Canon U.S.A. Inc., to Provide 120 EF 400mm f/2.8L IS II USM Lenses for Expansion of the Dragonfly Telephoto Array Project

ColorBlindBat

EOS 90D
CR Pro
Aug 30, 2018
100
41
If my brain is working today, they should end up with an effective aperture of ~0.22.
 
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Kit.

EOS 5D Mark IV
Apr 25, 2011
2,236
1,542
I wonder what the advantage of using camera lenses over telescopes is for astronomy. 6" aperture telescopes can be had pretty inexpensively.
The formal rationale is very low lens flare of these particular lenses. Dragonfly studies galactic halos, they need optics with very low scatter.