Here’s a quick overview of the best lenses tested by Lenstip, suitable for Nightscapes and Astrophotography.

This is very much a work in progress. I will share access to my spreadsheet when I feel it’s done. Here are the scores:

Higher = better. Teal means tested myself.

The Best Lenses

This gets updated as we uncover more data.

How to interpret these numbers

I’ve factored in:

Clear Aperture Diameter (mm)
Suggested Untracked Exposure Time of the Galactic Core (seconds) = NPF rule, factor 1.5
Focal Length (mm)
Relative Aperture
Resolution MTF50 APS-C Edge 1 stop down
Chromatic aberration % FF Edge 1 stop down
Subjective Coma score FF Corner Wide open
1 stop down coma rating
2 stop down coma rating
Astigmatism %
Vignetting 2.8 FF
and lastly, if the lens has autofocus or not.

Laanscapes Astrophotography Lens Score: Longer lenses score better, especially if they're optically flawless.
Be aware that, the longer the lens is, the more affected by wind and tracking errors due to increased weight and surface area.
Laanscapes Nightscape Lens Score: Wider lenses with autofocus score better, compared to its astrophoto score.
Zooms score better than primes due to their flexibility.
Sharp, fast and optically flawless lenses score best overall, heavily impacting the score.
Laanscapes Night Lens Score: Combined astro + nightscape score, where nightscape capabilities weigh twice as much.

Added normal and telephoto prime lenses from Sigma and Samyang.
Added 3 wide-angle zooms by Sigma.
Reworked the scoring system so coma performance is paramount.
For nightscapes, wider lenses are better. For astro, longer lenses are better. Keep in mind that long lenses are pretty much worthless for nightscapes. Realistically, a 50mm can be used to frame a lone tree or other single feature against the Milky Way center, but it’s already useless for northern lights and limited in its flexibility.
With this new scoring system in mind, the Sigma 500mm scores 4 times as good as the next best lens. However, while optically flawless, you probably need an equatorial mount to handle this weight (3310 grams). And if you're entering that game, investing in a telescope is about a third of the price at that focal length. Telescopes are much easier to focus, are typically lighter and much better suited to capture the night sky. I’ve manually adjusted the global factor for just this lens, so it better fits the competition in this area. The Apertura 90 mm Triplet Refractor comes with a Field Flattener and a hard case. You can get this scope, a cooled color astrophotography camera and an equatorial mount and get professional results for less than the price of just the Sigma 500mm.