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Kowa 77 or 883 Astro 1.25 Eyepiece Adapter With Pentax XW Eyepices

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Old Thursday 9th May 2019, 14:42   #1
gcole
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Kowa 77 or 883 Astro 1.25 Eyepiece Adapter With Pentax XW Eyepieces

Any one try to use any of the Pentax XW eyepieces on the Kowas, if so with what success ? Thanks

Last edited by gcole : Thursday 9th May 2019 at 14:44.
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Old Friday 10th May 2019, 11:18   #2
Tringa45
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Hi Gwen,

Perhaps the 20 mm XW would work but I suspect you are looking for higher magnifications than 25x, and with their additional 2" barrels the shorter focal length XWs would probably require more in-focus than the Kowas could provide.

I have the astro-adapter with the knurled fixing screws for my 883 and Joachim (jring) recently drew my attention to a Kowa adapter with grub screws, which would allow about 6 mm more in-focus but which would not allow a rapid change of eyepieces.

With my adapter I can't reach infinity focus with either a 6 mm Vixen NLV or a 7,5 mm Eudiascopic. A 28 mm RKE, 19 mm Panoptic, 11 mm TV Plssl and 3,5 mm TV Nagler all work satisfactorily.

John
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Old Sunday 12th May 2019, 15:03   #3
gcole
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Thanks John for your input. I still have one of the earlier versions of the Kowa 1.25 adapters I had purchased outside the US before Kowa made them available to dealers here but I had already sold my 77 & 883 Kowas. I now only have the Pentax PR 65 EDA(last version sold in Europe) and my Nikon EDG 65. I was curious because I still have a Pentax XW20 & XW14 eyepieces and I am considering repurchasing another Kowa 77 if I could use the XW eyepieces with the Kowa adapter I still have. ..... gwen
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Old Saturday 18th May 2019, 19:46   #4
JerryLogan
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Gwen,

I have a Kowa 883, the older astro adapter and the 14 and 20 XW - will test in the next few days and let you know. I notice you have two 65mm scopes. Which do you prefer, the Pentax or the Nikon EDG? Also, would you say that the Pentax PR was a step up over the older Pentax 65 or basically the same?

Best to you,
Jerry
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Old Monday 20th May 2019, 16:15   #5
JerryLogan
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On my 883 the 14 and 21mm Pentax eyepieces do not reach infinity focus. It’s not even close with the earlier set screw adapter, a little closer to reaching infinity with the more recent, grub screw adapter. But with this adapter the end of the eyepiece actually rests on the glass window that seals the scope. In short, the 14 and 21 Pentax eyepieces are so long that they cannot completely seat themselves in the 883, much less reach infinity focus.

Best,
Jerry
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Old Monday 20th May 2019, 18:14   #6
jring
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Hi Jerry,

thank you for the insight!

Joachim
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Old Monday 20th May 2019, 22:36   #7
safaridreaming
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there seems to be mixed messages about this...

https://www.birdforum.net/showthread.php?t=327757

this post suggests there are no issues. Similarly on Binomania, a couple of users have stated that they have successfully used XW's on their Kowa's.

Not sure which adapters are being used though..

cheers
Jeelan
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Old Monday 20th May 2019, 23:38   #8
JerryLogan
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Quote:
Originally Posted by safaridreaming View Post
there seems to be mixed messages about this...

https://www.birdforum.net/showthread.php?t=327757

this post suggests there are no issues. Similarly on Binomania, a couple of users have stated that they have successfully used XW's on their Kowa's.

