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Ep's for yard cannons.....

Started by Greg Shaffer, 02/05/2010 10:47AM
Posted 02/05/2010 10:47AM | Edited 02/05/2010 10:51AM Opening Post
Just getting started putting together an 8" f/15 build. This will be my 1st refractor over f/9 so I have no experience with choosing EP's for long focal length refractors.

Looking for advice/recommendations for quality EP's primarily for planetary use with an f/15....I currently have a set of Pentax XW's for my use and a set of Hyperions for everyone elses use smile Both of which work wonderfully in my shorter F/L stuff but I doubt they are ideal for f/15 based on what I have read. While I am sure the Zeis sets are wonderful I am not looking to spend THAT kind of money lol....Personally I prefer putting my funds in quality rather than a name AND quality.

From what I have gathered while both the XW's and the hyperions will work they may not be the best match for a f/15?

Any and all advice appreciated.....


20" MidnighTelescopes f/5
8" f/16 Muffoletto Achro
Meade 6" AR6 f/8.0 Achro
Celestron C11
Parallax PI250 10" F/5 Newt
Vixen FL102S,NA140SS,R200SS
80mm Stellarvue Nighthawk with WO APOupgrade lens, 90mm f/16.67 Parallax Achro
LXD75/LX200, Mini-tower, GP-DX, CG5 ASGT, LXD650, GM-8, G11, GM-100, GM-150EX, GM-200 and a Gemini G40
4" portable AP convertable 44" or 70" pier
Stellarvue M7 Alt-Az, TSL7 Pier/Tripod
12.5" f/5 MidnighTelescopes DOB Swayze optics
Monroe GA
Posted 02/05/2010 11:10AM #1
I had a set of Hyperions that I used in my 120mm/F12.5 refractor. I wanted something that would also work at F4.5 so I replaced them. If I had stuck with just the refractor, I would still have them.

The 24mm was not the greatest and was my least favorite of them all. (I had 24, 17, 13, 8) The others were just great but the 8mm was exceptional value for the money and the views through my refractor were very good and so very comfortable. I can't imagine the Pentaxs you have would be anything but better.

Why not keep what you have until you see how they perform? With eyepieces, they just keep getting better as the F ratio slows down. I bet they will be simply wonderful at F15!

Posted 02/05/2010 02:06PM #2
Hi Greg,

I owned a D&G 8" F/12 a few years back and had a set of Pentax XLs and Pentax SMC orthos. Both were superb as was a Meade 14mm UWA (series 4000, not the newer versions- which are probably fine too but I have never used one). The long focal length is very easy on eyepieces. You will find with something like a 3000mm focal length that simple eyepiece designs will give excellent performance.

Since selling the D&G, I replace the XLs with XWs and the SMC orthos with two sets of Zeiss 1.25" Abbes from 4mm to 34mm. Both are - in my experience -as good as eyepieces can get and your XWs will be fabulous in the big refractor. A friend who has a D&G 11" F/15 also owned Zeiss Abbes but sold them and bought two complete sets of UO orthos. He found the performance so close 90% of the time that he felt the substantial savings were better spent elsewhere. One place you might consider spending the extra cash is on a high quality binoviewer. The Moon and planets through good orthos and a binoviewer are stunning!

Baader orthos are a very good choice as well. I had sets of them for a while and liked them a great deal. But the UO volcano top orthos come up more often on AM and are really hard to beat!