Posts Made By: Ralph Junius

Lyn, I'd suggest something that would give you about a 1mm exit pupil. At f/10 this would be a 10mm eyepiece. I'd suggest an 11mm TV plossl or a 10.5mm Pentax XL (which is more versatile). Anything from 9mm to 11mm will be useable many nights. The 9mm Nagler T6 would be very tempting but is expensive. The 10mm Orion ultrascopic is a very comfortable eyepiece. Below 9mm seeing is going to be a problem on a lot of nites. Clear skies!

Dave, I'm curious what you have your Genesis mounted on and whether you are satisfied with the mount. I have a Genesis non-sdf that I am considering taking off of my C14 and using it as a stand alone grab and go scope.

I am also interested in what the Cygnus Loop and the North American nebulas(e drop s) looked like thru the Genesis on what was apparently a very transparent nite. Clear skies!

Jerry,

I have 2 sets. They are as perfectly parfocal as any set I've seen. I use them in sets and I use them for binoviewing. I have a 28.7mm and a 15mm that date to the early '80; they are exactly parfocal with my newer ones; I have a similar situation with Televue plossls of different generations that don't fair nearly as well as far as parfocalization. As a point of reference, they are as parfocal as my Brandon set and my TeleVue plossl same generation sets. Clear skies!

Schuyler,

No eyepiece-telescope combo will make the sky look truly jet black, just darker and darker shades of grey with increasing quality. Of course this is just my experience.

BTW, I agree with everything Kalyan says except I generally prefer Pentax XL's at all focal lengths! Besides the Pentax's, for comparison I have about 75 other eyepieces of various name brand manufacturers. Clear skies and good luck with your next set.....eyepieces are a lot of fun and come in a full range of advantages and disadvantages.

Ralph Junius

Mike,

Thanks for the info. I do not have the 18mm. Purely on a visual basis the 12.5mm UO appears to be orthoscopic but who knows. The Televue plossls are way underrated IMO and this is not surprising to me. The TV's have a huge field of view compared to the UO's and appear to be well corrected. It may be that looking thru a straw like you do when looking thru a UO gives an orthoscopic illusion. Having as much angular distortion as you've measured does it fishbowl from pincushion distortion (which I presume it is) when panning like my 19mm Panoptic?

BTW, I have tried your AFOV method of measuring and am getting inconsistent results depending upon the position of my eye relative to the eye lense; larger AFOV the closer I am to the eye lense. Is there a trick or methodology that I am missing? I look thru the eye lense at a 24" ruler (just fit it in the view) and measure how far the field stop is from the ruler and then do the trig. Clear skies!

Ron,

I have a few SCT's. Here are my comments:

N5: Neat little scope but images are not up to my 4" TV Genesis in any department.

C9.25: Great scope but a good C11 will easily outperform it. My Genesis cannot keep up with this scope at all. Neither can my 4" f/15 Jaegars. Under certain conditions my excellent 6" Chineese refractor can equal it on the moon.

C11: Great scope; images can be as sharp as a C9.25 but as an added feature it gathers significantly more light. I find the ota easily transportable, virtually no different from the C9.25 in that catagory. The C9.25 is about the same length, by the way. As a matter of complete disclosure, I bought a C11 ota used on Astromart that will not hold collimation. It is now a problem that I will deal with myself or send the scope to Celestron for repair. BTW, collimated the images are excellent IMO. A friend of mine, Ron "Dewbuster" Keating, bought a C11 new from Company 7; it is an outstanding scope that at times practically keeps up with my excellent C14. The larger field of view of the C11 as compared with the C14 gives the C11 a significant advantage when viewing a lot of popular objects.

C14: Great scope but the ota is not as managable as the C11 or C9.25. I can and do handle this scope completely by myself but its not a piece of cake like a C11 ota.

All of these scopes need a G11 or equal. The new Celestron equatorial mounts look interesting. My G11 handles all of these scopes very well.

I would not consider a C8 because the C9.25 and C11 are substantially better IMO, don't cost much more (for a serious observer) and are just as easy to carry around IMO.

Bottom line, I consider the C11 on a G11 the ultimate easy to transport scope.

Ralph

Jim, I think your thinking is right on target but I have never viewed thru a UO Super Erfle. I have an old Celestron 20mm erfle eyepiece, and I'd say it does everything 20mm and 26mm plossls do. At 20mm its not going to be a planetary eyepiece anyway in your 6" f/8 where the plossls excel and if the coatings are good on the erfle you should give up very little in light gathering.

To tell you the truth I've been eyeing the 16mm UO erfle for quite a while to use in a finder scope. I have an old 16mm flat top UO Koenig but the Koeing has zero eye relief, though it does offer sharp, wide views. The erfle design generally has more eye relief than the Koenigs so I've been considering taking a chance. Can anybody tell us first hand about the UO erfles?

Nobody has mentioned the 7mm and 5.2mm Pentax XL's so I guess I may as well. I like Radians also but IMO the Pentax XL's are significantly more comfortable and deliver about the same image quality (of course we can argue forever about this over a lot of eyepieces) except less lateral color, with a somewhat larger FOV for about the same price.

One time I counted 13 craterlets in Plato with a 7mm Pentax XL. I had a lot of other eyepieces on hand that nite but none could match the 7mm Pentax XL. I have a full set of Pentax XL's and I like every one of them including the much maligned 28mm; the 7mm is the best of the set optically IMO. How Pentax does it with all those lenses I will never know. I also have about 75 other eyepieces but I am almost growing weary of testing them and the image quality is so good and consistent (and parfocal) thru the Pentax's that these days I frequently just bring out the Pentax's.

I am not saying that the Radians are not reasonably comfortable, but the Pentax XL's are the ultimate in comfort....loads of eye relief, great eyecup design, no blackout, easy for anybody including first time users to look thru. Twenty-five years ago I was not that interested in eyepiece comfort. The Pentax XL's have taught me that the longer you can actually look at an object the more you are going to see. The Pentax XL's are unequaled in that respect IMO. I don't think you can count 13 craterlets looking thru a scope for 5 or 10 minutes.

I may as well mentioned that I have taken a few peeks thru a 13mm Nagler Type 6. It appears to be an outstanding eyepiece. The whole line of Type 6's may also prove to be excellent planetary eyepieces despite their wide field design. They are comfortable too, but not like the XL's. Clear skies!

Ralph

I have a 12mm RKE and a 12.5mm UO Ortho. I have tested them rather extensively visually (along with a number of other 12mm eyepieces). IMO the UO is significantly sharper on axis and transmits more light than the RKE.

Further, the UO images are relatively blue, the RKE images are relatively red, which to my eyes makes the moon, planets and red stars in the RKE's all more colorful, which I like. The RKE's have a slightly larger field of view and are more comfortable than the UO's, which are also reasonably comfortable.

On the basis of sharpness and light transmission, I like the UO orthos better than the RKE's. When the RKE's were $40 it was a closer contest, but to me no contest at the same price. Edmund is completely out of touch with the amateur community these days; if they weren't they'd at least multicoat the RKE's.

The new UO HD orthos for about $80 from Helix are also interesting. I bought several, including a 12mm but have not tested them enough to make a definitive statement. They are all parfocal like the RKE's and unlike the older UO's. Being parfocal is worth $$$$ to me even if the eyepieces are no better than the older excellent UO orthos. Clear skies!