Jump to content

  •  

CNers have asked about a donation box for Cloudy Nights over the years, so here you go. Donation is not required by any means, so please enjoy your stay.

Photo

Alternative to finderscope rings?

  • Please log in to reply
13 replies to this topic

#1 barsuda

barsuda

    Lift Off

  • *****
  • topic starter
  • Posts: 18
  • Joined: 27 Aug 2018

Posted 18 April 2019 - 11:29 AM

I am currently working out the details of mounting dual scopes. Where I need advice is how to align 2 scopes without using finderscope rings?. Currently the 2nd smaller scope is a modified ST80 weighing in at 5 lbs, though over time I may want to go larger. The closest I have found to a technical solution is the various guide scope mounts supplied by ADM, Skywatcher, Astromania etc. For example:

 

https://www.amazon.c...t/dp/B0734NDZVH

 

The guidescope mounts are likely effective but rather expensive solutions and I am not clear which  of these are the best bang for the buck? Before I go that route I want to ask if anyone has found other ways to align 2 scopes. What comes to mind is possible off-label gear from places like photography, construction etc. I would also be interested if anyone has devised their own custom solution as I also have some ability to do simple fabrication.

 

All options would be appreciated smile.gif


Edited by barsuda, 18 April 2019 - 11:31 AM.


#2 scadvice

scadvice

    Apollo

  • *****
  • Vendors
  • Posts: 1226
  • Joined: 20 Feb 2018
  • Loc: Lodi, California

Posted 18 April 2019 - 11:54 AM

ADM makes one also. Works well solid. A bit pricey and weights about 2lbs.

 

https://www.admacces...vetail-version/



#3 TOMDEY

TOMDEY

    Skylab

  • *****
  • Posts: 4230
  • Joined: 10 Feb 2014
  • Loc: Springwater, NY

Posted 18 April 2019 - 12:19 PM

The ADM thing looks more traditional and sturdy. The Astromania one also looks intriguing. It is rather comical to see those two opposing micrometer barrels being used to adjust and clamp the load! Nothing inherently wrong with that, but reminds me of the mechanical engineers referring to a precision micrometer gauge as a "Calibrated C-Clamp" because of the way inexperienced engineers would abuse such precision tools.

 

You can mimic any of those approaches, on the cheap... just using plates, screws, etc. Would depend on how much your time is worth to you. Could easily spend a couple of days concocting something that might or might not work well. And, sometimes when done... have spent just as much $$$ anyway. I'm not saying to avoid that... I do it all the time... Usually because I need something that is just not available. Like this 2-axis adjuster mount that I built to hold a heavy 8-inch finder scope! >>>   Tom

Attached Thumbnails

  • 38 Toms 2-axis mount for 8-inch finder.jpg
  • 39 70 Finder Scopes usnig Vixen hardware.jpg

  • barsuda likes this

#4 JS999R

JS999R

    Mariner 2

  • *****
  • Posts: 224
  • Joined: 07 Dec 2011

Posted 18 April 2019 - 01:22 PM

Above all else, my objective would be to have any device to be close to flexure free.  The common finder rings with delrin tipped screws is not the answer according to Roland C of Astro Physics.  Nothing about flexure is addressed that I could see in the Astromania device. 

 

If the manufacturer could confidently state their device is much better than the finder rings in terms of controlling flexure, then I would certainly be interested. Besides that, it's a cool hi tech looking kit. 


Edited by JS999R, 18 April 2019 - 01:25 PM.


#5 DuncanM

DuncanM

    Mercury-Atlas

  • -----
  • Posts: 2592
  • Joined: 03 Nov 2009
  • Loc: Arizona Sky Village or the rain forest

Posted 18 April 2019 - 03:05 PM

Something like this should work:

 

https://www.telescop...pter/p/7033.uts


  • barsuda likes this

#6 scadvice

scadvice

    Apollo

  • *****
  • Vendors
  • Posts: 1226
  • Joined: 20 Feb 2018
  • Loc: Lodi, California

Posted 18 April 2019 - 03:07 PM

Delrin tip screws are fine if the design is proper. i.e. larger screw and surface area that is curved to match the tube. The compressive strength of delrin is quite high for plastics at 5000psi. Though having said this, I'm not a fan of the rings being used for a guider. A finder is fine but not on a guider if it can be avoided.

