has occurred at 8:36, and I can sort of move my sky around to see how things are looking, and I can change the time as well. So those are some of the apps that I am using. Often, it's just a matter of personal knowledge, but there are some really great tools out there that you can download, and many of them are free.