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Best way to gain rotation with AP standard focuser

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#1 wormstar

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Posted 13 October 2019 - 03:37 PM

I have a very nice example of a D+G scope with the standard Astro Physics(non-rotating ) focuser. As I use a Bino viewer , I am frequently having to loosen the diagonal screws to rotate the Binos, which is a  pain in the dark, I’m never sure how far the AP Maxbrite diagonal is inserted. I have had several Feathertouch focusers, but the AP is practically new and buttery smooth, so I rather not replace it.
 

what’s a good solution to add rotation on the draw tube? Baader click-lock? Do they make one that’s captured? (Allows rotation, but can’t fall out in the dark)

 

I figured this has come up before

 

thanks for any help

 

Clear Skies

Keith in Ct


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#2 wormstar

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Posted 14 October 2019 - 06:59 PM

Nothing?



#3 Don Taylor

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Posted 14 October 2019 - 10:37 PM

I'm not aware of any simple, inexpensive way to do this but it can be done. I have no experience with the A-P focusers and don't use binoviewers but I do use both Baader ClickLocks and QuickChangers.

 

I'm not aware of a captive ClickLock. It takes two hands to rotate the diagonal but it is much better than fiddling with 3 thumbscrews. I use a ClickLock on my VMC200L just for that purpose. But I repeat - it is not captive.

 

 

For adding captive rotation I use both the standard and the HD versions of the T2 QuickChangers between the focuser and diagonal to provide a rotating feature.  They are captive - although if you loosen them too much they will separate.  I use them with the Baader T2 prism and T2 BBHS diagonals. Loosen slightly, rotate, snug back up. Works great. If you don't mind a 35mm aperture restriction the simplest way is to convert to a T2 diagonal + Quickchanger + 2" nosepiece. I understand some binoviewer users then attach the (Baader?) binoviewer to the T2 diagonal with another quickchanger.  I use a 1.25" eyepiece clamp. You can also use a 2" eyepiece clamp on a T2 diagonal (Clicklock)

 

 

Another way is to assemble a rotating section from a quickchanger: https://www.baader-p...6a-and-07).html plus a 2" nosepiece: https://www.baader-p...2-part-16).html plus a 2" clamp to hold the diagonal: https://www.baader-p...ece-clamps.html. This will require about 2" of in-focus due to the length of everything.   On the order of $300 for the pieces This has a clear aperture of about 37mm.

 

 

 

If you want a larger clear aperture Baader does make a 68mm version of their QuickChanger (68mm Zeiss thread) but very expensive. The US dealers don't seem to stock it either.  This would work with 2" diagonals. Clear aperture will be limited by your diagonal.

 

The two pieces are: https://www.baader-p...lamp-only).html  and  https://www.baader-p...).html?___SID=U.

 

To these two pieces you would also need an adapter to the A-P focuser. maybe one of these (I don't know): https://www.baader-p...).html?___SID=U or https://www.baader-p...).html?___SID=U  and also a 2" eyepiece clamp to grip the diagonal.

 

If you are willing to change diagonals, and need 2" then Baader offers a version of their clicklock diagonal for use with the 68mm thread quickchanger: https://www.baader-p...ad-(zeiss).html so you could skip the 2 inch eyepiece clamp.

 

You can also convert the 2" Zeiss prism and BBHS diagonals using yet another adapter.

 

All these pieces using the 68mm Quickchanger are very expensive. 

 

 

 

Sorry for the long answer - I wish I knew of a simpler solution.  Hopefully someone else will know of a better solution.


Edited by Don Taylor, 14 October 2019 - 10:39 PM.


#4 wormstar

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Posted 20 October 2019 - 10:51 AM

Don- thanks for the very detailed reply, sorry it took so long to respond, CN is not playing well with Tapatalk and I never saw the reply.

i need to digest your solutions and contemplate what I really need, I have the 35mm T2 Baader diagonal , currently with just the 1.25 nose. My Denk Binos only have a 1.25 nose and maybe I should just stick with 1.25, vice the AP maxbright

 

thanks again, great reply! 



#5 Don Taylor

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Posted 21 October 2019 - 07:03 PM

You are very welcome!  Let me know how this works out. 



#6 gnowellsct

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Posted 22 October 2019 - 06:04 PM

I don't get it.  You insert the diagonal all the way and then tighten the screws.  The idea is to "set the drag" so that there is enough friction to hold what needs holding--even binoviewers--and yet you can rotate the diagonal in the scope.  If the drag is really tight attention must be paid to the visual back to make sure it doesn't rotate.  (I cheated and added a drop of loctite to the visual back--it's the kind that is removable)

 

The diagonal itself has a bevel.  If the compression ring (ADA2003A) is adequately tightened, it will be narrower than the bevel, and even if the setting is so loose the diagonal rotates freely the diagonal itself cannot fall out, since the nose of the diagonal is fatter than the beveled part.  

 

ADA2003A in action--I spec'd this as what I wanted on my FT and paid the $$ to make it happen, as I don't think the FT equivalent is as good (look at those nice fat screws and the sturdy thickness to the part.)  So let's be clear that even though you're talking about an AP focuser and I'm attaching a pic of an FT, this particular FT has the same visual back hardware that you have AFAIK.  I have standardized all my scopes on this set up.  

 

I don't know if it helps but here's a pic.  The solar gear is roughly equivalent to a bino in weight and leverage.

 

Greg N

 

cff focuser close up with solar - cn size - edit.jpg


Edited by gnowellsct, 22 October 2019 - 06:07 PM.



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