Telescope adapter

This topic has 10 replies, 4 voices, and was last updated 5 January 2018 at 21:58 by Stephen Paterson 1.

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4 January 2018 at 16:23 #335311
Stephen Paterson 1
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@stephenpaterson1
Hi,

Apologies in advance if this is not the correct forum but I'm looking for someone in the UK who can make a specific telescope adapter for me and wonder if any of the forum members could kindly help.

I need to confirm the measurements but it would be a small metal tube about 10mm long with an M71 female thread on one side and a male T2 (T-adapter) thread (M42 x P0.75) on the other. As I say, I'll need to measure it up first but these are just guidelines for now.

There are no adapters online for this although it could be possibly done by attaching three or so adapters together but this would be too long for my needs. So I'm thinking a single adapter would be better.

Can anyone help or point me in the right direction please?

Best regards,

Steve
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4 January 2018 at 16:23 #33131
Stephen Paterson 1
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@stephenpaterson1
4 January 2018 at 19:01 #335344
Bob Mc
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@bobmc91481
Hi Stephen..

I had a similar problem with focussers I bought from China and I know how frustrating it can be…

what I don't understand is that you say one end of a 10mm tube is 71mm internal diameter and the other is a 42 mm male external diameter…?

My suggestion is that if you can buy the tubes with the threads cut in them, could you not cut each tube up and somehow fit them together which is a lot easier than cutting threads.

…Bob..
4 January 2018 at 19:22 #335347
Stephen Paterson 1
Participant
@stephenpaterson1
Hi Bob and thanks for your reply.

The 10mm part would be the length of the tube. One end would have a 71x1mm female thread and the other would be a t2 (42×0.75mm) male thread. The 71mm end would screw onto the back of the telescope and t2 end would accommodate a number of heavy accessories like a binoviewer or a camera system.

The weight of the accessories would need the adapter tube to be robust with no looseness or flexure otherwise they could fall off or become misaligned to the optical path. So the adapter would need to be a single tube I'd say.

There are lots of adapters available but none have the threads I need. I could stack about three together but that would be too long and make it more difficult to find focus using binoviewers.

So I'm hoping someone can make one for me. I don't know if this the right site so I'm open to suggestions.

Thanks,

Steve
4 January 2018 at 20:05 #335354
Bob Mc
Participant
@bobmc91481
Hi Stephen…

I have cut similar threads for my binocular telescope … see pic below..

It would have been much easier to have a single larger diameter reflector and the Binoviewer … believe me its a better option than a binocular scope!

To make the adapter would require machining a piece from the solid or better still a circular pipe fitting… will have a scout round in me junk box…but I am not saying I will make it for you …

Will let you know tomorrow.

rgds…Bob…
4 January 2018 at 20:09 #335355
roy entwistle
Participant
@royentwistle24699
Steve You should have a message in your in box

Flashing letter on green line at top of page

Roy

Edited By roy entwistle on 04/01/2018 20:10:59
4 January 2018 at 20:39 #335359
Stephen Paterson 1
Participant
@stephenpaterson1
Thanks Bob and you have a nice set up there. You'll certainly know all about optical alignment.

Regards,

Steve
5 January 2018 at 12:19 #335433
Bob Mc
Participant
@bobmc91481
Hi Stephen..

had a look for anything I could adapt but have nothing suitable… will keep an eye open for you..

rgds..Bob.
5 January 2018 at 17:52 #335504
Stephen Paterson 1
Participant
@stephenpaterson1
Thanks Bob and much obliged.

Best regards,

Steve
5 January 2018 at 19:36 #335522
John Haine
Participant
@johnhaine32865
Steve, sounds like an ideal job for thread milling to me…. It needs a drawing. If the tube is 10mm long, how long are the projections with the M71 female (inside) and M42 male (outside) threads? What material?
5 January 2018 at 21:58 #335545
Stephen Paterson 1
Participant
@stephenpaterson1
Thanks for all your replies and private messages.

I've had a couple of offers for assistance for which I am truly grateful.

I now need to sketch up the measurements.

Thanks all and for a great forum.

Best regards,

Steve
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