7 replies to this topic

[joew94th]

I just bought an old orange tube C8 Celestron SCT. It came without eyepieces, but I have a few I use on my Teleview Renaissance. I also just ordered a Celestron zoom eyepiece for general viewing. The scope has finder scope which is also missing it's .965" eyepiece. Does anyone have any recommendations for sources and focal length? Given it's purpose I assume the longer the better. This finder scope is a bit bigger than the small orange ones that I was accustomed to seeing.

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[T1R2]

A lot of times they will only focus with the supplied EP, because of FL,whether or not it has a diagonal and the crosshair EP has a field stop at the bottom next to the cross hairs for them to be in focus, so it can be a challenge finding the right EP, mine will not focus any EP except the one that was made for it, it seemed to be a 25mm .965, now if your model telescope with finder was made over several yrs you might have luck finding the exact EP if you look hard enough, you might have to buy the entire scope, but can always be used for spare parts. 

[therealdmt]

Could try these (only go up to 20mm): https://www.surpluss...item/l3999.html

 

Seibert makes new ones, but also seemingly only up to 20mm: https://www.sieberto...-eyepieces.html

 

If you do a Google search on "0.965inch Telescope Eyepiece SR4/H6/K6mm/H12.5/K16/H20/K25mm with Filter Thread Astronomical Telescope Eyepiece Accessories", you’ll get search returns from AliExpress and eBay that sell a set that includes a 25mm Kelner for not too much money (~ $29 on eBay)

 

Not sure if that’s what you’re looking for though

[quilty]

20mm is an appropriate ep length

[Jon Isaacs]

20mm is an appropriate ep length

 

For a 0.965", the maximum field stop possible is smaller so 20 mm is long enough 

 

I'd contact Bill Vorce at the Telescope-Warehouse.com and see if he has any.

 

Jon

[SeattleScott]

Honestly I would be tempted to just buy a new finder (and possibly bracket). You can mess around trying to find a cheap eyepiece, and possibly extender or diagonal, to make it work. But it might take weeks to get it sorted out. And even then, you won’t be getting the max FOV. You could just buy something new (or used but modern) and likely get a wider view, and not have to worry about what parts you need to make it work.

[Marcus1]

I had the same experience and after wrenching the neck several times I bit the bullet and ordered a right angle finder scope.

[SporadicGazer]

I don't know if they'd work, but an orthoscopic Plossl or a Kelner in 24.5mm (0.965") barrels are available from Amazon Japan:

 

OR20 (Plossl):

https://www.amazon.co.jp/dp/B01BIQD7T0

 

K25:

https://www.amazon.c...n/dp/B01BQ0BPCE

 

either is $44 with shipping (according to today's exchange rate.)

 

PS- you'd need to look at the other thread on adding crosshairs if you want those too.