lovelifey: [Photography] Tips for Successful Star Trails Photography

Star trail photography – not so difficult with the correct planning and appropriate gear

In this short article I will show you, the night sky enthusiastic, that by using the right gear and proper planning, you too can make beautiful star trail photo.

Actually, shooting the stars is not that much different from any other kind of photography, and a decent composition is the key to an outstanding photo. Here are some star trail photography tips to help you.

Camera pointed to North/North-West with an artificially lit foreground.

Prepare your gear

A DSLR camera (or one that has Manual shooting mode) with fully charged battery.
Plenty of room on your memory card. I suggest shooting all in RAW as you’ll get better results later in post-processing.
A wide angle lens. Anything between 10-20mm will give you good results. You can shoot also with a longer focal length but the results will be less impressive. Using a wide aperture is also essential to allow lower ISO.
A strong, steady, tripod. When placing it, make sure nothing will cause it to shiver from a passing wind.
A remote control (preferably not wireless). If you have a way to program intervals in your camera, the remote is not necessary.
Stuff to help you pass the time – coffee set, snacks, a comfortable chair, etc.

Camera pointed to North with an artificially lit foreground .

Planning ahead

Before going out there, you must consider there is some planning needed to be done.

Choose your location carefully (there is no place for spontaneity). There are several things to consider, but most importantly you need a dark location, as far as possible from light polluted areas. Consider that city halos are visible at night for a very long distance, so get as far as possible from light sources. The darker the area you’re, the more stars you’ll see.
Consider an interesting foreground item to be used as your anchor in the photo. It is not enough to shoot the stars, you want to have a nice foreground to make your photo interesting and unique. Find yourself a big tree, an interesting rock formation, a pier on a lake, or any other item to be used as your anchor.
Learn about the weather and the moon phases – to get a good, clean shot you need a good, clear, dark sky. Choose that period of the month when the moon is not visible in the night sky (or is smaller like crescent moon), and make sure the forecast does not predict too many clouds. High humidity is also not good, as it may accumulate on your lens and result in blurry frames.
Consider the rotation of the stars and the Earth, as this will determine the appearance of the final result. The best results (in my opinion) will be achieved by shooting to the North (photo above) or to the South-East (photo below). Since Earth and the North Star are moving in the same direction, at the same pace, it appears as if all stars are rotating around the North Star, so having it in your frame will result in getting circles of stars. Shooting to the South-East will grant you with an almost horizontal line, that is concave in one corner and convex in the opposite corner. The stars rotation speed is 15 degrees per hour around the North Star. That means that stars closer to the North Star will make a shorter distance in comparison to those further away (also, the longer you’ll shoot, the longer the lines will be).

Camera pointed to South-East with foreground lit by surrounding light pollution.

Getting started

#1 Pick a foreground anchor

Although you may want to show as much of the night sky as possible, it cannot stand alone. Your photo must rely on a “strong” anchor / foreground if you want your viewers to be really impressed.

#2 Get there before dark

In most cases, it will be quite difficult, to the verge of impossible, to build your composition at night, in total darkness. It is better to arrive before night falls and it gets too dark to see. The last minutes of the day are your best time to plan and build your composition.

#3 Compose your shot

This is now the moment you place your camera and composing your frame. Remember to consider not only the appearance of your foreground in the frame, but also the direction that the camera is facing (as explained above).

Camera pointed to North/North-West lit by surrounding light pollution. Trails looks fragrant due to passing clouds.

Camera pointed to North/North-West lit by surrounding light pollution. Trails looks fragmented due to passing clouds.

#4 Shoot for the foreground

Take the first shot which will be used as the foreground of the frame. If you want your foreground to be a silhouette then all is good. But, if you want details to be shown, you will need to have at least one frame lit up. This can be achieved if few ways

Shooting one frame during twilight
Use a high ISO and longer exposure
Using an outside light source such as flash (it is good to use a CTO gel for the right color temperature). Your goal here is to get one frame that has good detail of your chosen foreground. It is better to take few options using different ISO level / exposure time / lightning options to be able to choose the best result afterward. When satisfied, you can move on to do a test frame of the sky.

#5 Setup and test camera settings for the night sky

Change the settings of the camera to get the best result for the night sky, without interference of light pollution. You need to see as many stars as possible, and to make sure they are in focus. The camera needs to be in Manual mode (or Bulb if using intervals). White Balance needs to be decided by you, and not on Auto mode (preferably in Tungsten mode, it will give you more blue in your image). Aperture set as wide as possible and an exposure time of around 30 seconds (with intervals you can set it to longer, but not more than a minute, for the sake of your sensor – it gets too hot).

You can change the ISO to get lighter or darker sky as needed, but not too high to keep a smooth, clean frame. Once satisfied with the result, keep the settings and erase these test frames (just make sure to keep the foreground frames you did in step #4 above).

#6 Take a couple dark frames

Camera pointed to South-East with foreground lit by surrounding light pollution coming from behind.

Take one or two dark frames. This is done by putting on the lens cap, and shooting with the settings you chose in step #5 above. These frames will be used later in post-processing. Make sure you remove the cap once you’re done this part!

#7 Take your interval shots

Lock the shutter release controller or press start if doing intervals. Wait to see that it works properly, and a new exposure starts immediately after one ends. Now it’s time to let the camera work for as long as you decided, while you rest or go do something else, but make sure you keep a distance and are not adding light into your camera or composition. For a good result, it is advised to shoot for at least two hours, especially when shooting to the North.

#8 Take two more dark frames

Once your intervals are finished, before moving the camera, repeat on step 6 and take a couple more dark frames.

This is it, YOU made it! All is finished and you can go back home for the post-processing part.

Post-processing star trails

First, from the foreground frames, choose the one that looks the best and process it to your liking. In this frame you can ignore the look of the sky, and if possible, it’s even better to darken it. When you’re happy with it, convert to JPEG or TIFF.

A frame taken during blue hour to be used as foreground.

Next, move on to the sky frames. Process the first one to improve the appearance and visibility of the stars. In this frame you can ignore the look of the foreground, and if possible, it’s better to darken it. Synchronize your settings to the rest of the sky frames. Export or convert the files to JPEG or TIFF.

One of the frames taken for the stars.

If you did any lens corrections, apply them also to the dark frames, then convert them to the same format as the sky frames.

Move on to the software you use for combining the frames – you can choose StarStax (Mac and Windows) or Startrails (Windows only) which are both free, very easy, and efficient. Upload the frames to their dedicated location (dark frames goes separately – the software is using them to subtract burned pixels from the final result).

The result of merging all the sky frames in Starstax.

The foreground frame can be handled in one of two ways – (a) placed together with all other sky frames or (b) left aside for merging it later to the final result, in Photoshop.

If you are working with StarStax, I recommend marking the Gap Filling option (in Startrails it is called: Lighten-screen-blend). It will make the processing time a bit longer, but the final result will be smoother.

If you chose to add the foreground image in when stacking the sky image, the result you’ll get is the final one and you may need only some fine-tuning to be done in Photoshop. Due to the time passed from the shooting of the foreground frame to the sky frames, you will notice a dot in front of every trail. These are the stars captured in the foreground frame. I see them as an interference in the overall look and erase them one by one.

If adding the foreground image in Photoshop later was your choice, then now is the time to put it all together. Load the foreground frame and the star trail frame as layers in Photoshop, and merge them into one using a layer mask. This option is better when the sky in the foreground frame is too bright.