Chris Kelly said:
Its a 6" Newtonian : 100 cm from primary to secondary and 152 cm from secondary to eyepiece... I have a good 25 mm eyepiece and an OK 23 mm that I use primarily. I also have a 4 mm & 10 mm that aren't very functional in my area ( 1 hour west of Philly).
I foresee a trip into lesser radiant areas for better viewing. .............. Thanks for the input. I think it is f5.
Additionally, the observation you make about your 10mm and 4mm "... aren't very functional ..." is a very good one. They would be even less functional with a barlow. The reality is that they give "too much power" for your seeing conditions and scope.
As far as barlows go, getting a Celestron branded Barlow increases the chances that you might not have to change the focus much between using the Barlow and not using it (what is called parfocal). I have had good success with the Older Celestron Ultima 2x Barlow in this regard. If you can locate one used, give it a try.
This post was modified on 11/5/2017 4:33 PM