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ZEISS DTI thermal imaging cameras. For more discoveries at night, and during the day.

Kowa TSN1, TSN3 Baader Hyperion MK IV zoom (1 Viewer)

jrp jr

Outcome first. This did not work for me and looks doubtful for others .

I was enticed by the customer photos on Baader’s site that showed a TSN2. Also, I found at least one post here that claimed success. This turned out to be the source of the photos on the Baader site. There were also photos of other kowas who share the same threaded outer mounting ring. Baader lists an adapter ring for this purpose.

I corresponded with Baader tech support to try and work out the details. Three problems arose.

1. The nose on the zoom has a plastic protective sleeve. Baader seemed to think the removal of this sleeve would allow the eyepiece nose to pass the bayonet. It does but it is so tight even the most careful hands scratched the zoom nose quite a bit. Ok, a lot. I understood this quickly and took the risk.

2. Neither of the supplied spacing rings are correct for these scopes. I carefully made my best measurements first of scopes and eyepiece. The Telescope ring places the eyepiece nose too far from the prism. The spotting scope ring would, if allowed to, cause the eyepiece nose to touch the prism.

With Delrin and a lathe I made a couple of spacers to place the eyepiece nose within 1 mm of the prism. This was not close enough. Then I made a threaded ring that allowed me to approach the prism at a calculated rate. On one scope this went wrong and I actually touched the prism as could be felt with gentle rotation of the zoom to the 8mm mark. This places a tiny piece of the nose extended beyond the rest and slightest resistance was felt prior to the 8. This was contact. No harm visible or in view later, luckily.

3. On the Tsn1 the outer 25%, or maybe more of the field of view was out of focus. Not good enough. I got the Tsn1 to focus to 300m and no further with still blurred edges. The Tsn3 was clear edge to edge but only was able to focus to 100-150 meters. Almost, but does not fit my use.

The wider view in the tsn3 was very nice with a ~150m focus limit. The diameter interference fit would make this eyepiece suitable, if it worked, only to be left on and not changed with other eyepieces. It does not work and I have posted this to prevent others from taking the bait and wasting time and money. If you jumped right in with the supplied spotting scope spacer ring you could easily damage your scope.

In the end Baader Tech support commented they cannot go to the mechanical limits of the Kowa. Understood and thanks for your brochure with this series of scope on it. I suspected it was a risk.

All is not lost, The BHZ transforms my Celestron Regal M2 80. Wider and very nice with minimal focus changes required compared to the Celestron zoom. The BHZ accepts filters or a lens from a barlow on the nose. I tried a cheapo lens from a 2x barlow that I’m guessing yielded 1.4x. That worked and was sharp so it wasn’t a total loss.

On to SDL v3, only back ordered a year. JP

thank you very much for your report - very helpful!

Edit: reading the title helps - it was the Mk. IV...

I'd still love to know if anyone has got this eyepiece to fit onto the 663 and get the full focus range?

Whilst I love the scope with the 30x wide EP I'm becoming increasingly aware of how average the image is at 60x when using the zoom. If the Baader works then it might stop me from curiously checking optics websites for any special offers on the 883.....
Tried this on a third body. Learned some of these bayonets have a larger ID, later ones I suppose. Another Tsn1. Passed the bayonet easily this time. However, is was a model with the window (later 173xxx sn#) and the BHZ nose will not pass the smaller diameter of the window channel.

Chris , if you want to try it on your 663 I would say be prepared for failure and have a backup plan for your new Baader zoom since you are likely to scratch its nose up trying this. You will also need the $45.00 adapter to fit on the neck of your scope. Not much use for that if it does not work. If it works it would be really nice, a bit huge maybe on a 663. JP
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