Graptharshammer

Thank you Nigel, Chris Lock and Happy-Kat!  Light bulb started to go on after reading your explanations.  I'm fascinated by the idea of taking so many short exposures and coming up with something as awesome as the photos on this thread.  Really amazing stuff people are doing with stacked images.  I appreciate you taking a few minutes to educate the newbies like me on terms that might not be readily obvious in their meanings.  You guys are great!

New to astroimaging and have been following this post with much interest because of the Alt/Az component.  I have a question though, much talk has been made about L subs, subs...What is a sub if you can spare a second to educate a Noob on some of the slang?