Tue Aug 29, 2017 12:45 pm
Tue Aug 29, 2017 12:59 pm
ed_b wrote:Hi all,
I'm new here and new to astronomy, and have a basic question - so this looks like a good forum!
I'm using the outputs from HMNAO Websurf for sunrise and sunset, and wondered if anyone can tell me how accurate these are?
In particular for sunrise/set, do they account for refraction of the earth's atmosphere, which makes the sun appear to be above the horizon even when it is geometrically below it?
And generally how accurate are these times? There's what seems to be a US Gov site, which suggests that even when multiple variables are entered, the output can only be within ±30s.
Any ideas? If this is one for HMNAO I can ask them, but wondered if there's a sort of industry standard that means it's too obvious a question.