Re: Orion Starblast 4.5 - replacement focuser?

Ed: There is always the JMI RCF, it used to be cheaper. I don't know the height... The kit is about $80.

http://www.jimsmobile.com/buy_rcf.htm

The is also the Kineoptics Helical crayford:

http://www.kineoptics.com/HC-1.html

Jon