Following on from Mike's article on Astrophotography with a Dob. I have a couple a questions which may not have been asked. I am wondering down to what F ratio would it be possible to run a vidoe cam similiar to Johnaton's SDM "Blackie" given the reduced "sweet spot " of the primary ??? I love the idea of not having to climb Jacobs Ladder to the eye piece but would like the option of doing some science with the "investment". Steve Kennedy is releasing an F3 mirror next year and Al Nagler will soon be bringing out a new "super Parracor" to suit very fast Dob's. Also could a field de rotator /focuser coupled with a stella cat be a better option for imaging????

Love to here back from the learned
Cheers Zubenel