Pentex E.P.s

I got to look through a 7mm & a 14mm XL this weekend at NiAG. I thought the 14mm showed a little color compared to my 13mm NAG type 1 with my 13mm being just a tad sharper. The 14mm showed a red fringe on jupiter and Saturn. The 7mm was awesome, Very sharp and crisp views with a lot of contrast. It darkened the sky down without dimming the object being viewed. I may be interested in the 7mm in the near future and was wondering if all the pentex XL were the same. It seems not because the 14mm gave a less sharp view than the higher power 7mm. I have heard about the XL's having better performing f.l. that others. Is this true. I am interested in some info on these E.P.s so would like to hear from people who use and have used these E.P.s with short f/ratio newtoians scopes to f/8 refractors to f/10 SCTs.

Thanks

Joe

I've owned all the Pentax XLs except for the 28mm, and I've used them in a 10" f/5 Newt and 6" f/12 MCT.

My first reaction to your report is surprise at seeing a RED fringe around Jupiter and Saturn in the 14mm. That is bizarre. I've never seen red fringing in any Pentax XL, or any other eyepiece that I can recall, for that matter, and the 14mm Pentax XL was as sharp as anything in the MCT. My problem with the 14mm Pentax XL in my 10" f/5 Newt was the field curvature--the edge was defocused when the center was focused and vice-versa.

Each Pentax XL shares the same comfort and feel, but there are performance differences. I personally think the 5.2mm, 7mm, and 10.5mm are head and shoulders above the 14mm and 21mm. The 40mm is, of course, an entirely different design. It isn't perfect, but it does represent a reasonable tradeoff between size, weight, cost, and edge correction for scopes down to f/5 or so.
--
Mike

I recently purchased a 7mm Pentax XL here on Astromart. I already had a Pentax SMC ortho 7mm and I wanted to see just how well the two compare. I've used both quite a bit in my 10" F6 Newtonian and 80mm F8 refractor. In the 10" on Jupiter the image in the ortho is almost imperceptibly brighter than the XL but the two are tied in terms of low contrast detail on Jupiter. I find myself using the XL much more because it's easier to view through and gives a much wider field which works great for globular clusters, small gallaxies, etc. It has also become my favorite eyepiece for solar observing since it yields a large image of the Sun that still fits well in the f.o.v. of the refractor.

Joplin

Joe,
I find the pentax models work quite well in my Discovery 12.5" F-5 and in my astrosystems 16" F4.5 dob. Excellent contrast and virtually no distortion with the 10.5 mm model in both scopes.I don't know why you experienced a problem with the 14mm unit;that is weird.
At any rate, it's good to see a post on eyepieces in the eyepiece forum, compared to what I've been reading recently...

Joe,

I have only the 10.5 for my C9.25 f/10 but it has become my favorite eyepiece when conditions are right (lots of light pollution here). I need a shorter focal length and am debating whether or not to get the Meade 8.8mm UWA or go all the way to the Pentax 7mm. The Pentax is a known entity for me and the most comfortable eyepiece I have ever used so it weighs heavily on my decision. Can't beat the 20mm eye relief, adjustable eyecup, and Hutech's price of $215.

Thanks for all the replys!

Joe