 

However,  I'm testing this setup below and the Delrin tipped screws used here are working fine even though they are a bit of a contradiction to my first paragraph statement. 

 

The WO red Vixen DT will be going away as will the scope mounting bracket and replaced with two solid mounting rings on their own Vixen type mounting plate. 

Attached Thumbnails

  • pp22.jpg

Edited by scadvice, 18 April 2019 - 03:25 PM.

  • barsuda likes this

#7 SteveInNZ

SteveInNZ

    Viking 1

  • *****
  • Posts: 667
  • Joined: 07 Oct 2007
  • Loc: Auckland, New Zealand

Posted 18 April 2019 - 05:27 PM

I have a Vixen XY guide mount. Very solid but perhaps not the economical solution you are looking for.

The cheapest option is probably to use a side-by-side setup and shim one of the scopes to line them up.

 

Steve.


  • barsuda likes this

#8 Chuckwagon

Chuckwagon

    Viking 1

  • *****
  • Posts: 725
  • Joined: 23 Jan 2008
  • Loc: Orem, Utah, USA

Posted 18 April 2019 - 05:53 PM

I have a Vixen XY guide mount. Very solid but perhaps not the economical solution you are looking for.

The cheapest option is probably to use a side-by-side setup and shim one of the scopes to line them up.

 

Steve.

I like the side-by-side option with shims to adjust the aim.  It may seem a little more daunting for balancing, but in reality it gives you greater flexibility in dealing with odd shapes and mass centers and still allows you to get perfect balance.  Plus it keeps the overall center of mass closer to the mount, which helps keep the CW closer or lighter.  And, when you do decide to get a different scope, it's an easy swap.  That'd be my choice.  :)



#9 alphatripleplus

alphatripleplus

    ISS

  • *****
  • Moderators
  • Posts: 73147
  • Joined: 09 Mar 2012
  • Loc: New Jersey

Posted 18 April 2019 - 05:54 PM

Moving this to Equipment for a better fit.



#10 Don W

Don W

    demi-god

  • *****
  • Administrators
  • Posts: 22996
  • Joined: 19 May 2003
  • Loc: Wisconsin, USA

Posted 18 April 2019 - 06:57 PM

These are getting pretty scarce but I have two Celestron tangent mounts from the 80s. One came with a C5 guidescope and the other can be adapted to other types of scopes/rings. They have 2 axis adjustments, up/down and left/right.

 

IMG_0883.JPG

 

guide mount.jpg


  • barsuda likes this

#11 barsuda

barsuda

    Lift Off

  • *****
  • topic starter
  • Posts: 18
  • Joined: 27 Aug 2018

Posted 19 April 2019 - 03:19 PM

The ADM thing looks more traditional and sturdy. The Astromania one also looks intriguing. It is rather comical to see those two opposing micrometer barrels being used to adjust and clamp the load! Nothing inherently wrong with that, but reminds me of the mechanical engineers referring to a precision micrometer gauge as a "Calibrated C-Clamp" because of the way inexperienced engineers would abuse such precision tools.

 

You can mimic any of those approaches, on the cheap... just using plates, screws, etc. Would depend on how much your time is worth to you. Could easily spend a couple of days concocting something that might or might not work well. And, sometimes when done... have spent just as much $$$ anyway. I'm not saying to avoid that... I do it all the time... Usually because I need something that is just not available. Like this 2-axis adjuster mount that I built to hold a heavy 8-inch finder scope! >>>   Tom

I agree with you that the ADM finder rings alternative is likely the most sturdy. Unfortunately it is also the most expensive frown.gif I had the same concern as you about the Astromania offering (and several other like it) that the micrometer adjustment is also being used to stabilize the load. This would seem like a recipe for flex when changing eyepieces, changes in altitude etc. Too bad these adapters are so expensive as it makes it more difficult to decide to just "give em a try". I will ponder a little more before spending the $.

