I know of them for making telescopes, astronomy gear and binoculars. Celestron been around for many decades, and their stuff is good. I have some of their telescopes and optical eyepieces myself. I looked at their website and they do indeed make LiION power banks (to power their telescope electronics) so it's probably the same company that sells your heater/power bank. I would trust them to make something much better than my cheap Chinese junk heater. A heater would be a good idea for astronomy - I remember freezing my butt off more than once back when I was actively in the hobby. Standing around at 3:00am in the dark, in the Colorado mountains, without moving much is cold - even in the summer!