Creating a nighttime time lapse video may sound intimidating. Actually, though, it's almost as easy as taking a star trail shot and the results can be jaw-dropping. Though the magic of time lapse videography, we can make the celestial display overhead complete its trek across the sky in a matter of a few seconds. Best of all, you don't need much more than a DSLR, a wide angle lens, an intervalometer, a tripod, a high-capacity memory card (16GB minimum – 32GB preferred) and some time to sit with your equipment. As with other subjects, you can add camera motion with a slider or dolly to create dynamic, even dizzying effects for captivating presentations.
Most of the work in creating a time lapse of the night sky is done before the shoot, at least if you want to capture something really amazing. This first segment of the article will deal with that part of the process.
Preparation and Planning
You're going to want to know how to do a few things before you head out to your shooting location. Spend some time in your back yard or another convenient nighttime location learning these steps:
Exposure: Set your exposure mode to Manual and open the lens aperture to its widest setting. Set your shutter speed to 25 – 30 seconds. Using Live View and Exposure Simulation, find the ISO setting that gives you the best results. Remember that noise will increase as your ISO setting increases. Experience is the best teacher here, so practice.
Focusing: If your lens has an infinity mark on the focus ring, set it there and check it with Live View and magnification on a star. If there's no infinity mark, start by running your focus ring all the way to the stop on the distant end. Locate a star in Live View, magnify it and carefully move the focus ring away from the stop until the star is as sharp as possible. You may want to mark this position as infinity on your lens. You can also use a different, very distant object during the daylight hours to find the approximate spot.
File Settings: Setting your camera to save your exposures as RAW files will ensure that you have the most flexibility in editing your stills. It also avoids some of the potential problems with JPEG files in low light. You should also learn to disable high-ISO noise reduction if your camera has it. This will greatly increase the speed at which your camera saves files, and avoid problems with timing.
Other Equipment: Get to know your intervalometer and how to program it. If you're using motorized camera motion equipment, learn how to set it up and use it. If you don't have motion gear, but would like to, I recommend taking a look at the equipment at Revolve Camera. You'll appreciate the simplicity, quality and reasonable prices of their sliders and dollies.
Timing is important, for a couple of reasons. First, every constellation, as well as the visible segment of the Milky Way, “rises” and “sets” at different times each night, just like the moon. There are also times of the year when the features you want to include in your video won't be visible at all during the night. Second, if the moon is in the shot, you'll have a difficult time balancing your exposure. The best times for star videos is during the days before, after and during the New Moon.
To determine the best times to capture what you want in the night sky, you can consult one of many free resources, such as apps like Star Tracker or Photopills for your mobile device, or Stellarium for your computer. Take some time to see what's going to be visible and when, and try to keep the moon out of your window.
Location: Preparation also involves choosing a location with little to no light pollution, making sure you have everything ready to do the shoot and everything you're going to need to keep yourself comfortable and occupied while the sequence is being shot. You're going to be out there for a while. Check weather forecasts and be prepared for changes. Pick up a headlamp and a good book.
Rinse and Repeat
As annoying as I know this will be to many readers, I'm going to end Part 1 of this article here. That's partly because it's already long enough and mostly because you're going to want to be sure you've covered everything in this part before moving on to the actual night shoot.
Get your gear out and practice some daylight sequences. Last minute adjustments in the dark aren't going to be easy. Know how everything works. Make sure you've got focusing and exposure down for night skies. Get your gear list for the shooting excursion together. Then you'llbe ready to move on to Part 2. Meanwhile, here's a short time lapse video of the night sky to whet your appetite: