Side-by-side saddle and dovetail suggestions


michael mccann
 

Hi
trying to mount C11 edge, 130mm and 80mm refractors on AP mount. The Astro-Physics mounts offer a variety of saddle and dovetail options. I’m looking for recommendations and links/images of how AP users resolved this. 


thanks

Mike


mjb87@...
 

Hi Mike,

I mounted a CFF300 (about 38lbs) and my 130mm GTX on an 1100 mount. With all accessories I was pushing the limits at about 105lbs. I mounted the DOVELM162 sideways on the mount and then used the 18" SBS plate in that. I then mounted the DOVELM162 on one side (for the CFF300) and for the refractor I used the shorter 10"  saddle in order to save weight.  The challenge was that I was fully loaded on the counterweight bar as you can see.



Given the diameter of the C11 I think you will need to use the full 18" SBS plate. Unfortunately, the combination of the two 16" saddles, the 18" SBS and the 10" saddle meant that I was carrying a lot of weight even before I got to the telescopes.

It did work but had disadvantages. For one, whichever telescope was on the "down" side barely cleared the walls. Also, the refractor was for imaging but the CFF was mainly visual and I'd often want to use each but at different targets.

Marty


Roland Christen
 


Also, the refractor was for imaging but the CFF was mainly visual and I'd often want to use each but at different targets.
You need another mount Smile

Rolando


-----Original Message-----
From: mjb87 via groups.io <mjb87@...>
To: main@ap-gto.groups.io
Sent: Mon, Apr 19, 2021 2:33 pm
Subject: Re: [ap-gto] Side-by-side saddle and dovetail suggestions

Hi Mike,

I mounted a CFF300 (about 38lbs) and my 130mm GTX on an 1100 mount. With all accessories I was pushing the limits at about 105lbs. I mounted the DOVELM162 sideways on the mount and then used the 18" SBS plate in that. I then mounted the DOVELM162 on one side (for the CFF300) and for the refractor I used the shorter 10"  saddle in order to save weight.  The challenge was that I was fully loaded on the counterweight bar as you can see.



Given the diameter of the C11 I think you will need to use the full 18" SBS plate. Unfortunately, the combination of the two 16" saddles, the 18" SBS and the 10" saddle meant that I was carrying a lot of weight even before I got to the telescopes.

It did work but had disadvantages. For one, whichever telescope was on the "down" side barely cleared the walls. Also, the refractor was for imaging but the CFF was mainly visual and I'd often want to use each but at different targets.

Marty

--
Roland Christen
Astro-Physics


mjb87@...
 
Edited

Indeed, Roland. That is excellent advice -- and why my brand new Mach2 was delivered in November!! (Remember the washer?)

I now have two mounts in operation. Much better solution for me (not to mention Astro-Physics.) The problem now is that I am spoiled by the absolute encoders, which is why I'm wait listed on them for the 1100.

Marty


michael mccann
 

Thanks 

I actually just figuring my new “used” mount . As they say spend your money on the mount. I did

. until I have enough for much larger “galaxy killer “, I’ll make my three scopes work.  I’ll look into that  saddle and plate configuration.  Right now I’m learning the software.  Which image capturing software are you using?


mjb87@...
 

Happy to help if I can. One thing to remember is that the mount balancing gets VERY complicated this way. There is an excellent write-up available from Astro-Physics that explains the various steps required.

BTW, if you have trouble securing the 18" SBS bar -- if Astro-Physics can't supply one in a reasonable time -- let me know. Mine is serving as a paperweight now.

Marty


Christopher Erickson
 

Balancing isn't that big of a deal. All it takes is a wooden pencil and a few pieces of blue painter's tape.

On the floor, use the pencil to find the center of gravity for each OTA setup. Have your cams, wheels, etc. in place and refractors set to approximate focus.

Mark the center of gravity on each OTA dovetail bar with bits of the painter's tape.

Mount the OTA's on your double/triple/quadruple, etc. tandem dovetail bar.

Center them in their dovetail brackets using the tape marks.

Put the entire assembly on the floor and find the center of gravity for the whole assembly with the pencil and mark it with the painter's tape.

Make sure your mount has enough counterweights on it.

Remove the OTA's.

Mount the tandem bar assembly on the mount.

Mount the OTA's on the tandem bar, starting with the biggest/heaviest.

Check EVERY KNOB THREE TIMES for tightness and security.

Go forth and slew.

P.S. ADM makes extra-long dovetail bars for building up double/triple/quadruple OTA assemblies.

P.P.S. I'll guarantee that none of the OTA's will point to exactly the same point in the sky. Use adjustable dovetail X-Y stages or focal plane X-Y stages for all but the biggest/heaviest OTA.

 



Roland's suggestion is best. Get another AP mount or three. LOL

"My advice is always free and worth every penny!"

-Christopher Erickson
Observatory Engineer
Summit Kinetics
Waikoloa, Hawaii


On Mon, Apr 19, 2021 at 12:53 PM mjb87 via groups.io <mjb87=verizon.net@groups.io> wrote:
Happy to help if I can. One thing to remember is that the mount balancing gets VERY complicated this way. There is an excellent write-up available from Astro-Physics that explains the various steps required.

BTW, if you have trouble securing the 18" SBS bar -- if Astro-Physics can't supply one in a reasonable time -- let me know. Mine is serving as a paperweight now.

Marty


michael mccann
 

Great instructions.

Marty I’ve sent an email, let me know if you haven’t received it.

I have some Losmandy saddles and had purchased the “Easy Balance Saddle” initially. I’ll try the SBS18”  with my existing saddles and see if that works. I’ll see if my 3D adjustable saddle can handle the 130mm.  I hadn’t thought to check if I could mount the Easy Balance saddle (162) horizontally. So I’ll try that

thanks


Worsel
 

Michael

If you cannot mount it sideways, ADM makes a unit that turns the bars 90 degrees.  It says Celestron, but it will fit any D-series dovetail
https://www.admaccessories.com/product/cgx-sbs-celestron-cgx-side-side-adapter/


Bryan