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Eyepiece and adapter questions. (1 Viewer)

Boxlock

Member
United States
I have a Kowa 663, and TE-17 LER eyepiece, and was wanting a wider FOB, the TE-14 WD is $300, but I already have an assortment if 1.25" astro eyepiece, does anyone make an adapter that will allow use if 1.25" astronomy eyepieces in a Kowa 660 series, or conversely, Kowa Eyepieces in astronomical refractors?
 

jring

Well-known member
Hi,

an 1.25" astro EP with the 1.25" barrel attached will not fit into a small body Kowa as the bayonet is too narrow. If you can unscrew a 1.25" barrel w/o glass in it, an adaption might be possible.

Just tried my Expore Scientific 16mm 68 deg w/o the barrel hand held to my 613 - nice views at 26x and with a 2.6 deg or 50/1000m true field and comes to focus at infinity with lots of travel beyond.

But you will have to have an adapter made or 3d-printed.

Joachim
 

Boxlock

Member
United States
That's kind of what I was afraid of, it didn't look like it would fit or smaller field stop would stop down the AFOV of widefield eyepieces like my Pentax and TV naglers. What a shame they did not design these nice scopes to accept standardized eyepieces.
 

GeorgeL

Well-known member
That's kind of what I was afraid of, it didn't look like it would fit or smaller field stop would stop down the AFOV of widefield eyepieces like my Pentax and TV naglers. What a shame they did not design these nice scopes to accept standardized eyepieces.
Main reason I purchased Pentax spotting scope bodies only (65mm & 80mm) so I can use most all my Pentax XW and Explore Scientific eyepieces directly on them, no adapters.
 

jring

Well-known member
That's kind of what I was afraid of, it didn't look like it would fit or smaller field stop would stop down the AFOV of widefield eyepieces like my Pentax and TV naglers. What a shame they did not design these nice scopes to accept standardized eyepieces.

Hi,

the AFOV of an EP and the field stop are not really directly related. What does depend on the field stop diameter and the objective focal length, is the maximal TFOV possible.

As for why most scopes don't accept 1.25" astro EPs - I guess it is a mixture between customers demanding waterproof scopes (which is not the case for most astro EPs and especially not the way they are usually mounted) and the manufacturers wish to sell their EP series...
Of course, if an EP is designed for use with a specific series of scopes, problems like field curvature can be easily corrected in the eyepiece design too.

Joachim
 

Boxlock

Member
United States
Guess I can't complain, I have a Vortex Razor that I love, but wanted a second spotting scope so I could have one on the benchtop, and one on a tripod for scoring.I didn't have thw money for a new Vortex Razor, and didn't care for the redesign of the Gen-2, So, I bought a used TSN-1 on eBay, but when it arrived, it needed cleaning and repair, sent it in to Kowa, they sent me a bill for the repairs, I paid it, they completed the repairs, and shipped it back, and it vanished in transit. The shipper paid the claim to Kowa, and Kowa agreed to send me a new 663m. I was pretty excited to get it, and it does the basic things I needed it to do. I was just hoping to get a little wider FOV and flexibility from it without spending too much.
 
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