3 ms·
Here's a comparison of bad and good seeing (captured with a D = 90 mm telescope with a solar Hα filter): https://app.astrobin.com/u/GreatAttractor?i=246828#gal
by gattr 1y ago
Here's a comparison of bad and good seeing (captured with a D = 90 mm telescope with a solar Hα filter):
https://app.astrobin.com/u/GreatAttractor?i=246828#gallery https://app.astrobin.com/u/GreatAttractor?i=246828#gallery
Technically speaking, in the first half of the vid the incoming wavefronts are distorted (the Fried parameter r₀ is smaller than the telescope's diameter D) and do not focus to a clean, tight Airy pattern ([1]). In the second half, r₀ is above D and we're left with just some rubber-membrane distortion (the wavefronts are tilted this way and that, but remain mostly planar), which can be corrected in software.
[1] https://en.wikipedia.org/wiki/Airy_disk https://en.wikipedia.org/wiki/Airy_disk
- barbazoo 1y ago> Excellent comparison! Thx for sharing :-) > No problem! For all those occasions when laypeople ask about your imaging and the importance of seeing comes up. > 26 Jul 2016 Love that this resource has been kept alive for almost 10 years now serving its very purpose.
- dylan604 1y agoI've been out in very poor seeing conditions, and it is just miserable. I was only doing wide angle and not using a scope, but the sky was so turbulent that I couldn't get proper focus. For those of us in the northern hemisphere, the best time for imaging the center of the milky way lines up with summer. Summer is just horrible seeing conditions in my area with >100° temps deep into the night with high humidity levels. Every now and then a new moon lines up with a nice thunderstorm which clears out the air and brings down the temps. Anyone want to take bets on the over/under of how often that happens?!