Trevor Jones' awesome website that covers almost any topic related to astrophotography you can think of.

AstroBin, a place where 50,000+ share images

Cloudy Nights forums, mecca for astrophotographers - a great source of info and help

THE home of plate solving. Upload any night sky image and it will tell you what you're looking at, where it is, and much more

Adam Block's astrophotography tutorials

Jerry Lodriguss's Astrophotography

Bill Snyder's Astrophotography

Russel Croman's Astrophotagrophy

David Collings's Blue Ridge Observatory

Steve Cannistra's Starry Wonders

Begining Post-processing (not Seestar, but…)

Cuiv the Lazy Geek (consistently good stuff)

Try a YouTube search for lazy geek S50 for more

noise: what it is, what to do about it

Deep Sky Imaging from A to Z