2 suggestions, if you're retracting the legs, and your main goal is astrophotography, leave the legs up all the way, this will increase how steady the telescope is. Also, although I HAVE NOT personally gotten one yet, they sell motorized focus devices that allow you to electronically adjust the telescope focus, for example: http://www.amazon.com/Orion-7395-AccuFocus-Electronic-Telescope/dp/B00077261C/ref=sr_1_3?ie=UTF8&qid=1390096908&sr=8-3&keywords=Motorized+Telescope+Focus

Just my 2 cents, defer to the pros here. Also, this doesn't answer all your questions you had, but hopefully will help!