totally OT: excellent astronomy program
 

Tipped off by https://www.makezine.com/blog/ , I downloaded a great program on the weekend.

If you've ever looked up at the night sky and wondered what the heck you were seeing, this is the program for you. Sort of like Google Earth for astronomy. Virtual sky.

- https://stellarium.org

You just enter your location in the settings (click a world map or enter lat/long), and you get a "live" view of the heavens above that point and you can zoom, pan & tilt 360 degrees around you. You can speed up time to watch the planets & stars rise & set or run time backwards. Or enter a date to see what was going on in the sky at any given time.

eg. When sailing in the Gulf of St. Lawrence in Sept, I watched a spectacularly brilliant planet rise just minutes ahead of the sunrise one morning, and figured it must have been Mercury. Wrong! I used this program to go back to that date & location and "re-run" that dawn's events to learn that it was actually Venus I had seen.

Put the program on a laptop and take it outside with you at night. I did this with my nephew on the weekend. We went out with a pair of binoculars with a mission: to find one of the few spiral galaxies (M31 near Andromeda) that you can locate without a telescope. We found it! I'd read about it in books, but never actually tracked it down before. With this program, it was simple. A VR teaching aid.

Lots more features that I won't describe here. Definitely worth checking out if you have the slightest interest in the night sky.

https://stellarium.org/img/rotation/rotate.php

Very cool, I used to use a similar web based program, but this is much nicer

Yup, tres cool.

Oh, and I forgot to mention above: it's free to use.