Quote:
Originally Posted by RobF
Even though guiding will be a bit easier at 800mm, an F4 scope is a bit trickier to collimate than F5, and the critical focus zone smaller. F4 is likely to magnify any issues with scope stability/construction versus F5.
My Newt is F5 and holds collimation very well. I don't have direct experience with F4 - again, probably worth reading around a bit here and elsewhere on the net. Remember you'll need a coma corrector (e.g. MPCC) to get a flat field in a Newt.
This thread talks about newts. More pros and cons to consider 
http://www.iceinspace.com.au/forum/s...ad.php?t=96521 |
Thanks Rob. After reading the thread you linked I am now pretty certain I'll got the 8" F5 route, as it seems to good compromise for what I want.
With Coma issues, is it 100% necessary to get this sorted straight away or will I be able to have lots of viewing/learning/beginner photography before I need to worry about that?
Cheers
Mick