Astronomy

Best app for looking at the night sky:

https://www.celestron.com/pages/skyportal-mobile-app

Free interactive star map and planetarium:

https://stellarium-web.org/

A great website for learning advanced astronomy subjects:

https://astronomyonline.org/

A website designed by NASA to teach children:

https://spaceplace.nasa.gov/

More resources and activities for children: 

https://astrosociety.org/education-outreach/education-resources.html

Articles and facts about celestial objects:

https://nineplanets.org/

Great for learning about current sky events and observing tips:

https://astronomy.com/

Same as above. Includes an interactive star chart:

https://skyandtelescope.org/

Astronomy magazine for the United Kingdom:

https://astronomynow.com/