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A Pentax ortho record?

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#26 RodgerHouTex

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Posted 08 May 2013 - 08:05 PM

Interesting. I never knew what SMC stood for.

#27 Jim Curry

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Posted 08 May 2013 - 10:41 PM

Roger:

Yeah, we bad.

Jim

#28 Sarkikos

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Posted 09 May 2013 - 07:08 AM

Interesting. I never knew what SMC stood for.


Super Multi Coatings.

Mike

#29 Sarkikos

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Posted 09 May 2013 - 07:17 AM

PJ Anway,

I've owned a set of ZAO's, several Pentax SMC's and the 5mm XO. I still have the XO. Personally, I feel it's the best 5mm of those I've used.


Sounds good to me! I've never owned a ZAO or Pentax SMC Ortho, but I do have the entire line of XO's ... both the 5.1 and the 2.5. :grin: I wish Pentax had produced XO's in a 10mm. They would have been great for binoviewing.

As a further note: the 5mm XO was advertised to have "smc full-surface multi-layer lens coating". So I guess it's a Pentax SMC too. :grin:


Yes, says so right on the barrel. :)

XO Eyepieces

Mike

#30 RodgerHouTex

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Posted 09 May 2013 - 06:40 PM

Ah who reads their eyepieces? :shrug:

#31 johnnyha

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Posted 09 May 2013 - 06:46 PM

Yep, premium glass prices have been on a crazy tear in the past 5 years. Other than the Nagler zoom, everything here seems to have appreciated 50% in the 3 years since I started my long-term planetary optics comparo (making it bloody expensive to complete some of the sets!).


At this rate, this little set will be worth $1.2 million when I retire in 30 years. Sweet (insanity).


What no bino sets? :roflmao: Oh wait, I DO see a few! :tonofbricks:

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#32 gnowellsct

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Posted 16 May 2013 - 06:23 PM

Some observers prefer the XO to the Pentax Ortho. Some prefer the Pentax Ortho to the XO. Some say the XO is at the level of the ZAO. Some even prefer the XO to the ZAO!

Mike


I prefer the XOs to the ZAO IIs in the 4 and 6mm range. The ZAO II 10 and 16 are wonderful though. I have yet to figure out why one needs any of this stuff with the XWs sitting there in the same box. The recreational value consists mostly, methinks, in being able to enter a discussion such as this. GN

#33 Jim Curry

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Posted 17 May 2013 - 03:40 AM

Shhh.

#34 Sarkikos

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Posted 17 May 2013 - 07:23 AM

Greg,

I prefer the XOs to the ZAO IIs in the 4 and 6mm range. The ZAO II 10 and 16 are wonderful though. I have yet to figure out why one needs any of this stuff with the XWs sitting there in the same box. The recreational value consists mostly, methinks, in being able to enter a discussion such as this. GN


Good to hear that you prefer the XO's to the ZAO-II 4 and 6. I had read that the ZAO-II 4 was the weakest of the series. I think I'll pass on the 10 and 16, also. Too long a focal length in my primary scopes for planet/lunar unless I Barlow, and then what's the point of simple glass?

So far I prefer the XO's to comparable XW's and Radians for planet/lunar and doubles. To my eye, the XO's have less scatter and an overall sharper image when the seeing allows. That's why I hang on to the XO's. But that doesn't mean I'm going to sell the XW's tomorrow.

Do you have an opinion on the Leica ASPH Zoom? IMO, if the Leica is as good as some observers say, it may replace my XW's. But I don't see it replacing my XO's or even my planet/lunar bino pairs. I can't help but think that the Leica enthusiasts have missed the mark when they consider it a top-tier planet eyepiece - unless perhaps the observer can afford a pair for binoviewing and has a wide enough IPD to accommodate them. I think the Leica's forte probably lies in deep sky.

Mike

#35 Paul G

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Posted 17 May 2013 - 08:11 AM

I had read that the ZAO-II 4 was the weakest of the series.


Optically the 4 is just as good as any others in the series. However, the 4 has extremely short eye relief, seemed to be the least popular of the series here in the US. I trimmed my eyelashes to observe with it. In Europe the 4mm ZAO I was the most prized of the series, garnering better resale prices than even the 34. Different strokes.

I think I'll pass on the 10 and 16, also. Too long a focal length in my primary scopes for planet/lunar unless I Barlow, and then what's the point of simple glass?


True, but a barlowed ZAO has 6 elements in 3 groups, six air-glass surfaces. The XO's unbarlowed have 5 or 6 elements depending on fl, 3 groups, and six air-glass surfaces as well.

