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New 85 degree Pentax XWs on the way


Highburymark

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I read Don's write-up of the 23mm XW and concluded that I'll soldier on with my 26mm (really 25mm) Meade MWA in my quest for an ~80° long eye relief eyepiece with good correction in the 23mm to 26mm range.  If I back off a bit (maybe to 17mm eye relief) to avoid severe SAEP, I can comfortably take in 79° wearing eyeglasses with just a hint of SAEP shadows.  Pushing in hard with eyeglasses (just 10mm of usable eye relief) to see all 83° results in massive SAEP making it impossible to take in the entire FOV at once.  As Don said in his piece, some flawed eyepieces that make up for it in performance just grow on you over time.  The Meade is surprisingly well corrected and flat of field to the edge despite its usability warts.  I've never tried to judge it for EOFB or contrast.

@Don PensackHow much of the new Pentax's FOV is visible when backed off to a comfortable eye relief distance for wearing eyeglasses?  How much does SAEP intrude at that point?

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My field analysis:

https://www.cloudynights.com/topic/849945-new-85°-pentax-eyepieces/?p=12369694

and the following post as well.

If you just touch the eyecup with glasses on, but do not press, I think you will see maybe a 75° field?  I didn't analyze that,

but the field didn't get that much larger when pressing hard to see the field stop.

It also seemed a little easier in the 16.5mm than in the 23mm.

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4 hours ago, Don Pensack said:

My field analysis:

https://www.cloudynights.com/topic/849945-new-85°-pentax-eyepieces/?p=12369694

and the following post as well.

If you just touch the eyecup with glasses on, but do not press, I think you will see maybe a 75° field?  I didn't analyze that,

but the field didn't get that much larger when pressing hard to see the field stop.

It also seemed a little easier in the 16.5mm than in the 23mm.

Thanks for those two field analysis reports @Don Pensack 👍

I’ve got the 16.5mm on order, so good to hear they’re performing quite well… field curvature seems to be good, but reduction. In eye relief is a bit disappointing… although I don’t use glasses for observing (yet) 🤔

Will be following that thread, but can’t wait to try mine out, once it arrives… intend to get the 23mm too (I have the full set of 70 degree XWs as my primary set).

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  • 2 weeks later...

Out in the wild, good, must resist temptation though to try one out myself for now.
But then again 16.5 sits so well with me.
Clear sky dance now ongoing for your first light.
 

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  • 2 weeks later...

Well it's not a comprehensive report, but I've had a brief session with the XW 16.5 on my Tak FC-767DCU... unfortunately the weather really isn't co-operating yet (hopefully more clear skies during this week 🤞)... spent 30mins between in and around Orion, with some time on M42 and also M45.

Finally, I have a wide(r) field eyepiece that I can comfortably use 😀

I've tried Ethos and Nagler, all lovely but they just don't seem to work for me ergonomically (eye relief, eye comfort and handling), whereas this XW 16.5 works perfectly, and just like my existing XW and Masuyama, I am able to enjoy looking around the full 85 degrees without any issue. The adjustable eyepiece allows a perfect eye position to be dialled in and I can rest my eye gently on the eyecup and look around with ease.

It provides the same sharpness, contrast and colour too. Field curvature is still present very slightly towards the edge, but much reduced from the XW 14. The FC-76 is a very harsh test for this normally (I have no issues using these in FC-100, FOA-60 or Mewlon 180).

The only real downsides are that it's a big and (quite) heavy eyepiece (but then so are the Ethos, Naglers and indeed my XW30 and 40), and it's not inexpensive (again neither are Ethos, Nagler etc).

