How to take photographs of the night sky
Did you ever wonder how to capture the splendor of the night sky? Look no more! This shot is not difficult, it’s really just a matter of setting the stage. While planning your nocturnal escape, let me take you in the following lines through it step by step.
First things first, we need to choose the location. Because of various factors of our modern life such as light pollution, stars are hard to spot in the city. The ideal location is one of total darkness. Such spot can easily be found using information provided by Darkskyfinder. Once you have the location, check the local weather. Ideally, a clear sky will make our stars shine. Take into account the moon phase, the best results in night photography are when there is no moon in the sky, what astronomers call new moon nights. Milky Way position on the sky during the night varies during the year and it is different based on geographical location. A good information source is Stellarium, a mobile sky app map that estimates the position of the stars and the moon phases in real time.
Finally, ready for a road trip? Let’s start preparing the photographic gear. Using a tripod is a must since night photography requires long time exposure. A well build tripod to withstand the environments, steady over long exposure, will do the job. Next on the list is a camera with manual exposure and RAW capability. I strongly recommend investing in a full frame camera. The 35mm sensor will improve low-light performance, and capture images with less amount of noise at high ISO.
Now, how about the lens? A fast-wide angel lens will make the cut for night photography. To capture the full extent of Milky Way, a lens with 14 - 24 focal length range is ideal, with a wide aperture (F/2.8) that will allow more light.
One important step is to set up the focus. This might be a difficult task considering that darkness of the night will not permit the lens to auto-focus. The best way around this issue is to focus the lens manually: adjust the lens in camera’s live view mode, focusing on a bright star. An alternative is to simply pre-focus the lens during the day.
Once the camera is set up to manual, three important parameters need to be adjusted: exposure time, ISO, and aperture. Because stars and Earth move continuously, we need the exposure time to freeze the movement; otherwise, the stars will appear as a trail. The best way to determine the maximum exposure time is to divide 500 by your focal length (for example for a 14mm focal length on a full frame body, the maximum exposure time is 500 divided by 14, which equals 35 seconds).
Now that we found out the maximum exposure time to get our sharp stars, let’s continue setting up the exposure. In order to capture light as much as possible, we will set up the camera at the fastest aperture available. The exposure time is also a factor. Start with an ISO of 3200 and 30 seconds exposure. This would require a series of trials until you find the best exposure. Depending on your camera, you can try varying the ISO from 1600 up to 6400. Just play around with ISO and exposure time until the correct exposure is obtained.
The last but not least important step in our night adventure is our shot composition. Although the Milky Way is the main subject in our frame, to create a strong image is important to use elements from the foreground: rock formation, man-made structures, mountains, trees, water surface or even a person. To spice the things up one can try some light painting using a LED, external flash or the most common light that we always have with us, the light from the cell phone. At this step, imagination has no limits.
Safety rules to keep in mind: be aware of your location, have a cell phone and a map with you, bring plenty of fluids, and always have extra clothing and batteries.
Good luck, wish you dark nights and bright stars, and Happy New Year!