#36 Sarkikos

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Posted 17 May 2013 - 08:26 AM

I believe it was BillP who said that he was not so impressed by the ZAO 4mm. From what I've heard, 4mm is a difficult focal length to do right, particularly for small simple glass. Witness the disappointment for the Brandon 4mm as compared to others in that line.

I think there is more to it than just the short eye relief. Personally, I don't let short eye relief deter me when there is a better image to be had. I really like the XO 5.1 at 3.6mm eye relief. The Brandon 6 at 3.6mm eye relief is very comfortable to me. I don't get the big deal about short eye relief unless it is ridiculously short to the point of being nonexistant, such as for the sphere eyepieces.

Mike

#37 Sarkikos

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Posted 17 May 2013 - 08:32 AM

Gus,

I think I'll pass on the 10 and 16, also. Too long a focal length in my primary scopes for planet/lunar unless I Barlow, and then what's the point of simple glass?


True, but a barlowed ZAO has 6 elements in 3 groups, six air-glass surfaces. The XO's unbarlowed have 5 or 6 elements depending on fl, 3 groups, and six air-glass surfaces as well.


Yes, true. But so far I prefer a well-designed eyepiece with built-in Barlowing to something added after the fact. Besides, I'm fishing for any excuse not to even think about buying the hyper-expensive ZAO's!

:grin:
Mike

#38 Sarkikos

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Posted 17 May 2013 - 08:49 AM

Greg,

I prefer the XOs to the ZAO IIs in the 4 and 6mm range.


Too bad the XO's only came in 2.58 and 5.1 flavors. A 4mm would have been nice, and I could have gone for a pair of XO 10mm's for binoviewing.

Mike

#39 dscarpa

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Posted 17 May 2013 - 09:59 AM

Even when barlowed my 24 Brandon when it comes to scatter bests my Delos, XWs, and such native. The darker background and special quality of the image is still there as well. Having all of the 1.25" TV barlows and Powemates I could get enough mileage of a 18 SMC to make it well worth $300 provided it doesn't have icky stuff between the elements. What's their FOV? A 18 SMC would also slot in nicely with the unused 16 Brandon 50th I picked up on Amart for $150. Should be here today! My plan to get a 16 ZOA has been shelved, just too much money. David

#40 jrbarnett

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Posted 17 May 2013 - 10:08 AM

That, or the fact that the XWs are pretty lousy large aperture DSO eyepieces compared to premium simple, low-element designs in some situations. :thinking:

When I swap TMB Supermonos in for the XWs in the 16" f/5.1, for example, I gain about 5-10% (SOTP) more resolved stars on most globulars. The XWs are lovely eyepieces for casual, general purpose observing, but they don't go very deep compared even to the Ethoses or even the new Deloses, much less any premium simple eyepiece.

But for looky-loos, and fueling goofy Siddarthic posts, XWs are splendid. But for me, the LVWs are much better than the XWs for such purposes. So even in that use case, the XWs are somewhat lacking. :winky:

Regards,

Jim

#41 dscarpa

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Posted 17 May 2013 - 10:21 AM

It just so happens the 10 XW is a pretty excellent DSO eyepiece in my biggest scope a very good C9.25. I suspect the same will hold true in the 11" Teeter STS on the way. No way are my 7 & 10 XWs inferior to my 12 Delos & 17.3 and 13 Ethos for DSOs or lunar-planetary! I can and do use my barlows and Powermates to match powers with all of the above. David

#42 Sarkikos

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Posted 17 May 2013 - 11:30 AM

That, or the fact that the XWs are pretty lousy large aperture DSO eyepieces compared to premium simple, low-element designs in some situations. :thinking:


But for looky-loos, and fueling goofy Siddarthic posts, XWs are splendid. But for me, the LVWs are much better than the XWs for such purposes. So even in that use case, the XWs are somewhat lacking. :winky:


You realize you're stirring the pot here, don't you, Jim? There are Brandonistas, and then there are XWsatvas.

:grin:
Mike

#43 Sarkikos

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Posted 17 May 2013 - 11:37 AM

dscarpa,

Even when barlowed my 24 Brandon when it comes to scatter bests my Delos, XWs, and such native. The darker background and special quality of the image is still there as well.


I'm not surprised that the Brandons have better scatter control than some of the more complex designs. Although according to Vernonscope, the simpler coatings are the major reason for better scatter control.

But I really think the darker background of the Brandons is due to simpler coatings. It's as if the Brandons have built-in filtering. The Brandons are FC, while the Delos, XWs, etc. are FMC. IME, XWs and Sterling Plossls have better light transmission than Brandons.

