Astronomy

[Yamaha2112]

Very cool! Haven't heard of the 500 rule - even in astronomy forums. Learn something new every day. Thank you!

In general, you can follow the "500 rule" to avoid celestial motion showing up on a picture: compute ((500 seconds) divided by (focal length in mm)).
Eg, if you're using a 24mm lens, 500/24 ~= 21 seconds maximum exposure (long enough for tons of stars to show up at reasonable ISO).
Eg2, if you're using a 200mm lens, 500/200 = 2.5 seconds maximum exposure (not very long unfortunately).
Some people use 600 instead; YMMV.

Adjust for equivalence (I believe your crop factor is about 1.5, so if you've got an actual 24mm lens, it will behave like a 36mm lens for the 500 rule computation).

 

[John Fitzgerald]

You could join the forums on "cloudynights.com". I have been on that forum for over 13 years and have over 50 years experience in amateur astronomy.
Any and all your questions could be answered on that forum.