Given my desire for a single primary eyepiece set (all XWs), I think it's clear that I need to obtain the XW 23 and then probably reduce the set to XW 3.5, 5, 7, 10, 16.5, 23 and 40 🤔. I'm mostly using my FC-76 with the APM Superzoom these days anyway, which works wonderfully alongside the Nagler 3-6mm Zoom 

I'm very impressed that they seem to have produced a really great eyepiece and heartened to see Pentax (Ricoh) producing new astronomy products again 👍

Now I just need to the XW 23 to come into stock in the UK 😬🤣

Edited by HollyHound
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4 minutes ago, HollyHound said:

Well it's not a comprehensive report, but I've had a brief session with the XW 16.5 on my Tak FC-767DCU... unfortunately the weather really isn't co-operating yet (hopefully more clear skies during this week 🤞)... spent 30mins between in and around Orion, with some time on M42 and also M45.

Finally, I have a wide(r) field eyepiece that I can comfortably use 😀

I've tried Ethos and Nagler, all lovely but they just don't seem to work for me ergonomically (eye relief, eye comfort and handling), whereas this XW 16.5 works perfectly, and just like my existing XW and Masuyama, I am able to enjoy looking around the full 85 degrees without any issue. The adjustable eyepiece allows a perfect eye position to be dialled in and I can rest my eye gently on the eyecup and look around with ease.

It provides the same sharpness, contrast and colour too. Field curvature is still present very slightly towards the edge, but much reduced from the XW 14. The FC-76 is a very harsh test for this normally (I have no issues using these in FC-100, FOA-60 or Mewlon 180).

The only real downsides are that it's a big and (quite) heavy eyepiece (but then so are the Ethos, Naglers and indeed my XW30 and 40), and it's not inexpensive (again neither are Ethos, Nagler etc).

Given my desire for a single primary eyepiece set (all XWs), I think it's clear that I need to obtain the XW 23 and then probably reduce the set to XW 3.5, 5, 7, 10, 16.5, 23 and 40 🤔. I'm mostly using my FC-76 with the APM Superzoom these days anyway, which works wonderfully alongside the Nagler 3-6mm Zoom 

I'm very impressed that they seem to have produced a really great eyepiece and heartened to see Pentax (Ricoh) producing new astronomy products again 👍

No I just need to the XW 23 to come into stock in the UK 😬🤣

Delighted to hear you are liking the XW16.5, Gary 👍🏻

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Sounds a great eyepiece. Thanks for the report. It sounds like you think they are an improvement on the 70 degree ones? I think the size and weight would make me think twice before giving them a go, though I do like the few 70 degree ones I have.

Malcolm 

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Gary, so glad you have got to use it and report back, thank you  👍

I cannot remember if you need to wear glasses to observe or not, 
this is the one reason over an above the wonderful views of why I love the XW's.

So far the report back sounds good.



 

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12 hours ago, MalcolmM said:

Sounds a great eyepiece. Thanks for the report. It sounds like you think they are an improvement on the 70 degree ones? I think the size and weight would make me think twice before giving them a go, though I do like the few 70 degree ones I have.

Malcolm 

The XW 16.5 has the same optical qualities as the other XWs, but where it does improve things is against the XW14, which although fine in scopes f/8 and above (or my 10" f/5 Dob with Paracorr), does suffer from some field curvature in my FC-76 f/7.5

I would (now) argue that the 85 degree field (which is all visible to me) does improve the "immersive" feeling too 😀

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12 hours ago, Alan White said:

Gary, so glad you have got to use it and report back, thank you  👍

I cannot remember if you need to wear glasses to observe or not, 
this is the one reason over an above the wonderful views of why I love the XW's.

So far the report back sounds good.



 

Thanks Alan... I was very impressed indeed with this eyepiece 😀

I don't (yet) wear glasses to observe, but am aware that as age progresses, I may need to... this is another reason I'm moving to eyepieces with decent/good eye relief 🤔

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Somehow I missed this thread. The 16.5 isn't that interesting for me (I have the ES 92 deg 17 mm and 12 mm EPs). The 23 mm would offer a slightly larger FOV than the Nagler 22 mm I have, but I wonder if the switch would be worth it. The ES EPs replaced my Nagler 17 mm T4 and 12 mm T4, and proved a step up both in performance and FOV, but the 22 T4 is in my view the best Nagler I have, and just 3 deg extra is perhaps not worth it.

