Whats this part called please ?

[Dan13]

hi can anyone advsied what term would be used to describe this piece? 

It attaches to my 127 mak and I would like to swap it out for a compression fitting one. 

Altair sent me a diagonal but it was two big so going for the 1.25 diagonal and would like it to slot into a compression fitting.

 

Many thanks 

Dan 

[Robindonne]

A visual back

[JamesF]

I'd call that the visual back.

James

[JamesF]

Crossed posts :)

James

[Robindonne]

And unfortunately some maks have uncommon threads.  So either an adapter from mak to sc or just use only mak dedicated stuff

[sputniksteve]

How old is your Mak?

[JamesF]

Don't think it can be that old, judging by the colour.

James

[Dan13]

1 minute ago, sputniksteve said:

How old is your Mak?

not old to me but its the black one so im guessing a fair bit old?

[Dan13]

Just now, JamesF said:

Don't think it can be that old, judging by the colour.

James

its the black one mate not the green black and white if that helps

 

[Robindonne]

Just measure the thread diam.  I have the black and white one.  With a black dovetail.  And still got that mak thread instead of sc thread

[Dan13]

1 minute ago, Robindonne said:

Just measure the thread diam.  I have the black and white one.  With a black dovetail.  And still got that mak thread instead of sc thread

Thanks, yea i did and I still got sent the wrong diagnoal 😅 now I know what its called ill imagine I can find more info on it. 

[sputniksteve]

Does this thread offer any helpful suggestions? 

 

[Dan13]

8 minutes ago, sputniksteve said:

Does this thread offer any helpful suggestions? 

 

thanks im just checking out 365 astronomy as they have a fair few adapters, just cautious of the wrong one being sent again so ill message Zoltan  

[JamesF]

The existing visual back has a T2 male thread I think.  It might be possible to fit something like this to it:

  https://www.365astronomy.com/Visual-Back-T2-to-1.25-with-additional-T2-male-thread-SHORT-version.html

That seems the simplest option.  Alternatively you could convert the thread on the back of the Mak to SCT and then look for an SCT compression visual back, but there don't seem to be many of those that are 1.25".

James

[Dan13]

24 minutes ago, JamesF said:

The existing visual back has a T2 male thread I think.  It might be possible to fit something like this to it:

  https://www.365astronomy.com/Visual-Back-T2-to-1.25-with-additional-T2-male-thread-SHORT-version.html

That seems the simplest option.  Alternatively you could convert the thread on the back of the Mak to SCT and then look for an SCT compression visual back, but there don't seem to be many of those that are 1.25".

James

Thanks, i have one of them adaptors and its two small! after searching a little it looks like this is a common issue, im waiting for altair to get back to me about the diagonal they sent as they were sure it would fit (it doesnt) and id like to grab there 1.25" one like i was going to in the first place.

 

I can however fit the item you linked to the end of the part in the picture i took, that would give me a compression fitting but not sure if that will effect any focus at all??

[Robindonne]

1 hour ago, Dan13 said:

Thanks, yea i did and I still got sent the wrong diagnoal 😅 now I know what its called ill imagine I can find more info on it. 

Ah i see the problem.  You use the wrong scale on the tape😅

[JamesF]

16 minutes ago, Dan13 said:

I can however fit the item you linked to the end of the part in the picture i took, that would give me a compression fitting but not sure if that will effect any focus at all??

That's what I meant   Leave the visual back on the OTA and then fit that adapter to the male thread on the end of it.

You should still be able to get focus.  Maks and SCTs focus by moving the focal plane to where it's in focus (by moving the primary mirror) rather than moving the eyepiece to where the focal plane is.

James

[Dan13]

1 minute ago, JamesF said:

That's what I meant   Leave the visual back on the OTA and then fit that adapter to the male thread on the end of it.

You should still be able to get focus.  Maks and SCTs focus by moving the focal plane to where it's in focus (by moving the primary mirror) rather than moving the eyepiece to where the focal plane is.

James

Perfect, thank you ill use that then and i get the other diagonal sent. Thank you for your help