Mike

#44 Sarkikos

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Posted 17 May 2013 - 12:17 PM

Jim,

That, or the fact that the XWs are pretty lousy large aperture DSO eyepieces compared to premium simple, low-element designs in some situations. :thinking:

When I swap TMB Supermonos in for the XWs in the 16" f/5.1, for example, I gain about 5-10% (SOTP) more resolved stars on most globulars. The XWs are lovely eyepieces for casual, general purpose observing, but they don't go very deep compared even to the Ethoses or even the new Deloses, much less any premium simple eyepiece.


From what I've heard, the XW's have better light transmission than the Ethos, and are close to the Delos.

This is how Alvin Huey ranked the XW and a few other eyepieces according to light transmission, with a ZAO being the best:

ZAO > Delos > XW > Ethos

I believe he said the XW was closer to the Delos than the Ethos. In another comparo, Alvin said that the light transmission for a new Baader Classic Ortho was between the ZAO-II and the Delos!

In my own experience, when observing the Horsehead, a Sterling Plossl had the best transmission (grade A), followed by XW (B+), Brandon (B), BGO (C+), and UO VT ©.

So I wouldn't be so quick to short change the XW for DSO ... or the BCO or Sterling Plossl!

Mike

#45 dscarpa

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Posted 17 May 2013 - 12:23 PM

I like using my Brandon back to back with my cool toned widefields. They seem to compliment each other and I usually see more than just using one type. I've got a 18 BCO but haven't used it that much yet. David

#46 Sarkikos

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Posted 17 May 2013 - 12:58 PM

I only have a pair of BCO 10 for binoviewing. I'm tempted to get a BCO 18 for deep sky. I wish they came in 25mm. That might be a better Horsehead eyepiece for me than even the Sterling 25.1.

Mike

#47 ibase

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Posted 17 May 2013 - 01:15 PM

This is how Alvin Huey ranked the XW and a few other eyepieces according to light transmission, with a ZAO being the best:

ZAO > Delos > XW > Ethos

I believe he said the XW was closer to the Delos than the Ethos. In another comparo, Alvin said that the light transmission for a new Baader Classic Ortho was between the ZAO-II and the Delos!


Mike, according to Alvin, the Ethos edges out the Pentax XW in his forum post here; piecing it all together:

ZAO II > BCO > Delos > Ethos > Pentax XW

Best,

#48 junomike

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Posted 17 May 2013 - 02:42 PM

What's their FOV?



Pentax Or. SMC's are 42° FOV. I recently picked one up to fit in between my CZJ 0 - 16 and CZJ 0 - 25.
(mine was free of eyelashes!)

Mike

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#49 Sarkikos

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Posted 17 May 2013 - 06:55 PM


This is how Alvin Huey ranked the XW and a few other eyepieces according to light transmission, with a ZAO being the best:

ZAO > Delos > XW > Ethos

I believe he said the XW was closer to the Delos than the Ethos. In another comparo, Alvin said that the light transmission for a new Baader Classic Ortho was between the ZAO-II and the Delos!


Mike, according to Alvin, the Ethos edges out the Pentax XW in his forum post here; piecing it all together:

ZAO II > BCO > Delos > Ethos > Pentax XW

Best,


Yes, just to set the record straight, this is exactly what Alvin says in the thread you cite:

... and the Ethos and XW are about the same, giving the Ethos the slightest edge.



Not exactly a glowing endorsement of the Ethos over the XW's. But AFAIK there is an earlier thread in which Alvin rates the XW's as having better light transmission than the Ethos. That is where I got my information. But this is not surprising, since he says the Ethos and XW's are about the same.

So I think it'd be fairer to rate these eyepieces something like this:

ZAO II > BCO > Delos > Ethos/Pentax XW

Of course for me the point is moot, since I doubt if I'll ever buy a ZAO or an Ethos. And judging from other reports I've read from other observers, the Delos don't exactly "smoke" the XW, though many say they are an improvement.

Mike

#50 Sarkikos

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Posted 18 May 2013 - 12:35 AM

Jim,

The XWs are lovely eyepieces for casual, general purpose observing, but they don't go very deep compared even to the Ethoses or even the new Deloses, much less any premium simple eyepiece.


Even Alvin Huey, the guru of eyepiece comparos through large aperture, says that the XW and Ethos have nearly the same light transmission. According to him, the Ethos have the "slightest edge" over the XW. So it doesn't seem like the Ethos go very much deeper. Certainly not enough of a difference to disturb the serenity of an XWsatva.

Mike






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