teft@startrek.website 11 months ago
Hubble is essentially a Keyhole satellite so I assume if they flipped it around we’d have really clear photos of earth similar to the one trump got in trouble for showing on live tv.
Not really. Hubble is set up to image objects light years away and moving relatively slowly.
Keyhole stats as set up to image the earth's surface that is only hundreds/thousands km away and moving quite fast.
Two different missions would lead to two different designs.
That would lead to different focal lengths not different designs completely. Both optical systems for HST and KH were designed by Perkin Elmer so I’ll stick with my first thought that they would be very similar in capabilities.
Did you watch the video?
The tracking problems Hubble would have imaging the earth surface are a direct guide to what differences the design would be.
Wouldn’t tracking be software and not hardware?
Did you finish the video where they essentially say what I said in my first comment? Hubble and spy satellites share a lot of the same technologies. I wasn’t aware of the speed issue but other than that they are similar like I said.
QuinceDaPence@kbin.social 11 months ago
Those spy satellites are focused at the distance of earth. Hubble is focused at infinity or near-infinity
them@lemmy.world 11 months ago
Is focus to infinity that different for these types of scopes compared to a conventional camera which focuses to infinity after a couple hundred metres? I would have thought the draw back would be the focal lengths giving you a very small area in frame.
QuinceDaPence@kbin.social 11 months ago
Focal length and aperture both affect how much focus matters.
Also with most regular cameras, from what I've heard they actually have their max focus slightly past infinity to accound for thermal issues so the general advice for doing astrophotography is to focus on the subject, not just whacking it to infinity.