Image a fisheye Milky Way

Ultra-wide-angle lenses capture our Galaxy crossing the whole sky. Here's what to consider

- Pete Lawrence

The night sky can be breathtaking, especially when it contains bright views of the Milky Way from a darksky location. But what's the best way to capture the entire stretch of the night sky? There are several methods, but as ever compromises have to be made.

A camera with an interchangeable lens system such as a DSLR or mirrorless camera gives you the best of all worlds, allowing you to go wide-angle or mid-angle. A wide-angle lens has a focal length of 17mm or less, a mid-angle is 18-40mm. Anything over this is getting in too close to the subject to be considered all-encompassing.

If you choose a mid-angle focal length, you'll be able to cover a decent portion of the Milky Way, but you'll need to consider mosaicking shots together to cover all of it. However, seemingly perfect shots can then reveal issues such as lens distortion and edge vignetting, so be prepared to put significant time into a Milky Way mosaic in order to get something that looks natural.

An alternative is to use a wide-angle lens, essentially capturing most of the visible part of the Milky Way in one fell swoop. It seems an obvious choice to reduce workload, but wide-angle lenses have drawbacks of their own.

As with meteor photography, using a wide-angle lens may seem the ideal route - catching a trail is down to luck, but the narrower the field of view, the less chance of success. So it seems a no-brainer to choose a lens that covers the entire sky in one go.