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pentax 5mm xo ep..worth it???

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#1 whirlpoolm51

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Posted 28 March 2012 - 03:25 PM

i was in the market for a really nice quality narrow field planetary ep to use with my es ar102 refractor or on that i could also use with my f4.5 dob

i have been to caught up in all the wide field ep hubbub that i forgot how good plossls and other narrow field eps could be

after alot of thought and research i have came to the conclusion that i want to try out the pentaz xo series

i was goignn to try out some baader orthos or myabe even some siebert monocentrics but i have had good experiences with pentax and want to keep the family tree of my pentax collection going... what do you guys think!!???

pentax 2.58 and 5mm xo
siebert 6,4,3mm monocentric id's
baader orthos

and can anyone please tell me whatever happened to tmb's supermonos???? why are they no longer made??

#2 HfxObserver

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Posted 28 March 2012 - 03:46 PM

The 5mm XO is worth it, simply the best performing eyepiece without regard for TFOV.

Images are colour free and crisp directly to the edge.

-Chris

#3 Roy McCoy

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Posted 28 March 2012 - 04:03 PM

The XO's are on sale at Adorama for $279.95 (Special Price in shopping cart)

If you call our sponsor they will usually match.

#4 BillP

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Posted 28 March 2012 - 04:04 PM

IMO the XO is "The" standard for a planetary eyepiece. I've found no other 5mm that beats it, not even monocentrics. Review.

Price point was too high for such an esoteric eyepiece like the Supermono for it to continue. With most folks using fast scopes, only 1/2 of the FOV is without field curvature in the Supermono. Still though, its on-axis is about as good as it can get.

Like with any classical planetary, the advantages of less glass and optimized build only come to the eye when the seeing and transparency of the atmosphere is at its best. That said, on "average" days you may not see anythign more. But if you are a purinst for planetary observing then you look forward to those best evenings to see the extra these extreme eyepieces can provide.

No one knows anything about the new Baaders...however their price point is low enough that IMO definitely worth a try. I look forward to testing some once they come out. If they are as good as the UO HDs or BGOs then will be a wirthwhile investment.

#5 AZStarGuy

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Posted 28 March 2012 - 04:16 PM

Buy the XO. Everything Bill said is spot on. The only downside is the eye relief. It is the tightest I have ever experienced, but the views are second to none.

#6 saemark30

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Posted 28 March 2012 - 04:26 PM

The XO's looks like a plossl with a barlow built into it.
I think they are discontinued.
You can achieve the same thing with your favorite 15mm or 16mm OR, PL, RKE eyepiece and 3x barlow with no eye relief problems.

#7 whirlpoolm51

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Posted 28 March 2012 - 04:46 PM

thanks guys noy my decision is made i am going with the xo's

the narrow field of view should not be a problem with tracking and in my opinion the contrast with the backround sky in narrow field eps should be astounding

i will also give them a try on some of the more compact galaxies too!!!!

alvin huey, the author of some great pobserving guides for the arps and hicksons says that his narrow field eps are key in detecting faint detail in most of the arps!!!

i had no idea they were on sale either!!!!

i just hear they are heard to find now but i have seen a coupe of places that still have them in stock!!!

#8 Sean Cunneen

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Posted 28 March 2012 - 06:28 PM

I bought one a few years ago and sold it about a year later. I regretted it so much I bought one again over Christmas and it resides permanently in my "do not sell!" box.

Sean

#9 Jim Romanski

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Posted 29 March 2012 - 10:41 AM

The XO in my best performing planetary eyepiece. I don't know if it has anything to do with the number of lenses since that would be speculation on my part and it has 5. But the views are very clean and the background sky black. It appears to have a very good light baffling system.

I'm someone that usaully want more eyereief but for some reason the XO doesnt' bother me. I can use my glasses but then the field is quite limited. But since the exit pupil is pretty small with a 5.1mm eyepiece I don't see any benefit with my glasses on. The XO has the flatest field of any eyepiece I've seen even in a very fast scope.

