38 replies to this topic

[Princess Leah]

I was about to purchase another 0.965 to 1.25 Inch adapter, when I came across two different kinds.

I have purchased the first one before, but I can't understand the second one. The dimensions seem wrong?

 

Thanks for your help Leah.

 

https://www.ebay.co....ZF3VMQG5NQ96QCC

 

httrkparms=amclksrc%3DITM%26aid%3D1110006%26algo%3DHOMESPLICE.SIM%26ao%3D1%26asc%3D20240305151706%26meid%3D0e98bff60619465d840dd30b97d648a1%26pid%3D101729%26rk%3D1%26rkt%3D25%26sd%3D156280469875%26itm%3D387661538441%26pmt%3D1%26noa%3D1%26pg%3D3959035%26algv%3DDefaultOrganicWebWithV11WebTrimmedV3VisualRankerWithKnnV3AndUltBRecallAndBertRecallAll%26brand%3DUnbranded%26fpg%3D0&_trksid=p3959035.c101729.m1851

Edited by Princess Leah, 02 January 2025 - 09:51 AM.

[deSitter]

These links involve a sign-in directive. Go to the item and remove everything to the right and including the first ? symbol in the link. This is a problem with copy/paste. Example -

 

https://www.ebay.co....tm/256622506618

 

The last characters should be the unique item number. Everything after that is session-specific to you.

 

-drl

[deSitter]

The second link shows an adapter I have not seen before. Are you looking for the 3270 Vixen adapter to replace the visual back on a classic scope?

 

-drl

[Russell Smith]

The second one seems to fit a 1.25" visual back to use .965 eyepieces. 

[deSitter]

This is the 1.25" visual back replacement with 36.4mm threads that works with many (NOT all) classic telescopes. In general, if there is a single focuser tube, this will work. If there is a long drawtube as in the Tasco 10TE-5, it will not thread on.

 

https://www.ebay.co....tm/296800446992

 

-drl

[andycknight]

I'm not sure what you are trying to adapt, so a few more details would help...

 

However in general... Fitting a 0.965" eyepiece into a 1.25" focuser via the use of a reducing bushing is OK. Normally this only requires about 5~10 mm of inward focus travel. (Which most focusers have)

 

However fitting a 1.25" eyepiece into a 0.965" focuser can cause problems, especially with the adapter linked to above.

Not only do you need an extra ~ 30mm of inward focuser travel for the adapter, but the bigger 1.25" diagonal needs another 10~20mm on top. (Note this can be reduced by using a Prism diagonal as opposed to a mirror type)

 

What this means is you can loose the ability to be able to focus at infinity.

 

The next issue is regarding low power eyepieces (that have field stops larger than the internal clear aperture of the 0.965" focuser - i.e. bigger than about 20mm diameter). These can vignette badly causing the outer field of the Eyepiece to darken or even completely black out.

 

The 3rd possible issue is weight... Some of the 0.965" focusers were never designed to carry the weight of the bigger 1.25" Eyepieces/diagonals.

 

Hope this helps

 

Regards

 

Andy.

[Princess Leah]

This is the 1.25" visual back replacement with 36.4mm threads that works with many (NOT all) classic telescopes. In general, if there is a single focuser tube, this will work. If there is a long drawtube as in the Tasco 10TE-5, it will not thread on.

 

https://www.ebay.co....tm/296800446992

 

-drl

Thanks. I have that one for my Prinz. I'm looking for one for a 60/700 Towa. I expect I will run out of inward focus.

[Princess Leah]

I will need to go up to the attic and check to see if it has a thread etc.

[Princess Leah]

I know from experience these tend not to have enough inward travel for the first adapter shown. 

Edited by Princess Leah, 02 January 2025 - 10:36 AM.

[CarolinaBanker]

I highly recommend buying some classic .965 eyepieces. The issue is that many vintage scopes came with outmoded designs, that were cheaply produced but even upgrading from the included Huygens and Ramsden to a Kellner or Plossl makes a world of difference.

[Princess Leah]

26mm outer diameter measured.

[Princess Leah]

Ideally you would have a 26M to 31M connector ring. Then you could remove the nose piece of the diagonal and screw the adapter in.

As it is I think I will have to use friction.

[Princess Leah]

The diagonal will hold with masking tape for the now .

 

 

Attached Thumbnails

• 

[ericb760]

Rather than an adapter, which may or may not allow you to focus, I would suggest a .965 to 1.25 diagonal where the nose piece is .965 and the eyepiece barrel is 1.25.

 

Edited by ericb760, 05 January 2025 - 12:41 PM.

[Princess Leah]

Impossible. They have become extinct in Europe. But I learned today there is not enough travel for the adapters I suggested above.

[CarolinaBanker]

Here’s what you need, a hybrid diagonal. They ship to the UK/Ireland/Germany etc.: https://www.ebay.com/itm/235634073332

[Princess Leah]

Thanks. But unfortunately that's a mirror, I need a prism 

[CarolinaBanker]

Thanks. But unfortunately that's a mirror, I need a prism 

Why? It works with refractors.

[Princess Leah]

I compared it with a mirror, wasn't as good.

[CarolinaBanker]

Prism that ships internationally, albeit 45 degrees: https://agenaastro.c...m-diagonal.html

 

90 degrees but out of stock: https://agenaastro.c...m-diagonal.html

[CarolinaBanker]

I compared it with a mirror, wasn't as good.

It might just be a bad mirror.

[Princess Leah]

Agreed, but the mirror you linked to, is unlikely to be as good as my Celestron prism which can also be collimated.

[CarolinaBanker]

Agreed, but the mirror you linked to, is unlikely to be as good as my Celestron prism which can also be collimated.

Then I’d buy some decent orthos or Plossls and call it a day, if you look around you can get decent deals.

[RichA]

I was about to purchase another 0.965 to 1.25 Inch adapter, when I came across two different kinds.

I have purchased the first one before, but I can't understand the second one. The dimensions seem wrong?

 

Side issue;  it's the best thing you can do for a Japanese small refractor or reflector.  Not that good 0.96 eyepieces don't exist, there are Taks and early Celestron orthos in 0.96, but eyepieces longer than 20mm demand a good 1-1/4 construction.  

[Princess Leah]

I think the second link I listed would work, providing the thread is the right size. I contacted the earlier, I'm doubtful I will get a reply.