90
you are viewing a single comment's thread
view the rest of the comments
view the rest of the comments
this post was submitted on 06 Dec 2023
90 points (97.9% liked)
Videos
14311 readers
286 users here now
For sharing interesting videos from around the Web!
Rules
- Videos only
- Follow the global Mastodon.World rules and the Lemmy.World TOS while posting and commenting.
- Don't be a jerk
- No advertising
- No political videos, post those to !politicalvideos@lemmy.world instead.
- Avoid clickbait titles. (Tip: Use dearrow)
- Link directly to the video source and not for example an embedded video in an article or tracked sharing link.
- Duplicate posts may be removed
Note: bans may apply to both !videos@lemmy.world and !politicalvideos@lemmy.world
founded 1 year ago
MODERATORS
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.
Those spy satellites are focused at the distance of earth. Hubble is focused at infinity or near-infinity.
You'd just get some really blurry images.
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.
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 account for thermal expansion so the general advice for doing astrophotography is to focus on the subject, not just whacking it to infinity.