The only thing you might not like about it is that it seems to use an actual rubber eyeguard and smells like an automobile tire. I kind of like my stinky little XO.

#10 gnowellsct

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Posted 29 March 2012 - 10:44 AM

I bought the XO 2.5 "with extreme scepticism" because of the too-short fl and was astounded at how well it performed. "Don't let your apo leave home without it." I bought the XO on a lark, putting in a very low bid on an astromart auction, and ended up winning when the actual winner got cold feet and backed out.

So it became apparent to me that here as elsewhere the Pentax engineers had "nailed it" in terms of how I react to an eyepiece. I had never viewed through tiny glass and enjoyed it so much. Not UO orthos, not my ZAO IIs.

So....I went ahead and bought the 5 XO because I was worried about Pentax leaving the field. I haven't used it yet, but given how excellent the 2.5 is I find it inconceivable that the 5.0 will be bad.

Greg N

#11 whirlpoolm51

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Posted 29 March 2012 - 03:00 PM

ahhh i just looked to go buy it and i found them on telescopes.com on discount for 300 but they only have the 2.5

so then i looked at optcorp and they have the 5mm for 360!!! what to do what to do

#12 AZStarGuy

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Posted 29 March 2012 - 03:46 PM

The 5 is every bit as good as the 2.5 Greg. You will like it. I wish Pentax would have built out the line a bit more. 2.58 & 5.1 is hardly a line. I wonder what the thought process was at the time? The 2.5 let me push 306x in a 4" Lomo APO last year with no image breakdown here in AZ. Glorious night indeed!

#13 dscarpa

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Posted 29 March 2012 - 03:50 PM

Adorama doesn't have them in stock but you can order the 5 XO for $280 or the 2.5 XO for $260 which includes shipping. David

#14 Mike Hosea

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Posted 29 March 2012 - 04:50 PM

The 5 is every bit as good as the 2.5 Greg. You will like it. I wish Pentax would have built out the line a bit more. 2.58 & 5.1 is hardly a line. I wonder what the thought process was at the time?


Dunno, but at the time I thought it was just a tentative move which could have led to more focal lengths if the reception had been good enough. However, their introduction roughly coincided with the hoopla over the TMB Supermonos and AP SPLs, and then ZAO-II not long after. I think with just a couple of focal lengths (one of which was too short for larger scopes) and the timing, the XOs were largely overlooked. Over time, the cream has risen to the top, and if anything maybe the ZAO-II's helped matters by skipping from 6mm to 4mm (lots of planetary eyepiece aficionados don't want to use a Barlow). However, in a business sense the damage may already have been done, and by then the TMB Supermonos and APL SPLs could have discouraged Pentax from expanding the line for a completely different reason.

#15 Kutno

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Posted 13 April 2012 - 05:09 AM

ahhh i just looked to go buy it and i found them on telescopes.com on discount for 300 but they only have the 2.5

so then i looked at optcorp and they have the 5mm for 360!!! what to do what to do


Anthony,

All the best with the path you chose to follow; but you cannot go wrong with the 5.1mm Pentax XO. In head-to-heads with a very fine 5mm UO Ortho, one notes how sharp the Ortho is, and that it provides very good dark backgrounds; but the Pentax performs better than that, and even more: If you look long enough through each ocular during a session, there is a "smoothness" in the images provided by the Pentax that is not equaled by the Ortho.

#16 Sarkikos

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Posted 13 April 2012 - 07:32 AM

Bill,

The Pentax XO 5mm is definitely on my wish list of planetary eyepieces.

But I'm curious about the design. The XO has 5 elements in 3 groups. Erfles have 5 elements in 3 groups. The XO has 44deg AFOV. Erfles have about 60deg AFOV. Is the XO a stopped-down, optimised Erfle? :thinking:

:grin:
Mike

#17 george tatsis

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Posted 13 April 2012 - 08:02 AM

The 5 is every bit as good as the 2.5 Greg. You will like it. I wish Pentax would have built out the line a bit more. 2.58 & 5.1 is hardly a line. I wonder what the thought process was at the time?


