Posts Made By: Ralph Junius

Floyd Blue's excellent eyepiece review has prompted me to make a few general comments on Pentax XL eyepieces.

Most of my viewing over the last 5+ years has been with a C14 and a 6" f/8 Celestron achromat. I have purchased and used a lot of eyepieces over the last 25 years including a complete set of Pentax XL's, which as a whole are still my favorite set of eyepieces.

I have found the 7mm Pentax XL to be an outstanding eyepiece. Unfortunately, viewing recently primarily with f/11 and f/8 telescopes it has not really been possible to carefully evaluate the 5.2mm Pentax XL, but I have done some viewing with a 4"f/5 TV Genesis and several 80mm refractors to the extent that it is obvious that the 5.2mm is at least very good. Floyd's report confirms this and further that it is better than very good, which does not surprise me.

The outrageous part of Pentax XL eyepieces to me has always been that the 5.2, 7 and 10.5 are almost the size and weight of small hand grenades, yet they still pass more light and than most simple plossls and orthos. When I pull out a tiny, almost weightless ortho or plossl and put in a huge XL of the same focal length, it just amazes me that typically the Pentax's pull in fainter diamond dust in a star cluster, more clouds in a nebula, and more detail in a planet in spite of all the extra glass.

In general I subjectively find the 7 is slightly better than the 10.5, the 10.5 better than the 14, etc. down to the much maligned 28 which is at the bottom, not that the 28 is not a very good eyepiece, easily besting IMO a very good 32mm TV Plossl for instance.

The 20mm eye relief, adjustable eyecups, the fact that they are parfocal, the large field of view, the very high overall optical quality of the set, and the unequaled ease and comfort viewing keep the whole set of Pentax XL's in my number one eyepiece case. BTW I have come to believe ease and comfort is a lot more important than I earlier had thought, because I generally always see more the longer I look thru an eyepiece.

Without going further on and on I'll say that the XL's survived an assault by the Radians. The 13mm T6 Nagler appears to easily best the very good 14mm XL, and of course the 28mm XL is not even in the same league with the 24mm Panoptic, but so far Al Nagler has not figured out how to put together a complete set of matched eyepieces that match the XL's.

My C14 was destroyed in Katrina and in its place I recently acquired a new 20" NightSky dob. Now I get to re-test all 150 or so eyepieces with a John Hall f/4.5 Pegasus mirror. I'm looking forward to it.

In closing on this post I'd like to say I'm real happy Floyd didn't "moderate" me in the previous thread and further that Mike Hosea and others handled it a lot better than me!

Clear Skies!

Ralph Junius

I want to get the regular "Pro" version but wouldn't mind getting the "Plus" version if it has the full Pro version in it. Does it?

Can I disable or not install the CCD Mosaic so that I can use it just like the regular pro version?

At that point will it not bog my computer down any more than the regular Pro version?

Help!

Has anybody compared the Delos line to the XL or XW Pentax's?? My full set of
Pentax XL's were recently stolen returning from a star party at a motel. It
looks like TeleVue is finally taking direct am at the XL/XW Pentax lines. I
really liked my XL's and I assume the XW's are about the same.

Any opinions on whether I should come back with a set of Delos' or go with the
XW's???

Bob, I started similarly with the Pentax XL's except I didn't have anybody like High Point to get demos from. Bought the 14mm first; it blew me away, then I gradually bought the whole set. Expensive, but worth it. Besides the great optics, they are the most comfortable eyepieces I have ever used. I've got some Naglers now which I also like a lot, but I have to say I don't notice the difference between the 65 degree and 82 degree field most of the time.

The Pentax's are parfocal all the way from 28mm to 5.2mm and offer great eye relief. The eyecups are extremely user friendly, no kidney beaning, extreme comfort and didn't I say the optics are great?

Clear skies!

Ralph Junius

If Al updated the optics I'd go for another set if they are smooth. The "safety" indents drive me crazy on all of today's eyepieces.

A goto dob is no different.

Ralph Junius

I would strongly suggest you at least try the Brandons particularly if you have a long focus telescope. Even if you don't, if you couple them with the Brandon 2.4x Dakin barlow you will still probably find them to be outstanding. You'd have to check, but I'd presume they are still priced at about $200 each. They have a somewhat narrow field of view and are poor off axis, but are extremely sharp on axis with absolutely outstanding contrast. Vernonscope claims single layer coatings provide more contrast than multicoatings, and comparing the Brandons to many other multicoated eyepieces, something is responsible for the added contrast that I see. Note that the 8mm has no eye relief.

Despite their wide field design with a lot of glass, IME the Pentax XL's are also outstanding planetary eyepieces, particularly the 5.25 and the 7, but out of your current price range.

The TV plossls are as good as most people think they are and are relatively inexpensive. The TV barlow and the powermates mate with these eyepieces exceptionally well IME.

The UO orthos are also as good as people rave about, but come in two different flavors and visually are radically different. To my eyes the volcano tops are the better planetary eyepiece (more contrast) and the HD's are clearly better in deep sky (more light transmission). Both are outright inexpensive and probably the best bang for the buck out there.

I find the Type 4 Naglers to be very good planetary eyepieces, better than the other Nagler types by a wide margin for lunar/planetary.

Ralph Junius

Scott, I'm with Ed on this one. Theoretically, you are absolutely correct, but when I check with my eyes at the eyepieces, my Pentax XL's and Nagler Type 6's stand up well to everything I've looked thru from monocentrics all the way thru the 4 element jobs. I hate to admit it, but, to my eyes and to my astonishment, the T6 Naglers and Pentax XL's are much better on axis eyepieces than I thought possible considering the number of elements and the field of view. Of course, another way of looking at this is that there is still substantial room for improvement in the simpler designs.

Thanks for the response guys. I purchased a 12mm Delos and have done some casual testing against the 10mm Ethos, 12.5mm UO Volcano Top (VT), and 12mm UO HD all from my light polluted observatory(The WHO)which houses a C14 Edge.
The following is my "observing for the pure pleasure of it", qualitative, non-sientific comparisons. Targets included M15, M42, M31, Jupiter, Saturn and Sun thru Thousand Oaks filter.

Even though the focal lengths are different, my gut from my eyeball is that on axis the Delos and Ethos are similar optically. The UO VT is superior in every way optically except field of view, ie, more stars and greater contrast and resolution on planets. The UO HD is has even slightly more light thruput but lacks the contrast (shades of color) of the UO VT. Both UO's have zero blackout issues. In previous rather extensive testing, my recollection is that the XL's on axis were closer to the UO's.


Initially, I was going to just replace the XL's with a set of XW's. However, I noticed using a friends XW's at the DSRSG thru my TEC 140 recently that they seemed to be ok but not as luxuriously comfortable as the XL's. Specifically, they seem to be somewhat prone to blackout and for at least some of them the cups don't screw out far enough to get your face hard enough on the cup to steady your eye to eliminate. The 12mm Delos has similar issues, but the eyecup extends far enough to minimize the problem. I don't recall nearly as much of an issue with the XL's but maybe I'm just romanticizing them.

Please note that the blackout is still minor in all these eyepieces compared to some of the old TeleVue Naglers but here I'm talking of ultimate comfort where you may comfortably keep your eye in an eyepiece for a half an hour or more.

I actually compared another dozen or so eyepieces from my remaining (after theft) 75 or so collection, but it gets too complicated and long discussing all these eyepieces.

I'm half tempted to buy one of each type in 10mm and go at it, but so far have not been able to bring myself to part with that much bread.

Any thoughts, comments, different experiences, etc?

Ralph