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1 hour ago, HollyHound said:

I would (now) argue that the 85 degree field (which is all visible to me) does improve the "immersive" feeling too

Now you've got me worried🙂 

I have invested quite a bit in eyepieces that are generally less than 55 degrees AFOV and am hoping for financial's sake I don't get the wide FOV bug 🙂.

I like my existing Pentax's (5, 10, 20) though find them too big and heavy for ease of use.

I'm not so keen on my Nagler 16. It's reasonably small and light, but I find it a little tricky to use (look through). Can't really explain why!

I do love the Tak Erfle which is light but only 60 degrees.

I have a Masuyama 32 on order and will be very interested to see how I like it. I think you have one? It seemed a good compromise between wide FOV and weight. I'm hoping it'll beat the Stella Lyra 45mm; very similar weight, very similar real FOV and the shorter FL will hopefully darken the background.

Malcolm

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2 hours ago, michael.h.f.wilkinson said:

Somehow I missed this thread. The 16.5 isn't that interesting for me (I have the ES 92 deg 17 mm and 12 mm EPs). The 23 mm would offer a slightly larger FOV than the Nagler 22 mm I have, but I wonder if the switch would be worth it. The ES EPs replaced my Nagler 17 mm T4 and 12 mm T4, and proved a step up both in performance and FOV, but the 22 T4 is in my view the best Nagler I have, and just 3 deg extra is perhaps not worth it.

I've had the Nagler 22mm, and if you like it ergonomically then there is absolutely no reason to switch... it's a great eyepiece 👍

I prefer the XWs because I just get on with the eyecup design... it's stable (doesn't adjust up/down when you handle it (both the Nagler and DeLites do), rubber (so feels warmer to the touch) and comfortable (I can place my eye against it and it holds my view steady) 😀

Optically, they're close enough to not be choosing based on that for me 🤔

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33 minutes ago, MalcolmM said:

Now you've got me worried🙂 

I have invested quite a bit in eyepieces that are generally less than 55 degrees AFOV and am hoping for financial's sake I don't get the wide FOV bug 🙂.

I like my existing Pentax's (5, 10, 20) though find them too big and heavy for ease of use.

I'm not so keen on my Nagler 16. It's reasonably small and light, but I find it a little tricky to use (look through). Can't really explain why!

I do love the Tak Erfle which is light but only 60 degrees.

I have a Masuyama 32 on order and will be very interested to see how I like it. I think you have one? It seemed a good compromise between wide FOV and weight. I'm hoping it'll beat the Stella Lyra 45mm; very similar weight, very similar real FOV and the shorter FL will hopefully darken the background.

Malcolm

Don't worry... if you're comfortable with what you have, continue to use them... I've been through pretty much every eyepiece made in the last three years, deliberately so as I like to experiment and then settle on what works best for me.

My existing XWs aren't going anywhere, except possibly for the XW14 and XW20 (but only as they will be duplicating focal lengths now),

I have the Masuyama 16 and 26 and they are both superb for clarity, contrast and colour and they're also very lightweight... they have the same FoV as the new XWs though, so for that reason only, I may be moving one or both of those on, and settle on a full set of XWs (3.5, 5, 7, 10, 16.5, 23 and 40). I have reached the stage now where I want one choice for a given focal length in my main set (keeping another small set for grab and go or travel) 👍

Edited by HollyHound
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8 minutes ago, HollyHound said:

I've had the Nagler 22mm, and if you like it ergonomically then there is absolutely no reason to switch... it's a great eyepiece 👍

I prefer the XWs because I just get on with the eyecup design... it's stable (doesn't adjust up/down when you handle it (both the Nagler and DeLites do), rubber (so feels warmer to the touch) and comfortable (I can place my eye against it and it holds my view steady) 😀

