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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, 15:42   #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 15:44.
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Old Friday 10th May 2019, 12:18   #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, 16:03   #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, 20:46   #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, 17:15   #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, 19:14   #6
jring
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Hi Jerry,

thank you for the insight!

Joachim
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Old Monday 20th May 2019, 23:36   #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 Tuesday 21st May 2019, 00:38   #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 : Tuesday 21st May 2019 at 00:40.
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Old Wednesday 22nd May 2019, 01:00   #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, 16:21   #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, 01:05   #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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Old Tuesday 19th November 2019, 23:16   #12
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Good news!

I bought a TSN-883 this summer when B&H ran them on a one day sale for $2200. I shipped it to a friends house down here in Florida to evade the sales taxes in Colorado where I was spending the summer. I've got it now and I bought all three astro adapters that B&H sells for it. I have both Kowa's; the one with the knurled screws and the one with the set screws. I also have one with set screws made by Alpine Astronomical. I don't see any significant difference between the two set screw adapters.

I have 5 eyepieces; the Pentax XW10, XW14 and XW20 and the Baader Planetarium Hyperion 17mm and 21mm.

All three XWs work beautifully with the knurled screw adapter but the Hyperions don't. The Hyperions do work with the set screw adapters. On my first try, the XWs did not work with the set screw adapters. The problem turned out to be that the Kowa adapter with the knurled screws has threads the entire length of the adapter and the two adapters with the set screws just have threads at the top of the adapter so the threads were not engaging the threads in the 883. I solved that problem by sliding the adapters part way down the XW's barrel.

If you are just going to use XWs, I would get the knurled screw adapter. It makes switching eyepieces the easiest. If you just have one XW, I would get the Kowa set screw adapter.

I don't know why this worked for me and not for some other people. Perhaps there has been some changes to the scope or adapters over time? I haven't checked infinity focus on the moon yet, but I could focus on a distant midrise condo building. That's as far as I would ever need for birding.

At any rate, I'm psyched up about using the my fixed power eyepieces on the TSN 883. So much so that I ordered a Noblex (formerly Docter Optics) 12.5mm UWA. The Noblex has an 84 deg AFOV and 18mm of eye relief. It's getting rave reviews. If it works on the Kowa, it could be spectacular. It will be here on Saturday so I'll let you know if it works.

I'll have time on Thursday to use the XWs in the field. I'll report back on that too.

Mark

Last edited by BinoBoy : Tuesday 19th November 2019 at 23:24.
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Old Sunday 24th November 2019, 17:03   #13
JerryLogan
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Mark,

Did you get the Noblex? Any results?

Best,
Jerry
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Old Sunday 24th November 2019, 17:51   #14
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I went out Thursday and briefly tried out the XWs and Hyperions. They all did great. I was surprised at how good the Hyperions are.

The only bad news is that the XWs are not obviously better than the Kowa 25-60 zoom, at least at low mag. The XW10 may be better than the zoom at 50X, but finding the target at 50X is not easy. I was considering looking for a used XW7, but now I'm not sure I can find a bird with it.

So, if you want a cheaper alternative to the Kowa 25-60, an XW with an astroadapter is a good option.

The Noblex required a signature and I wasn't here when they came yesterday, so I have to wait until Monday. That stinks because today would be a perfect time to try it out. I've got high hopes for it. It's a lot more expensive than an XW and the reviews are enthusiastic.

Mark
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Old Monday 25th November 2019, 21:20   #15
mayoayo
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There is a baader astro adapter for the 883, made for the baader zoom....
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Old Monday 25th November 2019, 22:08   #16
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More good news!

I got the Noblex this morning and I was relieved to find that it works great with the Kowa. It doesn't work with the knurled screw adapter but it does work with the set screw adapters.

The Noblex advertises 18mm eye relief but it appears to be less than that. The eyepiece came with the eye cup folded down in half. I could almost see the entire image circle. I discovered that I could fold it down a little further by stretching the eye cup over the base of the eye cup. That allowed me to just barely see the field stop. Based on past experience with the Nikon eii 8x30, whose usable eye relief was measured by a forum member, I would say the Noblex has about 13mm of usable eye relief.

The optical quality seems comparable to the XW20 and XW14. It does give an IMAX view of the world though. At first, I was a little concerned about the depth of focus. You need a very delicate touch on the fine focus knob to get exact focus. But, I tried the Kowa 25-60 at 40X and it is about the same. I got more used to it after using it awhile.

The other good news it that I tried the Noblex on my Pentax PF-65 ED II angled and it works fine on it too.

The only disappointment is that the optical quality is still not noticeably better than the Kowa 25-60X. I've been a photography nut since the 70s. Back then fixed focal length lenses were dramatically better than zooms. But over time the zooms have caught up. The best zooms now deliver optical quality as good as any but a few fixed focal length lenses. It looks like we are approaching that point with spotting scopes now. The Kowa 25-60X is the best zoom eyepiece I've tried. The only big advantage of the Noblex is it's spectacular apparent field of view.
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