Which one, Orion Stratus or Pentax XF

[Spiney (Steve)]

Time to upgrade from the GSO plossls, eye relief is a concern to me.
Which 8-8.5mm eyepiece would you choose for a 12" Reflector. I've narrowed it down to either the Pentax XF 8.5mm or the Orion Stratus 8mm.
I like the eye relief of both, the size of the Pentax and the AFOV of the Orion?
Opinions and suggestion welcomed.

[mark3d]

just to add to your purchasing dilemma you might want to consider baader hyperions too

[mbaddah (Mo)]

Originally Posted by Spiney

Time to upgrade from the GSO plossls, eye relief is a concern to me.
Which 8-8.5mm eyepiece would you choose for a 12" Reflector. I've narrowed it down to either the Pentax XF 8.5mm or the Orion Stratus 8mm.
I like the eye relief of both, the size of the Pentax and the AFOV of the Orion?
Opinions and suggestion welcomed.

I recently purchased over the weekend both Baadar and Hyperion eyepieces and think they're great. I don't know what the Pentax is like though...

Whilst the coating on the Hyperion look alot better, i found (from brief testing last night) in practise make very little difference. I may be wrong. Be warned though these eyepieces are big, and you will need counterweights ( It tilts my 10" truss).

[citivolus (Ric)]

All things being equal between the Baader and Orion offerings, I find that the Baader has a nicer fit when used in 2" focusers. The two Stratus's I have don't go in far enough to be retrained if my scope flips, so I have to set the retaining screw very tight. With the Hyperion, though, there is a recessed section on the nosepiece for retention. I have the Stratus 8 and 21mm, and the Hyperion 17mm, so I'm assuming (perhaps incorrectly) that the rest of both series share similar designs with these.

Edit: if you are using these in a 1.25" focuser, you won't see this issue. Some people may also prefer the Stratus design, as it doesn't have a lip to get hung up on the ring when removing the eyepiece. I guess it is personal preference. I'll probably sell my Stratus eyepieces and switch to the Hyperions, though, as I prefer to use a 2" diagonal and with my new mount the scope spends a bit more of its time rotating through strange geometries. PM me if you want a deal on an 8mm

[janoskiss (Steve H)]

Take the XF, no question about it. I had both. I still have the 8.5mm XF (and since bought the 12mm also). There is no contest. It is one of the best EPs out there near that focal length. The XF is superior wrt every aspect of optical performance: contrast, transmission, off-axis correction for astigmatism and false colour. Not a marginal difference either. It's also a lot lighter and smaller. Works extremely well even at f/4 (Stratus is of little use at f/4).

[erick (Eric)]

I borrowed janokiss' eyepieces for a couple of nights last year. After the first night, the Stratus stayed in its box. Too big and too heavy, compared with the Pentax.

[Spiney (Steve)]

Hey why aren't you guys at work. I wasn't expecting this many replies so soon.
I've been leaning more towards the Pentax XF 8.5mm because of its smaller size and also from what Janoskiss has posted previously. If these are that good I may have to consider buying the 12mm as well!! Only hope the better half doesn't find out.

[erick (Eric)]

Originally Posted by Spiney

Hey why aren't you guys at work....

Shuuuuussh! Not so loud!

[ausastronomer (John Bambury)]

Add me to the list of 8.5mm Pentax XF proponents. It gives up marginally to the 8mm Stratus/Hyperion in terms of AFOV and that loss is minimal, but it smacks it in every other respect.

The Stratus/Hyperions are exceptional value for money eyepieces and see widespread use because of their wide range of focal length availabilities. Unfortunately the Pentax XF's only come in 8.5mm and 12mm as they are designed for use in Pentax Spotting scopes. Consequently you can't make up a set of them. In a one out shootout at the 8mm/8.5mm focal length the 8.5mm Pentax XF is an easy winner.

Cheers,
John B

[Kokatha man]

Hi Steve - I work for myself The best thing anyone can say to you is to check out different eps if you can at all possibly do so!

