LSST camera lens

[SkyHiker]

Mounting the LSST camera lens of 5' diameter:

The SLAC lady presented some incredible numbers.

For instance the suggestion that you could see a golf ball on the moon with it. Really? If the golf ball is 4 cm in diameter at 400,000 km distance the angle is 1e-10 radians. For lambda/D to be that number with lambda, say 6000 Angstrom or 6000e-10, D would have to be 6000 m. The LSST is nowhere near that size.

Also, the LSST is a plain wide field telescope therefore no adaptive optics, so the resolution as limited by the atmosphere's turbulance is no better than that of my Z12. So what is the benefit of these incredible specifications that are also astronomically expensive? For sure you will capture a lot of light but of very limited resolution. Am I missing something here?

[yobbo89]

That's cool but i'm a mirror type of astronomer , the event horizon radio telescope can see a resolution of a bee on the moon, i wonder what the big mirrors can do . i would like to understand why they use a refractor lense over mirrors designs with adaptive optics, i guess they can still do adaptive optics towards the imaging end

[SkyHiker]

That's cool but i'm a mirror type of astronomer , the event horizon radio telescope can see a resolution of a bee on the moon, i wonder what the big mirrors can do . i would like to understand why they use a refractor lense over mirrors designs with adaptive optics, i guess they can still do adaptive optics towards the imaging end

Yea the event horizon telescope was basically the size of Earth, about 6000 km radius so D=12e6 but lambda is in the mm range let's say 1 mm so lambda/D is also about 1e-10 so a big 4 cm bee, that would work.

No adaptive optics possible because of the large angle. AO has to deal with a single narrow air column, so it's only good for exoplanets.