Quote:
Originally Posted by wavelandscott
scopes will you use? Can you throw a high quality refractor into the mix?
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Hi Scott,
The 2 main scopes I will be using are my 10"/F5.3 newtonian with Suchting mirror and my 14"/F4.5 newtonian, with Zambuto mirror.
Both of those scopes are excellent optically. I will also use the 18"/F4.5 Obsession when seeing conditions permit. The 6mm Delos will give 350X in that scope, so it won't be useable all the time. I will do the evaluation with and without a paracorr in all the scopes. The 14" and 18" scopes have servocat tracking so they do give you the opportunity for critical high power evaluation.
I don't usually use refractors, except as finderscopes, as I am not an imager. However, I am hoping to gain acccess to an ED80, which is owned by a friend, for a night or two.
Quote:
Originally Posted by PlanetMan
For my own two cents worth (and assuming this isn't already on the cards) is there any chance of putting in a Pentax XW 5 or Pentax XW 7 into the mix - or is this likely to cause too many problems.
I personally think this is the clincher a lot of people would like to know about in terms of the Delos and how it compares with the venerable Pentax XW's.  |
Unfortunately at these short focal lengths a 1mm difference in eyepiece focal length makes a fairly big difference in magnification and it is impossible to directly compare and critically evaluate a 6mm eyepiece with a 5mm or 7mm eyepiece. For instance in my 10" scope those 3 eyepieces give 185X, 217X and 260X which is just too big a gap IMO. In the larger scopes the gap is even wider. In the 18" scope those 3 eyepieces give 300X, 350X and 420X respectively.
I do have a 1.8X TV barlow, a 2.5X TV powermate and a 2" 1.6X Antares barlow. I can put the 14mm Pentax XW into the 2.5X powermate for 5.6mm. The 10mm Pentax XW into the 1.8X TV barlow for 5.6mm and the 10mm Pentax XW into the 1.6X Anatares for 6.25mm, which is as close as I can get. I will certainly do that evaluation but it will be ever so slightly inherently slanted due to the fact that whichever barlow I use, it introduces additional glass into the light path.
Cheers,
John B