There's no doubt that the comments people make about Pentax eps is valid: you can't argue with the stats - but there is an analogy with audiophiles here: the stats on frequency responses et al are amazing with some of the gear around, but the question allways has to be asked; does the individual have the capacity to pick up on some of the finer nuances delivered, and is there setting up to scratch to accomadate aforesaid?

With eps this involves not only the scope, but, as someone said in this forum, the limiting optics of your own two eyeballs (not to even begin to talk about average seeing conditions!).

Having said that I've only recently purchased 2 new eps: an 11mm T6 Nagler and a Vixen LVW 17mm - mighty fine eps and I do appreciate them, moving (like you) from mainly GSO's. But those 2 set me back $700+ and someone might argue that I could've gotten close for much less than half - price.

This is not to disagree with anything anyone's said on this thread, but it is alllways horses for courses and I think the golden rule is try first if at all possible - just thought a cautionary "devil's advocate's" comment was worthwhile, regards, Darryl.

[janoskiss (Steve H)]

Originally Posted by Spiney

I've been leaning more towards the Pentax XF 8.5mm because of its smaller size and also from what Janoskiss has posted previously. If these are that good I may have to consider buying the 12mm as well!!

Unlike the 8.5mm XF, the 12mm has significant field curvature which you may find bothersome. So try before you buy. The 8.5mm however I can recommend without reservation. It has virtually no FC to my eyes in any scope I tried it with.

[DJDD]

Originally Posted by Spiney

Hey why aren't you guys at work. I wasn't expecting this many replies so soon.

everyone is at work- which is just to support their habit- er, hobby.

and there is one post every three minutes on the list so...


thanks for the thread. I was looking at the stratus for the soon-to-be-purchased telescope but may investigate other options.

[wavelandscott (Scott)]

Also in the mix I would offer as a good "value" competitor the TMB Planetary eyepiece line...

I have not compared them to the Pentax XF so I can not comment there...
I have compared them to the Pentax XW...the XW is better but, at a much higher price. Better how you might ask...to my eye it was a bit better in all categories (build quality, eye relief, FOV etc.). That is not to say the TMB is bad at all...it is just not a "high end" piece of gear.

The TMB Planetary eyepieces are available here in Australia from Frontier Optics at AUD$139 (from memory).

I find the eye relief to be good and much superior to plossls of similar focal length...but will add that I do not wear glasses.

I would echo the advice shared by someone else earlier in the thread...if you can, try before you buy...

[Spiney (Steve)]

Many thanks for your opinions guys, I will be ordering the Pentax XF 8.5mm today and I'll hold off on the 12mm until I get the chance to look through one.
I'm self employed as well but the rain has put a spanner in the works, so I thought I'd do some retail therapy instead.

[programmer]

So how is it?

[Hagar (Doug)]

Having both Baader and Orion Stratus I can recomend both equally for their visual performance but on fit and fittings the Baader is an outright winner. I recently had a chance to visually compare the Baaders with equal sized Naglers in a TakFS102 with JohnG and we were both of the opinion that for the price the Baader were a great EP. The Baader fell away on overall field width and was a little low on star colour but otherwise not a lot in it.
EP's are really a personal choise. Some people never really look at edge of field so a little comma or curvature is not important to them and some people like me don't use an EP very much at all. I spend most of my time looking at a computer screen.
It is nice to look through a good EP that is clear and free of deformities.
I have not used a Pentax but they seem to rate very well. Dont discount some of the middle of the road priced EP such as Vixen, Baader, Orion and Williams Optics. They are all pretty good.

[westsiderailway]

Originally Posted by citivolus

Edit: if you are using these in a 1.25" focuser, you won't see this issue. Some people may also prefer the Stratus design, as it doesn't have a lip to get hung up on the ring when removing the eyepiece. I guess it is personal preference. I'll probably sell my Stratus eyepieces and switch to the Hyperions, though, as I prefer to use a 2" diagonal and with my new mount the scope spends a bit more of its time rotating through strange geometries. PM me if you want a deal on an 8mm

Not sure how to "pm" someone from the threads, am interested.

Don't worry, just figured out how to do it.