Re:Vera Rubin's primary mirror gets its first reflective coa...
by JumpCrisscross on Sunday May 05, 2024 @04:20PM
(#40267904)
> how the heck does a 3 mirror setup make sense? Can't a single mirror always accomplish the same goal?
Easier to make three smaller mirrors than one big one.
> why mirrors, with their blind spot where the sensor is, instead of lenses?
"Mirrors don't cause chromatic aberration and they are easier and cheaper to build large. They are also easier to mount because the back of the mirror can be used to attach to the mount" [1]. (And there are off-axis designs that avoid obstructing the incoming light.)
Easier to make three smaller mirrors than one big one.
> why mirrors, with their blind spot where the sensor is, instead of lenses?
"Mirrors don't cause chromatic aberration and they are easier and cheaper to build large. They are also easier to mount because the back of the mirror can be used to attach to the mount" [1]. (And there are off-axis designs that avoid obstructing the incoming light.)
[1] https://lco.global/spacebook/telescopes/reflecting-telescope...