Dunno, but at the time I thought it was just a tentative move which could have led to more focal lengths if the reception had been good enough. However, their introduction roughly coincided with the hoopla over the TMB Supermonos and AP SPLs, and then ZAO-II not long after. I think with just a couple of focal lengths (one of which was too short for larger scopes) and the timing, the XOs were largely overlooked. Over time, the cream has risen to the top, and if anything maybe the ZAO-II's helped matters by skipping from 6mm to 4mm (lots of planetary eyepiece aficionados don't want to use a Barlow). However, in a business sense the damage may already have been done, and by then the TMB Supermonos and APL SPLs could have discouraged Pentax from expanding the line for a completely different reason.


Most logical explanation I have heard so far! It does make sense after all.

George

#18 Richard Low

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Posted 13 April 2012 - 10:43 AM

I have both XOs 2.5mm and 5mm. For those who appreciate the best planetary eyepices, you wont regret getting either of these two.

#19 johnnyha

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Posted 13 April 2012 - 12:17 PM

Has anyone compared the 5XO to a 10mm ZAO-II with the Zeiss barlow? I realize the Zeiss setup costs 4X more so the Pentax wins that round. :grin:

#20 Mike Hosea

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Posted 13 April 2012 - 12:55 PM

Has anyone compared the 5XO to a 10mm ZAO-II with the Zeiss barlow? I realize the Zeiss setup costs 4X more so the Pentax wins that round. :grin:


Tammy has! Do a search. IIRC, he found the 5XO slightly better in some sense, but only just slightly.

#21 Sarkikos

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Posted 22 April 2012 - 09:46 PM

Well, after reading the information about the Pentax XO 5mm here on CN and elsewhere, I finally succumbed and ordered one - actually backordered one - from Adorama at their special price. I hope the rumors of its demise have been greatly exaggerated, and I'll be receiving one in a matter of weeks, rather than months or not at all.

I went back and forth about whether to order the 2.5mm or 5mm. I decided on the 5mm because it has such good reviews, and 2.5mm would be a bit much for my prime planet scopes on most nights. I don't see paying that much for an eyepiece whose focal length would be best for my small fast rich-field telescopes.

So far, IME, the most contrasty and most detailed views of planets have been with pairs of eyepieces in my binoviewer. I'll make an exception for the Pentax XO 5, however. It will have to remain single.

I think of the Pentax as an early birthday present to myself.

Mike

#22 Stellarfire

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Posted 07 May 2012 - 04:06 PM

Did anyone try a pair of Pentax 5mm XO in a high-quality binoviewer like the Baader Mk V?
Generally, eyepieces with focal lengths not under 10mm are recommended for binoviewers. Nevertheless, I tried a pair of Delos 6mm in the Baader Mk V, to my surprise I did not encounter any merging problems. So the Pentax 5mm XO perhaps might work nice as well in a binoviewer. Any binoviewed lunar/planetary experiences so far?

Stephan

#23 Sarkikos

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Posted 07 May 2012 - 06:36 PM

A pair of Pentax 5mm XO might work in my binoviewer, but it's not going to work in my budget. Time for a little austerity! :poke:

I do have several bino pairs under 10mm, including BGO 9mm and LER 6mm. I had no problem merging these in my Burgess Binoviewer. Though since I need at least a 1.9x OCA for my 8" and 10" Newts to come to focus, the magnification was 253x and 380x respectively for the 9mm and 6mm eyepieces. This was a bit high for Jupiter, but I've gotten good views of Mars at these and higher powers.

:grin:
Mike

#24 helpwanted

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Posted 07 May 2012 - 07:35 PM

Well happy early birthday Mike! Let us know your thoughts on your first light!

#25 Sarkikos

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Posted 08 May 2012 - 06:39 AM

Thanks! I don't know when - or even if? - Adorama will replenish their stock of XO 5, but I think I'll keep my backorder open. It was a good deal. There's no way I would have bought one at the full price.

So far, my experience has been that a decent pair of eyepieces binoviewed for planets will trump a single eyepiece, even if that eyepiece is reported to be better. But we shall see.

Mike






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