Optically, they're close enough to not be choosing based on that for me 🤔

I have never had ergonomics issues with the Nagler 22, but then I have the eye cup in the lowest position, where it seems to happily stay put. The XWs are very comfortable (I have the 10, 7, and 5 mm), and for the Delos EPs I can tighten the eye cup position well enough so they don't budge. I made my Delos 8 and 6 mm parfocal (with a ring) with the XWs, which is ideal for planetary observation, when you want to switch magnification to adjust to the conditions.

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12 minutes ago, HollyHound said:

I have the Masuyama 16 and 26 and they are both superb for clarity, contrast and colour and they're also very lightweight... they have the same FoV as the new XWs though, so for that reason only, I may be moving one or both of those on, and settle on a full set of XWs (3.5, 5, 7, 10, 16.5, 23 and 40). I have reached the stage now where I want one choice for a given focal length in my main set (keeping another small set for grab and go or travel) 

It seems like you'd want to keep the Masuyamas for the lightweight set given how big and heavy the new XW-85s are.

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4 hours ago, michael.h.f.wilkinson said:

Just read the comparison of the XW 23mm to the Nagler 22 T4 on CN, and the Nagler is safe in its place in the EP case (until ES decide to do a 22 mm 92 deg)

Right there with you.  Your eyepiece journey with the NT4s and ES-92s exactly mirrors mine.

I do have the 29mm ES-92 unicorn eyepiece.  It started out as a 12mm ES-92 missing its field (Smyth) lenses that ES sold in a large lot of warranty returns.  I've always wondered how it got in that condition.  I pieced together a couple of hard-to-find step rings to reduce its in-focus requirements from 40mm to 21mm.  If I screw my GSO CC nose piece directly into the filter threads, I can reach focus even in my Dob.

It has a lot of chromatic aberration starting not far off axis, but if you look straight at the center, it's not that noticeable.  Its much better than the vintage 30mm Kasai Super WideView 90° in this regard.  The measured AFOV remains at 93° as with the original 12mm ES-92.

It is remarkably free of edge astigmatism despite lacking its Smyth lenses.  Usable eye relief remains about the same as for the original 12mm ES-92 which I also have.  The measured field stop using photography is 48.4mm despite measuring 51mm with calipers.  The FS being well above the top of the 2" barrel allows for this.  The internal field stop is now fully accessible for direct measurement  just like in a Panoptic.

It is a hoot to pan around star fields with.  The window into space effect is full blown.  Without the Smyth lenses, there is no SAEP (kidney-beaning) at all, so holding the view is a breeze while panning, even with eyeglasses.  I've compared it to my 30mm ES-82, 30mm APM UFF, 30mm Widescan III clone, 26mm Meade MWA, 29mm Rini MPL, and the 30mm Kasai SWV 90°; and it is in a league of its own for low power, wide field panning with eyeglasses.

If ES would offer this as a product with some sort of chromatic aberration corrector instead of the Smyth lenses, it would sell like hotcakes.

Edited by Louis D
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22 minutes ago, Louis D said:

Right there with you.  Your eyepiece journey with the NT4s and ES-92s exactly mirrors mine.

I do have the 29mm ES-92 unicorn eyepiece.  It started out as a 12mm ES-92 missing its field (Smyth) lenses that ES sold in a large lot of warranty returns.  I've always wondered how it got in that condition.  I pieced together a couple of hard-to-find step rings to reduce its in-focus requirements from 40mm to 21mm.  If I screw my GSO CC nose piece directly into the filter threads, I can reach focus even in my Dob.

It has a lot of chromatic aberration starting not far off axis, but if you look straight at the center, it's not that noticeable.  Its much better than the vintage 30mm Kasai Super WideView 90° in this regard.  The measured AFOV remains at 93° as with the original 12mm ES-92.

