Image source: Wikimedia Commons
How to Get Started in Astrophotography
After you’ve spent some time enjoying the view of the stars and familiarizing yourself with some of the sights, a lot of amateur astronomers begin to look for another challenge.
Beyond merely peering into the wonder of the cosmos, many new stargazers want to have a lasting image that they can see beyond the moment. In search of this lasting image, many amateur astronomers turn to to astrophotography.
We recently came across this fantastic video from At-Bristol Science Center with huge amounts of useful information for people looking to get into astrophotography.
If you’ve never heard of At-Bristol and the At-Bristol Science Center, it’s a non-profit organization in Bristol, England that seeks to disseminate scientific information and make it accessible to everyone. The At-Bristol Science Center YouTube channel is a treasure trove of tips for amateur astronomers.
In the video, Ross Exton and Lee Pullen from the At-Bristol Science Center’s Live Science Team give us a series of indispensable astrophotography tips for when you’re ready to dip your toe into astrophotography.
Before they begin talking about how to photograph the night sky, Ross and Lee talk about the sort of equipment you need. While certain cameras would, no doubt be better than others, they make a point of noting that you don’t need anything exotic. All you need to have is a camera with fully manual settings. Most DSLR cameras will have this capacity.
For the long-exposure shots involved in astrophotography, it will also be necessary to have a shutter release.
2. Go Outside to a Dark Location
This one seems obvious, but it’s an absolutely essential element of astrophotography. Sure, a lot of people like to stargaze from a window, but if you really want to get to see some of the best that the night sky has to offer, it will be necessary to go outside.
To be clear, not just any backyard will do if you want to get to see some of the deep sky objects that look great on film. In many cases, if you live in a city, you’ll have to go somewhere where you can escape the blight of light pollution.
Image source: Wikimedia Commons
Light pollution is the net effect of all of the lights in an urban area. Every street light, headlight, porch light, and lamp, however small, all add up to a halo of light that surrounds our cities and population centers. Because the images that we receive of celestial objects are light, this halo interferes with our ability to see them.
If all you can do is to get outside the city limits to a less well-populated area, then you definitely should do that. The ideal would be to go to a place far from the population centers.
On the bright side (ha!), that halo of light can actually add contrast to your photos, contributing an aesthetic element that can actually make them better and more interesting.
3. Set the Lens to Manually Focus On Infinity
In order to focus on objects light years away, the first thing you have to do is set the lens to manually focus on infinity. Move the setting to “M” for manual. Then, twist the barrel to the infinity symbol.
Setting the focus to infinity makes the stars and objects tighter and more in focus, whereas if you don’t take this step, they’ll just show up as glowing, blurry globules.
4. Set the Aperture
After you’ve set the lens to manually focus on infinity, you have to set the aperture to its widest possible setting. This is done by finding the lowest possible f-number on your camera.
The f-number is the focal ratio or relative aperture, and represents a ratio of the lens focal length to the diameter of the entrance pupil.
In essence, the aperture is the hole in the lens that lets light in. Because you want to let in as much of that celestial light as possible, it’s necessary to open the aperture as wide as possible.
5. Change the ISO
ISO is the camera’s sensitivity to light. The higher the ISO number, the greater the sensitivity to light.
The difficulty in this step is that over-increasing the ISO can lead to a significant amount of light “noise” in your photos. However, if you don’t set the ISO high enough, the camera won’t have sufficient sensitivity to the small amounts of light you’ll be trying to capture from the night sky.
The reality is that this is a balance you’ll have to strike between oversensitivity and lack of sensitivity. The noise shows up as speckled grains in the photos, so if you’re seeing that, you need to move change the ISO to a lower number.
6. Change the Shutter Speed
In order to let in the most light possible to achieve the necessary exposure, you’ll need to change the shutter speed to let in as much light as possible. This involves setting the camera to “bulb mode” which allows for any shutter length desired.
If you have one available, it’s advisable to sue a remote release. This keeps the camera from shaking.
7. Change the Focal Length
You’re looking for a low number here. In the video they use 24mm or 18mm, but in truth the number you use will differ depending on what sort of camera you have.
Note also that in the video they talk about telephoto lenses. This is not a must, but of course if you have a powerful telephoto lens, your results will, all things being equal, probably be better.
And that’s it. With the right equipment and these useful tips, soon you’ll be taking amazing pictures of fascinating phenomena from the night sky.