telescope - How do I find the RA of sunset and sunrise in a specific location?

There is a very nice web-based utility called Staralt that I frequently use before observing runs.

This has lots of observatories pre-programmed or you can put in your own latitude and longitude AND altitude (can you do that in Stellarium?).

To quote the website - "you can plot altitude against time for a particular night (Staralt), or plot the path of your objects across the sky for a particular night (Startrack), or plot how altitude changes over a year (Starobs), or get a table with the best observing date for each object (Starmult).".

You can also do handy thing like produce plots, charts and tables or show where the moon is with respect to your targets.