The Six Killers of Night Sky Photography (and how to avoid them)

One of the best things about night photography, in general, is how forgiving it is. That is to say, you generally don’t need special weather conditions to create a really nice picture. The night and urban lights give you all you need to work with. Once it is dark the light isn’t changing so you aren’t chasing the light. Almost any night will do.

 

But if you are trying to photograph the night sky it is a completely different story. The reality is that night sky photography is very finicky. If you are going to pursue this sort of photography be ready for your opportunities to be very limited. You should also be ready for some failures.

Failure is never any fun, but it is even less so in night sky photography. You have to go to remote areas, so you will often have to drive long distances to get the shot. You will be cutting into valuable sleep time as well.  So let’s try to avoid some of those failures. In that regard, here are the six biggest problems I expect you will run into and how you might deal with them.

Night Sky Photography Killer #1: The Moon

There is nothing that will destroy your opportunities for night sky photography more than the moon. This might surprise you, but it is true. Why is that the case? Because the light coming from even a quarter moon is over 100 times more powerful than starlight. So it simply washes out the scene.

Having the moon in the sky does have its advantages. It can light up your foreground, for example.  But when it comes to photographing the stars, it is a killer.

What’s more, the moon is in the night sky for most of the month. Frankly, I wouldn’t plan a night sky outing more than about 4-5 days on either side of a new moon. Anything near a full moon is out of the question. That takes about 70% of the year out of the picture for night sky photography. As such, it is a huge limitation.

Campsite panorama of the night sky.

So how do you avoid problems with the moon? There are two ways, and for both of them, you need nothing more than a website called TimeAndDate.com. That website will tell you the moon phase, first of all. That way you can plan your night sky outing on or close to the new moon.

If you are totally unfamiliar with the moon and its phases, the new moon is when there is no moon in the sky at night. From the new moon, the moon will transition into a crescent moon, to a quarter, and then a few weeks later to a full moon (and then the process starts reversing itself). The nights around the new moon are critical because not only does that limit the illumination coming from the moon, but during a new moon phase the moon won’t even be in the night sky.

The moon travels across the sky in the daytime during the new moon phase, and across the sky at night during a full moon. The closer you are to a new moon, the less time the moon will be in the sky at all during the night.

That leads to the second way to avoid the moon, which is to take note of the times of moonrise and moonset. Again, you can get these times through TimeAndDate.com. Make sure this lines up with the other conditions you need for success (ie. times of complete darkness, weather conditions, movement of stars, etc.) which we will talk about in a second.

Killer #2: Light Pollution

You may have read that heading and said “duh.” You already know you need to be in a dark place to have any success in capturing the night sky. But you might be surprised by just how dark it needs to be. You cannot just drive outside of a city for half an hour and expect it to be dark enough to really capture a great night sky shot or the Milky Way.

What you need to do is consult the Dark Site Finder. This is the best resource I have found for avoiding light pollution. It is basically Google maps with an overlay of different colors that tell you how much light pollution a given place will have. The darker the color the better (ie the less the light pollution).

How dark do you need it to be? Really dark. Take a look at this picture:

This picture was taken in a blue area on the Dark Site finder, which is the fifth darkest area out of the 15 different levels. The light pollution you see on the bottom left of the picture was not from a big city, but rather from a small town shaded green on the map that was about 10-15 miles away.

The light pollution was not something you would see as you were shooting – everything looked totally dark to me as I was standing there. But it shows up very clearly in the shot, obviously. Make sure it is very dark where you are planning to shoot.

Killer #3: Star Movement

If you are not familiar with night sky photography, you might think you can just open up the shutter for a minute or two to allow enough light into the camera to achieve a proper exposure. But you can’t, because the stars are moving. And they are moving a lot faster than you might think. (Okay, I know this is actually due to the earth spinning – I’m not a flat-earther – but it appears as though the stars are moving!)

If you shoot the night sky with a long exposure, the stars will move while you have the shutter open. They will show up as small trails. It doesn’t look attractive and just makes the stars look blurry. Of course, you can go with it and create trails that go across the entire frame, but that is a different story entirely. What you are after here are crisp pictures of the stars in the night sky.

How long of a shutter speed can you use? On all but super-wide-angle lenses, you shouldn’t go longer than about 15 seconds. Even on super-wide-angle lenses, you shouldn’t go longer than 30 seconds. You can also use something called the Rule of 500 to determine your longest useable shutter speed. That rule says that the maximum shutter length should be 500 divided by your focal length (eg. with a 24mm lens it would be 500 / 24 or 20.8 seconds).

Because of this, you should use your widest angle, fastest lens for night sky photography. For more information on picking a lens, check out this article.

Killer #4: Lack of Foreground Element

A starry sky or Milky Way shot will provide a nice background for your picture. It is sort of like having a nice sunset. It is a great thing to have, but on its own, it won’t be enough. You also need a foreground element.

If you just head out to shoot the night sky with no real idea of where you are going, you will likely have problems. You will end up with an uninteresting foreground, and therefore uninteresting photography. The middle of the night is no time to explore and try to come up with something. Remember that where you are going will be very dark. It will be full darkness, with no moon, in a place with no light pollution. You won’t be able to see anything to come up with a foreground.

To fix this problem, you need to scout your area ahead of time. Sometimes that is possible by physically going there, but often it isn’t. When you cannot go ahead of time, you can still virtually scout the location.  Use the Street View feature in Google Maps to get you started.

Killer #5: Unforeseen Conditions Blocking Out the Stars

You probably already know that you cannot head out on a cloudy night and expect to have any chance of success at photographing the night sky. You need a clear sky, or at best partly cloudy conditions. There is no secret as to how you check this. There are a number of weather apps, so just use the one you are comfortable with.

But that isn’t the end of the issue. I have had many outings ruined when there was not a cloud in the sky. They have been ruined by things like dust clouds, smoke, and mist. These conditions aren’t as flukey as you might think. Remember you will usually be doing your night sky shots in remote places.

A desert environment is a pretty commonplace, and moderate winds kick enough dust up into the atmosphere to essentially block out the stars. If you are in a coastal environment, sea mist can do the same thing. Forest fires from hundreds of miles away can also impact your ability to get the shot.

So be sure you take a close look at conditions in your target area. It is no fun to drive for many hours and then not even pull the camera out of the bag.

Killer #6: A Boring Sky

Finally, not just any clear, moonless night will do. If you go out without understanding which stars will be in the sky when you will be shooting, you might be destined for a boring sky. If you have a strong enough foreground element, this might not matter so much. But if the night sky is the predominant subject matter, you need it to look really good.

For most people, this means including the Milky Way in your shot. That means capturing the band of stars that runs across the sky. It is best when you capture a cluster of stars at the heart of it. But the Milky Way isn’t visible all year. It isn’t visible at any time of night during about November through February. Starting in about March it will become visible just before sunrise. In June through about August, it will be visible most of the night. Starting in about September it will only be visible just after sunset. This is true no matter what hemisphere you live in.

To plan for including the most interesting stars and constellations (and, again, usually the Milky Way), just pick up one of the apps that are available for your phone. I use Star Walk 2 and I like it very much, but there are others available such as PhotoPills.

Putting It Together

Again, night sky photography is finicky. Taking steps to prepare will pay huge dividends. Because you need to be in remote areas, that means a long drive to get there. Planning will keep you from wasting a whole lot of time and effort.

But don’t wait for perfection – that never happens. Plan for the best conditions you can get, and then give it a shot. It could lead to some stunning pictures.

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