Kokusai Kohki Fujiyama HD-OR

[Mak the Night]

These seem very similar to the Astro Hutech orthoscopics and I'm pretty sure are also marketed as University Optics.

Kokusai Kohki astro goods

The 7mm is high quality and has no safety undercut or eyeguard.

Shown here compared to the AH 6mm.

The similarity to the Astro Hutech range is quite apparent. I'm guessing they are all manufactured in the same Tokyo factory.

I got a very crisp 300x lunar viewing with the 6mm AH ortho' combined with a TeleVue 2x Barlow recently. I felt that I could have got even more magnification but 300x is about the resolution limit of a 130mm aperture (60x per inch) for the Moon. I did accidentally get 337.5x when I combined a TeleVue 8mm Plossl with a TeleVue 3x Barlow instead of a 2.5x Powermate the next night. I was expecting 281x but the image of the southern highlands was surprisingly good at 337.5, if a tad darker than usual. The 7mm Fujiyama will give me 336x (approx) on my 235mm SCT.

[Putaendo Patrick]

1 hour ago, Mak the Night said:

I'm guessing they are all manufactured in the same Tokyo factory

I think the Ohi Optical Manufacturing Co., Ltd, Japan

[Mak the Night]

36 minutes ago, Putaendo Patrick said:

I think the Ohi Optical Manufacturing Co., Ltd, Japan

Thanks for the information. I've always been curious as to who the OEM is.

[John]

Nice orthos !

The body lengths of some of the Astro Hutech's are longer than the Fujiyama equivalents which changes the focal plane position by around 8mm. Optically they perform identically I found. The Fujiyama's are more or less par focal across the range wheras the Astro Hutechs are not - most match the Baader GO's but the 6mm and 18mm (if I recall right) are the same as the Fujiyamas.

I reckon the University HD orthos (current range not the earlier ones) are the same and I also found them being sold under the Edmund Optics branding as well:

http://www.edmundoptics.co.uk/microscopy/eyepieces/orthoscopic-eyepieces/2070/

We were all mourning the passing of the Baader GO's a while back but soon had a wider choice of quality abbe orthos available !

[Mak the Night]

5 hours ago, John said:

Nice orthos !

The body lengths of some of the Astro Hutech's are longer than the Fujiyama equivalents which changes the focal plane position by around 8mm. Optically they perform identically I found. The Fujiyama's are more or less par focal across the range wheras the Astro Hutechs are not - most match the Baader GO's but the 6mm and 18mm (if I recall right) are the same as the Fujiyamas.

I reckon the University HD orthos (current range not the earlier ones) are the same and I also found them being sold under the Edmund Optics branding as well:

http://www.edmundoptics.co.uk/microscopy/eyepieces/orthoscopic-eyepieces/2070/

We were all mourning the passing of the Baader GO's a while back but soon had a wider choice of quality abbe orthos available !

Thanks John. It's interesting about the focal plane position as I also thought there was a difference in size between the 7mm Fujiyama and the other AH eyepiece draw tubes. It still fascinates me that OEM's can produce runs of incredibly similar eyepiece series that are just slightly different.

I'm pretty sure this Sky-Watcher 7mm 58° UWA eyepiece is manufactured by Barsta (BST), but I’ve been informed it’s marketed with other bodies as well by different distributors, although the glass components are more or less the same.

Barsta

[nicoscy]

I had the full range of KK Orthos a while back. All of them optically excellent.

As I was (and still am) using manual mounts, I sacrificed a bit of image quality for a larger FOV and switched to binoviewers to avoid those pesky floaters.

If you have a driven mount I really recommend these, but I suggest combining the medium and long focal length eyepieces with a good barlow or powermate to obtain some more eye relief as it can be challenging (yet doable) at shorter focal lengths.

 

[Rick Towns]

I just got my Fujiyama OR-HD 6mm in the mail today! I am looking forward to giving it a spin soon.

[John]

8 hours ago, Rick Towns said:

I just got my Fujiyama OR-HD 6mm in the mail today! I am looking forward to giving it a spin soon.

Congratulations - it's a very fine eyepiece

I reckon you would have to move to really expensive exotics such as the TMB Supermonocentrics, Pentax XO's or Zeiss ZAO orthos to get better optical performance and even then the differences would be slight.

Welcome to the forum by the way !

[Rick Towns]

1 hour ago, John said:

Welcome to the forum by the way !

Thank you very much!

[neural]

Interesting, thanks. I had never heard of these EPs until my attention was drawn to Lyra Optic's closing-down sale a couple of weeks ago - I'm now the proud owner of a pair of the 12.5mm ones, which should give 188x in my C9.25 for lunar and planetary BVing. 

I know orthos usually have fairly tight eye relief, probably less than the mile or two which currently separates me from the Royal Mail depot. I will report back...