If you are more into doing this locally than using a Webservice, have a look at astroplan based on astropy.
https://astroplan.readthedocs.io/en/stable/
This reminds me of this submission to Hacker News recently:
https://news.ycombinator.com/item?id=46330012
Very nice tool. If you don't mind, I've linked to it from our observatory:
https://www.alnitakobs.com/telescope/A widget version would be nice!
Interesting tool, would probably be super useful if I had more knowledge of the things floating around out there. I'm usually just concerned with photographing the galactic core on dark nights. I didn't have enough domain knowledge to figure that out with this tool though. I use PhotoPils on my iOS devices for astrophotography planning and that works great for my limited level of knowledge.