Astronomical twilight

[AllanJ]

Pottering about on the computer this afternoon after setting the scope up outside under clear sky (it probably won't last), I wondered exactly what time astronomical twilight would occur. Short of using Stellarium to find out what time the Sun drops below 18 degrees, I could'nt see an obvious source.

There was a post by pete_l a few days ago giving sky darkness calendars as images for selected cities ([thread=123573]This post[/thread]).

I looked on the Royal Observatory website, and that gave a link to the US Naval Oceanography Portal Sun/Moon tables; that is useful, but you have to enter lat-long unless you are in the USA.

That is Here

Then I found the easy-to-use Skylink weather site that simply asks for country and station (city or airport), and it gives the times for astronomical twilight. That site is

Here

If you have a better or more obvious source, please correct / augment my post.

I've got time for a G&T and a bite to eat before it gets dark.

Allan