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Equipment Discussions >> Binoculars

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Tamiji Homma
Carpal Tunnel
*****

Reged: 02/24/07

Loc: California, USA
Re: Kowa Highlander: New Eyepieces in the Pipeline! new [Re: Ryuno]
      #5898325 - 06/02/13 06:36 PM

Hi Heinz,

No, I didn't take photos of Kowa45 before I sent them back to Harry. When I get them back, I'll post photos.

Spring loaded ring is inside focuser. The O-ring is on eyepiece nosepiece. When you push the eyepiece into focuser, the O-ring goes in the spring loaded ring to hold the eyepiece securely in center.

You need quite bit of force to remove the eyepiece from focuser just as Kowa original eyepieces.

I couldn't come to focus to infinity but I tried closer target, a few hundred feet away. Image merged perfectly

Tammy


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Tamiji Homma
Carpal Tunnel
*****

Reged: 02/24/07

Loc: California, USA
Re: Kowa Highlander: New Eyepieces in the Pipeline! new [Re: Ryuno]
      #5929592 - 06/19/13 04:06 PM

Hi Heinz,

A pair of Kowa45s are back from Harry. Now it does come to focus to infinity

Here is photo, from left to right:
Kowa 21mm, Kowa 14mm, Kowa 9mm, Harry's Kowa45 field lens up, Kowa45 eye lens up with field lens cap on:



Closeup of Kowa45:


I'll try them later tonight.

Tammy


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Ryuno
sage


Reged: 05/09/13

Loc: Tokyo
Re: Kowa Highlander: New Eyepieces in the Pipeline! new [Re: Tamiji Homma]
      #5931038 - 06/20/13 10:41 AM

Hi Tammy

Thank you for the pictures. That's exciting. I am very curious to hear about your first experiences with them, especially for the night sky.

Did you have a chance to use them yesterday evening?

Heinz

Edited by Ryuno (06/20/13 10:42 AM)


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Tamiji Homma
Carpal Tunnel
*****

Reged: 02/24/07

Loc: California, USA
Re: Kowa Highlander: New Eyepieces in the Pipeline! new [Re: Ryuno]
      #5931161 - 06/20/13 11:55 AM

Hi Heinz,

Yes, I did first light with Harry's Kowa 45. Just half an hour early evening.
Seeing was lousy so I can't really say much from the observation beyond I can spot Cassini Division

I also did indoor test as I always do when I get a chance to try a new eyepiece. I compared the closest focal length eyepiece, Ethos SX 4.7 with Kowa 4.5.

Code:

Kowa 45 field stop 4.88mm, pseudo AFOV 62 degree
Ethos SX 4.7 field stop 8.93mm, pseudo AFOV 109 degree

pseudo AFOV = 57.3 * (field_stop/focal_length) degree



From indoor resolution test, I can't see much difference between two across the field but I do notice that Ethos SX 4.7 gives impression of higher contrast.

I will try to compare TSA102S+Amici Prism Diagonal + binoviewer against Kowa Highlander with Kowa 4.5.

To match power, I can choose:

Kowa 9mm gives 108x (with 1.19x GPC)
Delos 10, XW 10 give 97x

By the way, if you cut off filter thread cleanly, I think Ethos SX 4.7 comes to focus to infinity with Kowa Highlander. I am not planning to do it but wide AFOV is good for binoculars.

Tammy


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Ryuno
sage


Reged: 05/09/13

Loc: Tokyo
Re: Kowa Highlander: New Eyepieces in the Pipeline! new [Re: Tamiji Homma]
      #5932713 - 06/21/13 09:47 AM

Hi Tammy

Thanks for the report. Sounds interesting. What is the practical significance of pseudo AFOV? And what is GPC?

Any more observations? And how about the brightness of the eyepieces?
I think I'll wait for your results before taking a decision to purchase a set myself. I am vacillating between the 6mm (because of better eye relief) and the 4.5mm (because of higher magnification).
By the way, do you think, Harry's eyepieces can be fitted with standard 1.25 inch filters?

