Skywatcher 1.25" adapter replacement.

[Steenamaroo]

Hi all,

Beginner here, slowly getting set up with my new (to me) 200p.
I picked up a Canon 500d and T-adapter with 1.25" fitting recently.

As expected I can achieve focus with Camera > T-adapter > Scope, (image E)
but I can not with Camera > T-adapter > 1.25" adapter > Scope. (image F). There isn't enough inward travel.
The same is true with a barlow in between.

The photographs are just to show the equipment - I realise the focuser is not fully down/in? in the images.

It gets very close to focus; Another quarter inch would do it so I was thinking of buying a second 1.25" (circled Images C and F)
A low profile one would be ideal. If that doesn't exist I figure I could cut/grind a spare one down half an inch,
then drill and thread for grub screws.

Problem is I'm having trouble finding this part and am now wondering is it unique to the brand?

I suppose a low profile barlow is an option but I'd rather have universal kit than one modified piece.

I'm certain about the direction of travel required.
I actually fitted the circled part in image C into the back of its mate (same image) for testing and could achieve focus perfectly but, of course, the camera wasn't secure.

First real question here, but I've learned a lot already from reading! Thank you for this wonderful resource.

Apologies for vague or incorrect terminology. 😂

Edited November 12, 2019 by Steenamaroo

[Ruud]

That's a really long adapter. This one is just 1mm long: https://www.teleskop-express.de/shop/product_info.php/info/p4218_TS-Optics-Adapter-from-2--to-1-25----only-1-mm-length.html

[Cornelius Varley]

The only two items you need are the t-ring and the lower part in picture C.  This part should have a t-thread that matches the thread on the t-ring.

[Steenamaroo]

14 minutes ago, Cornelius Varley said:

The only two items you need are the t-ring and the lower part in picture C.  This part should have a t-thread that matches the thread on the t-ring.

Yes, I've set up that arrangement in images D+E and it works just fine.
I'd like the option of placing a barlow in-line, though.

Thanks ^.

24 minutes ago, Ruud said:

That's a really long adapter. This one is just 1mm long: https://www.teleskop-express.de/shop/product_info.php/info/p4218_TS-Optics-Adapter-from-2--to-1-25----only-1-mm-length.html

I've seen these but that's described as a 2" to 1.25".

From what I understand my Skywatcher would have come with the base piece (Image C) plus two adapters...one for 2" that I don't have one for and 1.25" that I do.
I.E. I don't think the product linked would fit directly to my base piece.

I might be wrong about that but that's why I'm here...To make sure.

Thanks for the reply.

Edited November 12, 2019 by Steenamaroo

[Steenamaroo]

For clarity, here is an image of the flanged base piece from Image C, with a tape for size reference.

 

 

[Ruud]

What I linked to is intended to replace this:

The replacement would be 1mm deep instead of 3cm, which you have now.

Alternatively, you could get a 2" nosepiece for your T-ring, if that fits in this ring.

 

Edited November 12, 2019 by Ruud

[Steenamaroo]

Ah, I see! That makes more sense.

I was hoping for a lower profile solution where the eyepiece securing grub screw would still be accessible,
but that's not the end of the world. Thanks for your help.

[Ruud]

Short adapters with grub screws exist too: you want a low profile 2" to 1.25" adapter. Google for that and you'll find plenty.

The one I linked to is really short. If you chose that one, I suppose you'd keep it on permanently.

The TV in-travel has a negative profile, but again no grub screw: http://www.televue.com/engine/TV3b_page.asp?id=23

This one is also pretty short, but is still a cm long. It has a grub screw though: https://www.teleskop-express.de/shop/product_info.php/info/p281_TS-Optics-adapter-from-2--to-1-25----2--filterthread---compression-ring.html

[Steenamaroo]

That last link looks like the chap!

I got caught up trying to figure out what the threading was on my piece circled in image C.
Didn't realise that that 2" parts were directly compatible with my gear! 😳

Many thanks, again.

[Ruud]

1 hour ago, Steenamaroo said:

Didn't realise that that 2" parts were directly compatible

That is the case normally.

But I believe that some telescopes have focusers that are neither suited directly for 2" or 1.25". These require two separate adapters, one for 2" and another for 1.25" accessories.

EDIT

Tried to find a manual, but failed. Looking at your image B I get the feeling that a 2" eyepiece couldn't go in deep enough if that opening is 2" wide at the end. I guess it is wider and that a separate 2" adapter probably came with the telescope.

Edited November 12, 2019 by Ruud

[Steenamaroo]

In image B the inner diameter at the thumb screw is 2 1/4" but the diameter deeper in is exactly 2",
so I think your teleskop-express link should do the job.

[Ruud]

Oh, I just edited my previous post.

Without a 2" adapter, anything 2" might end up crooked with the screw pushing the 2" accessory to one side in the wider section.

Do you have an adapter?

 

[Steenamaroo]

No, my scope came with only the 1.25 but it was bought used.

I had been trying to find something using the same thread shown in the circle in Image C,
but totally overlooked the fact that I could just get a low profile T2 female to 1.25 adapter, like the top half in this picture (not my picture).

Maybe that's the best plan.

Edited November 12, 2019 by Steenamaroo