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View Full Version here: : Collimation, caster and focus query


rathalian
25-06-2011, 05:04 PM
I had my first look through my new 10" Dob today while lining up the viewfinder with the scope.

Before I did I ran up the laser collimator, lined up the secondary and then went to line up the primary.

After loosening the primaries lock screws it aligned fairly easily however locking the mirror again was tricky i.e. took a number of micro adjustments of the lock screws to get to maintain the alignment. Any hints here to make this process easier or is it the nature of the beast?

Also, I assume that there is a limit to which an eyepiece is able to focus? i.e. when I was using my 25mm eyepiece (f5 / 1250mm tube) I noted I had to pull the eyepiece about 2/3 way out to focus on a light pole nearby while I was lining up the scope and viewer. Focusing on an object further away I could put the eye piece in all the way.

And finally, on the Dob base for the 10" scope would you recommend larger heavy caster wheels for portability (wheels with locks) ?

DavidU
25-06-2011, 06:24 PM
Yes it can be fiddley collimating but it gets easier the more you do it.
My Dob now has ball castors fitted as they are very low profile and nice and wide so the work on grass.
Newts are a bit sensitive to focusing on close objects.
http://www.taiwan-casters.com/files/furniture-ball-casters.jpg