3 ms·
I was wondering about that. I guess at the altitudes the SR71 operated at, at least the brighter stars would be visible.
by ams6110 8y ago
I was wondering about that. I guess at the altitudes the SR71 operated at, at least the brighter stars would be visible.
- the8472 8y agoThey don't have to be visible to the human eyes, just visible to instruments. With band filters and a narrow field of view you can get a stronger signal that sticks out from the the approximately uniform sky background. I mean the altitude helps, but it's not necessary.