Hopefully soon you have better seeing.

Have a good star-filled weekend. Here in Japan it's still the rainy season and I am mostly confined to my skyscrapers. ( sigh!)

Heinz


Edited by Ryuno (06/21/13 10:29 AM)


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Tamiji Homma
Carpal Tunnel
*****

Reged: 02/24/07

Loc: California, USA
Re: Kowa Highlander: New Eyepieces in the Pipeline! new [Re: Ryuno]
      #5932866 - 06/21/13 11:48 AM

Hi Heinz,

The pseudo AFOV is calculated approximation of AFOV with zero rectangular distortion.
Well, zero RD is impossible. The P-AFOV is close enough most cases to represent AFOV, specially not too wide AFOV eyepiece.

GPC is Glasspath Corrector, Baader's Barlow lens. I usually use 1.25x GPC (measured 1.19x for most eyepieces) along with Baader MarkV binoviewer.

Yes, I observed Saturn last night. Seeing was much better. Saturn wasn't wobbling. When seeing was stable, it rendered quite nice image of Saturn. Cassini Division was well defined and I was able to spot 6 moons. It was bit hard since sky was brightened up by the Moon.

Regarding eye relief, spec says 10mm but I feel bit shorter than that. Takahashi LE 5 is more comfortable than Kowa45, maybe due to wider flat eyepiece top.

The Kowa eyepiece does not have filter thread. Due to eyepiece holder/locking design, I don't think you can use the standard filter with Kowa Highlander. I hope they design new binoculars with standard eyepiece use in mind, maybe with 88mm objective lens from their spotting scope, and flattener builtin eyepiece for the objective lens

I think Markus@APM had (has?) expensive filters fitted in objective lens thread (90mm?). I remember they cost over $1K U.S and are custom build.

About 6mm instead of 4.5mm, I think it is a good idea. Even though Kowa Highlander could go even higher power, I don't think that it is smart thing to do. I would prefer wider/brighter view with binoculars.

Tammy


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The Ardent
scholastic sledgehammer
*****

Reged: 10/24/08

Loc: Virginia
Re: Kowa Highlander: New Eyepieces in the Pipeline! new [Re: Tamiji Homma]
      #5933416 - 06/21/13 05:54 PM Attachment (29 downloads)

The Highlander can use 95mm filters over the objectives. B&H has a large selection of 95mm polarizing/ UV/ Haze filters for cameras that will fit. Good for daytime use.
Pictured here are 95mm astronomical custom made Nebula Filters. Used in the city, bright nebulae like M42 are seen with a dark background instead of a milky grey background. Only 3 stars or the Trapezium are visible with filters. All 4 are easily visible at 32x without.
Bright but small nebs like 7027 don't benefit much, its a bright tiny green pea with or without filters at 32x.
In darker, semirural skies bright nebulae like M57 or 27 become larger with improved definition. NGC 7000 is seen with detail. One night when the Helix was invisible due to haze and low altitude, it became easily visible with the filters.
The filters are good on a handful of targets and in certain situations. Not a substitute for larger aperture or dark skies. I had the filters less than a year now, have not tested extensively. When the Milky Way comes back in fall-winter thats bino time.


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Ryuno
sage


Reged: 05/09/13

Loc: Tokyo
Re: Kowa Highlander: New Eyepieces in the Pipeline! new [Re: The Ardent]
      #5935542 - 06/22/13 11:08 PM

Thank you, Ray, for the detailed info about the filters. Which one do you think would be best for me in the middle of Tokyo, where only the very brightest stars can be seen?