Not sure which adapters are being used though..

cheers
Jeelan
At one time I was obsessed with getting astronomical eyepieces into the Kowa 883 ( it was strange but spare time does strange things to a man). In the grip of madness, I had my own adapters machined and modified an 883 by removing the protective glass. This was not a big success��. But I did get the Pentax into the Kowa for an astronomical project.
In relation to Gwen’s specific question about the Kowa adapters, I can only repeat that I tried the 14 and the 21 Pentax XW and they did not come to full infinity focus. With the short(grub screw) adapter the eyepieces did not fully seat but rested on the glass plate. In this configuration it was possible to focus on a fairly wide area but not to infinity.
Best,
Jerry

Last edited by JerryLogan : Monday 20th May 2019 at 23:40.
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Old Wednesday 22nd May 2019, 00:00   #9
gcole
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Quote:
Originally Posted by JerryLogan View Post
Gwen,

I have a Kowa 883, the older astro adapter and the 14 and 20 XW - will test in the next few days and let you know. I notice you have two 65mm scopes. Which do you prefer, the Pentax or the Nikon EDG? Also, would you say that the Pentax PR was a step up over the older Pentax 65 or basically the same?

Best to you,
Jerry
Hi Jerry , Thanks for that info on the Pentax XW - 14/20 having a problem focusing completely on your Kowa 883. I think the Kowa 77 has the same focal length & if I were to buy another Kowa it would be the Kowa 77. If both have the same focal length ? Would the Pentax eyepieces act similar when mounted with the Kowa adapter on the smaller Kowa. Answering your question comparing the Pentax 65 PF to the now discontinued PR 65 ..... the main difference is the PR has a much more robust build quality along with a fine tune focus wheel which helps get a nicer sharp/clear image. As I stated on a post I wrote about my thoughts when I unboxed it originally I thought man this is a PF 65 on steroids compared to the PF builds thinner rubber armor and overall size having a beefier foot pad & more robust locking collar. As to the optics it was to my eyes just as sharp/clear as to all my previous PF 65 scopes I owned. My opinion of the Nikon EDG 65 compared to the Pentax PF/PR ...... the Nikon EDG outperforms the Pentax in all categories except size & weight. At least in the 65mm class past & present its hard for me to imagine any other scope beating it optically, its build quality or any of its many outstanding user friendly high quality eyepieces which can be used with EDG 65. One last thing .. price wise the little Pentax 65 PF/PR is hard to beat with its ability to use most 1.25 eyepieces making it optically a cracker of a scope.
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Old Wednesday 22nd May 2019, 15:21   #10
gcole
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Quote:
Originally Posted by JerryLogan View Post
On my 883 the 14 and 21mm Pentax eyepieces do not reach infinity focus. Its not even close with the earlier set screw adapter, a little closer to reaching infinity with the more recent, grub screw adapter. But with this adapter the end of the eyepiece actually rests on the glass window that seals the scope. In short, the 14 and 21 Pentax eyepieces are so long that they cannot completely seat themselves in the 883, much less reach infinity focus.

Best,
Jerry
Jerry just to be sure ..... your Pentax 21 is the XL version & not the Pentax XW20 right ?
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Old Saturday 8th June 2019, 00:05   #11
gcole
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[quote=JerryLogan;3851434]
In relation to Gwens specific question about the Kowa adapters, I can only repeat that I tried the 14 and the 21 Pentax XW and they did not come to full infinity focus. With the short(grub screw) adapter the eyepieces did not fully seat but rested on the glass plate.
Hi Jerry,
Jerry .... after thinking more about your quote I slipped the Kowa Astro adapter the one with the short grub screws over the Pentax XW20 eyepiece just to see how much of the eyepiece barrel was left sticking out past the end of the adapter and it made me think about the time I had shorten the length of a Pentax XW20 1.25 barrel length by simply using a small hand held copper plumbing tube cutter. Its simple/quick with a accurate clean cut. There is a few millimeters that can be cut off the end of the XW eyepiece 1.25 barrel before one touches the inside retaining ring for the next inside lens element. I do not remember any of the eyepiece port depths on either of the 77 or 88 Kowas , but maybe just this simple shortening of the eyepiece barrel which by the way does not effect its use again in any other scope port other than removing the eyepiece ability to have a Barlow lens attached. Doing this maybe it would allow the Kowa eyepiece with the adapter to seat flush and come to focus .
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