Having difficulty Focusing since modification

[Roog]

Dear people of SGL, I seek your help having mucked my telescope up.

Having replaced my standard skywatcher 250p eyepiece holder with Baader clicklock adapters, a 2” and a 2” to 1.25” I find that I can no longer find focus with my eyepieces. If I lock them with half the eyepiece barrel hanging out I can just about do it, but this feels a bit of a bodge and is not very secure especially  with longer eyepieces.
It was difficult to say in my fight with it in the dark last night, but it seems like it needs a minimum of 12mm extra length plus a bit so that the focuser isn’t close to ‘full out’ I am guessing but 25 to 35mm perhaps? Maybe more?

Can you please advise what I need to do to bring my telescope back to its previous focusable self, extension tube or some such thing?
 

many thanks

[Ricochet]

Yes, you need an extension, preferably one that fits between the focuser drawtube and the 2" clickclock. Which specific 2" Clickclock have you fitted? Also you should measure the height of the part(s) that you have removed from your focuser and compare it to the height of the 2" clicklock that you have fitted.

As a temporary measure, you could refit the stock Skywatcher 2" eyepiece adaptor parts and put the 2"-1.25" adaptor in that, so that you can have the ease of a clicklock with your 1.25" eyepieces.

Edited December 11, 2021 by Ricochet

[Roog]

Hi @Ricochet, thank you for your reply, I have taken the parts off and measured them as best I can and i am more confused than ever.

I have a Baader 2" Clicklock part No. 2956254 and a Baader Clicklock 2"-11/4" Reducer, part # 2956214, the idea being that I can fit the 2" part into my focuser drawtube and the 2-11/4" reducer allows me to use my 11/4" eyepieces. The difference in optical length between the original Sky watcher part and the combined effect of the Baader parts is 20 to 20.5mm.  

Trying to find a tube to fit either part is a bit of a challenge.

The male thread on the 2" Clicklock (part # 2956254), seems to be M54, if i could get a 20mm extension tube with a M54 female thread at one end and a M54 Male thread at the other?

Alternately, I could extend the 2" - 11/4" Reducer, (part #2956214) which has a 2" OD sleeve with two female treads, one measures 47.5mm (2" filter thread, M48) and the other is a T-2 Photo-thread, M42 perhaps?) again a 20mm extension would do which needs to present a smooth 2" sleeve to fit in the 2" Baader Clicklock! 

 Any help that you can give would be appreciated. Thanks 

[Andrew_B]

The ClickLock reducer has a T2 thread inside and one option would be to thread this onto something like the Baader 2" / T-2 (M48) nosepiece (2458130). I've got both items and the combination gives a measured extension of 27mm so I don't know if that's a bit too much but you'd need to check the range of focus on your scope and be sure that it wasn't creating too much back focus for some of your eyepieces.

I've not been able to find anything significantly shorter. I thought there might be a 1.25" eyepiece holder with an extension that would do the job but they all seem to be longer than the option of threading a 2" nosepiece onto the ClickLock reducer.

[Ricochet]

3 hours ago, Roog said:

The male thread on the 2" Clicklock (part # 2956254), seems to be M54, if i could get a 20mm extension tube with a M54 female thread at one end and a M54 Male thread at the other?

This is what you need to do, but you may need more than 20mm to bring any 2" eyepieces to focus. 

FLO sell 8mm and 9mm extension rings. You'd need at least two, but you could email FLO and see if they are able to source any other sizes. 

The other option would be to see if you can fit a Baader UFC system between draw tube and 2" Clicklock, but this needs careful selection of parts so you end up with the right threads either side of the UFC. 

Edited December 11, 2021 by Ricochet

[Roog]

Wow this is really messy. :0(

thankyou for your suggestions 

Edited December 11, 2021 by Roog

[Roog]

Do you think that these could work?

 https://www.harrisontelescopes.co.uk/acatalog/explore-scientific-m48-set.html#SID=1664

I assume that these could be screwed in to the base of the 2” - 11/4” reducer and the outside diameter of the extension ring being 2” would fit in the bigger of the two Baader clicklock fittings 2” ?

what do you think?

I understand that this won’t deal with 2” eyepieces, but I don’t have any of these, for the time being.

 

Edited December 12, 2021 by Roog

[Ricochet]

29 minutes ago, Roog said:

Do you think that these could work?

Yes, those would work, but you would probably also want a parfocalling ring so that you can set how far the stack slides into the focuser. However, with the cost of that set there is no real financial advantage in buying it over the M54 rings which will solve focusing with both 1.25" and 2" eyepieces.

Edited December 12, 2021 by Ricochet

[Roog]

Thanks @Ricochet I take your point, but need to find 20mm M54 ring which seem to be ilusive.

off to check what a parfocalling ring is now!

[Roog]

I have obtained and tried some M54 extension rings, optical length adds up to 18mm and whilst they do fit in the female thread of the focuser draw tube, the Baader 2" clicklock 'M54' male thread does not thread into the M54 female thread on the rings, it seems like the Baader has a different pitch M54 thread, coarser perhaps?

Can anyone cast any light on this please? 

[Andrew_B]

I had a look at the different versions of the 2" ClickLock eyepiece holder and there seem to be three M54 thread fittings. One is female and 0.75mm pitch for Bressar, Explore Scientific and Omegon (part #2956253), while the other two are male with 0.75mm pitch for TS-Optics and Skywatcher (part #2956251), and 1.0mm pitch for Skywatcher and Orion (part #2956254).

From your other posts it looks like your adapter (#2956254) has a 1.0mm thread pitch while the extension rings are the finer 0.75mm pitch. If those rings fit onto the focuser draw tube then it sounds like you need the M54x0.75 version (#2956251) of the ClickLock clamp to match.

There's a chart on this page showing the different models and thread fittings.

[Roog]

Thank you @Andrew_B  for your comprehensive explanation, I will look back through my orders to see what I have and see where I can go from here. 
 

cheers Paul