 

I liked your two axis adjuster for the 8" finder. Any design I have come up with has been lacking when it came to the rotational component (altitude on yours). I was wondering what the details of the altitude adjustment (the round white column) are. I am curious about the origins and specifics of that part. 

 

Thanks for the posting.

Attached Thumbnails

  • post-226662-0-79110300-1555607637.jpg


#12 TOMDEY

TOMDEY

    Skylab

  • *****
  • Posts: 4230
  • Joined: 10 Feb 2014
  • Loc: Springwater, NY

Posted 19 April 2019 - 09:21 PM

I agree with you that the ADM finder rings alternative is likely the most sturdy. Unfortunately it is also the most expensive frown.gif I had the same concern as you about the Astromania offering (and several other like it) that the micrometer adjustment is also being used to stabilize the load. This would seem like a recipe for flex when changing eyepieces, changes in altitude etc. Too bad these adapters are so expensive as it makes it more difficult to decide to just "give em a try". I will ponder a little more before spending the $.

 

I liked your two axis adjuster for the 8" finder. Any design I have come up with has been lacking when it came to the rotational component (altitude on yours). I was wondering what the details of the altitude adjustment (the round white column) are. I am curious about the origins and specifics of that part. 

 

Thanks for the posting.

Yes, here's a couple more pictures... pretty self-explanatory. My neighbor turned that solid aluminum stem on his lathe to fit the repurposed (white) aluminum railing flange that I bought on-line. The design and build took me a couple of days of screwing around. Well, it's sturdy, looks good, and works fine. On the other hand... that Astromania thing looks elegant and might just work even better. They say it will support 15 Kg (33 pounds)... Hmmm... Note that it also has four locking screws, two on each axis. So you are not relying on those micrometers and thumb elevator for anything other than adjustment. That should be sturdy and stable. I'm actually tempted! Mine has no fine-adjust. I might actually get that red thing and fiddle around with it!    Tom

Attached Thumbnails

  • 54 Vixen Mount 1 60.jpg
  • 55 Vixen Mount 2 60.jpg


#13 TOMDEY

TOMDEY

    Skylab

  • *****
  • Posts: 4230
  • Joined: 10 Feb 2014
  • Loc: Springwater, NY

Posted 19 April 2019 - 09:22 PM

Couple more pics...    Tom

Attached Thumbnails

  • 52 Vixen Mount 3 60.jpg
  • 53 Vixen Mount 4 60.jpg


#14 barsuda

barsuda

    Lift Off

  • *****
  • topic starter
  • Posts: 18
  • Joined: 27 Aug 2018

Posted 20 April 2019 - 09:55 AM

Something like this should work:

 

https://www.telescop...pter/p/7033.uts

Coincidentally I actually have one of these Orion slow motion adapters that I used to mount my binoculars for a time before I upgraded to a fluid head. And coincidentally I had set up the Orion adapter as a alignable shoe (see photos below from when I prototyped the rig). 

 

The result was mixed. The good part was the Orion's slow motion controls worked really well for aligning the scope. Because I am mounting sidesaddle there was a lot of rotational torque on the Orion which I solved by drilling and tapping the Orion both ends for a second mount bolt. The bad part, the Orion is 4" tall, which introduces a fairly long moment arm which results in significant flex when changing eyepieces or focusing. With a light touch, flex and vibration are tolerable but far from ideal. As configured I believe this setup would be adequate for a scope up to about 3 lbs but is overloaded at the 5 lbs of the ST80. It kinda works for visual or as a finder but would be inadequate as a guider mount. 

 

Bottom line is that it worked well enough that I am currently using the Orion adapter as a alignable shoe while I figure out a more robust solution.  (I am expecting a letter any day now from Orion demanding I cease and desist my off-label usage of their product) smile.gif  

 

Guide Mount 3 - Apr 2019_opt.jpg

Guide Mount 2 - Apr 2019_opt.jpg




CNers have asked about a donation box for Cloudy Nights over the years, so here you go. Donation is not required by any means, so please enjoy your stay.


Recent Topics






Cloudy Nights LLC
Cloudy Nights Sponsor: Astronomics