Best regards
Heinz

Edited by Ryuno (06/22/13 11:23 PM)


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Ryuno
sage


Reged: 05/09/13

Loc: Tokyo
Re: Kowa Highlander: New Eyepieces in the Pipeline! new [Re: Ryuno]
      #5935558 - 06/22/13 11:21 PM

Today during the day I tried to use the Highlander eyepieces on the Sky 90 Apo refractor. There was no problem with reaching focus.
Has anyone used these eyepieces at night for astronomical observations with a telescope?
How do they perform?
Heinz


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Tamiji Homma
Carpal Tunnel
*****

Reged: 02/24/07

Loc: California, USA
Re: Kowa Highlander: New Eyepieces in the Pipeline! new [Re: Ryuno]
      #5935734 - 06/23/13 01:44 AM

Hi Heinz,

Kowa eyepieces (9mm, 14mm, 21mm) for Kowa Highlander are very decent. They might not be the top notch but they are very good. I tried them with various scopes (f/4-f/11.5).

I observed Saturn using Takahashi TSA-102S + GPC 1.25x + MarkV + Kowa 9mm. I didn't do direct side-by-side tonight. I'd try when I get a chance.

However, I don't think Kowa Highlander + Kowa45 (100x) has any chance to beat TSA-102S + MarkV. When I did at 50x-ish power, it was the same. TSA-102S+MarkV won.

I think that it is good idea to stick with 50x or lower. Binoculars excel at lower/wider view

Tammy


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Ryuno
sage


Reged: 05/09/13

Loc: Tokyo
Re: Kowa Highlander: New Eyepieces in the Pipeline! new [Re: Tamiji Homma]
      #5984347 - 07/22/13 11:42 AM

A few days ago I jumped into the unknown and ordered a pair of the Siebert Kowa60 6.0mm eyepieces for the Highlander. Has anyone ever used these before?

Heinz


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Ryuno
sage


Reged: 05/09/13

Loc: Tokyo
Re: Kowa Highlander: New Eyepieces in the Pipeline! new [Re: Ryuno]
      #6003638 - 08/02/13 05:56 PM

Tammy,
Just look, what I found about using astronomical eyepiecess with the Highlander! Isn't this website a beauty. Just paste it into Google-Translate. Nothing short of sensational, in spite of the lousy translation.

http://www.geocities.jp/pureione/Hightlander.html

Heinz


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Ryuno
sage


Reged: 05/09/13

Loc: Tokyo
Re: Kowa Highlander: New Eyepieces in the Pipeline! new [Re: Ryuno]
      #6061100 - 09/03/13 01:57 PM Attachment (13 downloads)

Finally, the Siebert Optics Kowa60 6mm eyepieces for the Highlander arrived. I was very suprised about the low weight of the package, when it arrived and thought there must have been a mistake... until I opened it and found that the eyepieces are made of plastic. This is the first time I have seen plastic eyepieces. Is this the new standard?
Anyway the first impression was not favorable in comparison to the Kowa eyepieced, which are extremely solid and of a high bulid quality.
Later on the phone, Harry Siebert explained to me that he machines his eyepieces out of a special synthetic material which is light weight, yet more rigid, stronger and especially more stable than aluminium eyepieces.
They are held in the socket of the focuser by rubber o-rings. In the beginning I was hardly able to push the eyepieces in, but after I got used to it and found a few tricks given to me by Harry, things are running pretty moothly by now.
SO, how would they perform optically? I put them into use immediately, first on the night skyline of Tokyo. The picture is very sharp. Nothing to be desired here. It is rathe dark at the same time, but this might be expected considering the high magnification.
In the beginning it was impossible for me to merge the image. Butt then I found that they eyepieces were just tilted a little in their sockets. Pulling on them to both sides solved the collimation problem.

Next time I will test with real stars.
Until then best regards
Heinz


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Ryuno
sage


Reged: 05/09/13

Loc: Tokyo
Re: Kowa Highlander: New Eyepieces in the Pipeline! new [Re: Ryuno]
      #6061102 - 09/03/13 01:59 PM Attachment (25 downloads)

Next image.

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