2 replies to this topic

[tomhole]

Not sure if we have all migrated yet, so I put this in both forums.

Found a very nice fellow who took me up on my offer. I am
completing the transaction for a set of Denk standard binos and
1/14" OCS. This should be fun!

I could use a little help with the concept of the OCS. I have an
XT10 10" f/4.7 1200mm dob. My cycloptic observing goes from 38x/1.5
deg to 400x. I like very widefield for the spacewalk effect, and
like to see how far I can push the XT10 on planets and globulars.

The only pairs of ep's I have are the 25mm and 10mm Orion plossls
that came with my two XT scopes. The 25mm is ok, the 10 is not so
good. I also have a 25mm Orion Epic, 14 mm Meade UWA, 10.5 mm
Pentax and 9mm Orion Expanse (I have a 32mm UO but it is 2"). I
don't see me doubling up a 14mm Meade UWA in a bino, and can't
afford to double up the Pentax. I'll see how the Orion plossls do
and figure out what focal lengths I would like and go from there. I
know I want to have a range of 48x to 375x (that's what works so far
in the XT10). I use a televue 2x barlow, 2.5x powermate and 5x
powermate to get a good mix of powers. I usually end up at 48x,
100x and 200-250x. But there have been a couple nights that have
allowed 400x.

With the 1 1/4" OCS in 1.2x mode I can get the low power views, but
the ep focal lengths get really small for the high power stuff. If
I put it in 3x mode, I can't get the wide fields I would like. How
do you guys work through this? I cannot afford to build a premium
bino ep set right now, so I am looking at UO orthos and buying
duplicate Orion Epic and Expanse ep's.

Thanks and can't wait for first light with the new Denks.

Tom

[Tom T]

Tom,

FWIW - The shorter expanse eyepieces are supposed to be quite good, and the longer ones not so hot, but the shorter ones might be too much power when used in 3x mode.

I recently added a pair of 13mm t6 naglers to the line up, and I am pretty happy with them, but the 12.5 mm orthos really aren't *that* bad for fov. I had thought I was going to get rid of the 12.5 orthos, but now I'm not so sure. Yes, I think the orthos are that good.

The 25mm plossls would give you around 60x, and 150x, while
12.5 orthos would give you around 115x, and 300x. 18mm orthos would give you around 80x and 200x. I find 200x to be a very useable power from my site.

For higher power, I find wider fields aren't quite as critical - but then again I do much of my high power observing with tracking.

Have you ever considered a poncet platform for your scope?

Tom T.

[tomhole]

Tom,

I have an equatorial platform that I built for the XT10. It works great, tracking nicely as high as I can push the scope. I was viewing M13 at 429x Sat night with it. I got the 5x powermate so I could take advantage of those few nights of good seeing and not miss anything. The 14mm Meade UWA with the 5x powermate gives me the 429x, which was wonderful on M3 and M13.

I have the 9mm Expanse and it gives great views, but it has blacked out a lot for me. I still have it and may grab another one from Orion to see if they work better bino. If I could use my barlows/powermates with the bino, I could get a pair of 24 Pans and spend the whole night with just those.

Clear skies,

Tom