[Tropo-Bob (Bob)]

Originally Posted by CAAD9

Hi everyone,

I've read this whole thread with quite a bit interest. I have a refractor question too. I don't know if I should start a new thread or if it's ok to ask in this one. Well anyway here it goes:

What solution for wide field observing?

I'm mainly into visual observing.

I use biggish fast dobs for going deep, but Open clusters and rich star fields lose their lustre in these.

I have a pair of 11 x70 binos but I find them too heavy for star viewing.

I have a cheap 80mm (400 fl) refractor, which I acquired as a sort of wide field proof of concept.

The results with the short 80 are mixed. The widest view is 3.9deg tfov through a 32mm plossl. That is wide enough but the viewing is poor. Very low magnification and with a washed out background sky. Colours are off at the edge.

I note that when I put the type6 Nagler 13mm in, the seeing through the scope improves immeasurably, to the point where I actually like it. However the 13mm cuts the tfov down to 2.5degrees, thereby mostly defeating the purpose.

So my wide field / refractor question is:

1) is it the OTA that needs upgrading? I get that for Photography you need the better OTA(ED, doublet, etc), but is that also as vital for visual?
2) do I move up the food chain in the eyepiece department, something like a 24 mm 68deg afov EP? That would maximise tfov through a 1.25" focuser but improve magnification and exit pupil.
3) try to do something about mounting the binos to make them more star viewing friendly?

Any and all views are most welcome.

Thanks in advance.

Adam

A better optical tube is the way to go. Having an ED or triplet lens really gives better visual images of the MilkyWay etc, as well as the bonus of providing good views of the planets.

Adam, I briefly had a 80mm F5 scope, and like U, I noticed that it only gave acceptable images with an EP that had an exit pupil of 2.something mms. An ED Scope costs a lot more, but it is worth it!