It is remarkably free of edge astigmatism despite lacking its Smyth lenses.  Usable eye relief remains about the same as for the original 12mm ES-92 which I also have.  The measured field stop using photography is 48.4mm despite measuring 51mm with calipers.  The FS being well above the top of the 2" barrel allows for this.  The internal field stop is now fully accessible for direct measurement  just like in a Panoptic.

It is a hoot to pan around star fields with.  The window into space effect is full blown.  Without the Smyth lenses, there is no SAEP (kidney-beaning) at all, so holding the view is a breeze while panning, even with eyeglasses.  I've compared it to my 30mm ES-82, 30mm APM UFF, 26mm Meade MWA, 29mm Rini MPL, and the 30mm Kasai SWV 90°; and it is in a league of its own for low power, wide field panning with eyeglasses.

If ES would offer this as a product with some sort of chromatic aberration corrector instead of the Smyth lenses, it would sell like hotcakes.

If they did that, the mighty Nagler 31T5 "Panzerfaust" would likely go. That is one of my most used EPs, I must add. Really love it in the C8, but in the Meade SN-6 6" F/5 Schmidt-Newton and the APM 80mm F/6 triplet, it really comes into its own regarding wide-field viewing.

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28 minutes ago, michael.h.f.wilkinson said:

If they did that, the mighty Nagler 31T5 "Panzerfaust" would likely go. That is one of my most used EPs, I must add. Really love it in the C8, but in the Meade SN-6 6" F/5 Schmidt-Newton and the APM 80mm F/6 triplet, it really comes into its own regarding wide-field viewing.

The usable eye relief of the original mushroom top 30mm ES-82, which is slightly better than the 31mm NT5, is just too tight to be comfortable panning around with eyeglasses.  Both have about a 30mm diameter eye lens, which is simply not enough for an 82 degree field to be comfortable to use with eyeglasses.  It's doable, but not easy.

Here's a size comparison of my 29mm ES-92 (labelled 12 obviously) with my decloaked 30mm ES-82 and 40mm Pentax XW-R:

894532040_30mmES-8240mmXW-R29mmES_92Eyepieces.jpg.d80252ab5ee41c7fd28c6417c39cb715.jpg

I don't use the 29mm ES-92 regularly, but instead break it out occasionally to liven things up a bit.

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I have been looking at the 23mm on and off for a while and being honest struggle with my inner EP argument to find a suitable rationale to buy one.

The exit pupil argument doesn't hold water as it is far to close to the APM 24 (4.7 vs 4.9), extra FOV is 20% greater than said APM but locking up the best part of £500 for a line filter eyepiece (the APM's main use) is not selling it. Plus the fact I really do like using the APM 24, probably the easiest to get on with EP I have.

I will wait to run a comparison with 24mm APM if one comes along via a star party and see if the view persuades otherwise. 

Happy viewing folks. 

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5 hours ago, MalcolmM said:

Now you've got me worried🙂 

I have invested quite a bit in eyepieces that are generally less than 55 degrees AFOV and am hoping for financial's sake I don't get the wide FOV bug 🙂.

I like my existing Pentax's (5, 10, 20) though find them too big and heavy for ease of use.

I'm not so keen on my Nagler 16. It's reasonably small and light, but I find it a little tricky to use (look through). Can't really explain why!

I do love the Tak Erfle which is light but only 60 degrees.

I have a Masuyama 32 on order and will be very interested to see how I like it. I think you have one? It seemed a good compromise between wide FOV and weight. I'm hoping it'll beat the Stella Lyra 45mm; very similar weight, very similar real FOV and the shorter FL will hopefully darken the background.

Malcolm

As long as your scope is longer than f/8, you'll like it.

At f/5, I could see almost 50% of the field out of focus with astigmatism, so the Masuyama (which has excellent contrast, BTW) is not an eyepiece for the shorter f/ratios.

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