Side-by-side dual scope mopunting on EQ6

[bojan]

In order to avoid too much re-arranging when I want to use different scopes on my EQ6, I was thinking about parallel mounting of all 3 of them (C11, Rubinar 10/1000, Canon 400 f/2.8).
To reduce mount load, I want to replace some counterweights with scopes.. Canon is 5.5kg, Rubinar 2.7.. so some more weight should be added at the shaft or Rubinar should be mounted further away from shaft for proper balance.
Did anybody tried something like that?

Of course, collision with pier could be an issue, but I am trying to be careful with that anyway, my mount is not fully automated.

[bojan]

More detailed design drawing is attached.
I decided to machine new nut for counterweight shaft, and use modified ADM dovetail bar (leftover, my C11 came with two of them), fixed to the RA axle. Also I intend to use surplus EQ6 saddle (I am using ADM-style saddle for C11) for Canon 400mm and Bintel vixen dovetail adapter for lighter Rubinar 10/1000 (or whatever).
I hope for the best :)


Cheaper alternative is to use 2 aluminium 10 or 12 mm square bars (https://www.aluminiumtc.com.au/store/product/view/12-x-12-640/?pid=640) instead of Bintel clamp and fix them with screws on the ADM plate.
To achieve scope parallelism, only one dovetail clamp needs to be rotatable around mounting screw.

[iborg]

Hi Bojun


Looks good and I am glad something is keeping you off the streets!


Have fun.


Philip

[JA]

Hi Bojan,

I think it's a great way to more fully utilize the drive capabilities of the mount rather than waste it driving too many counterweights as well potentially offering the benefit of increasing the effective payload and allowing you to use your EQ6 and not have to go for a larger weight class mount.

Of course, as you already mentioned, this is all at the expense of much greater care being required when slewing, during go-to or positioning the system for fear of a collision. Also using a pier, as you are doing, gives you more clearance than a tripod.

Just a thought: If you only wanted to add say one extra optic, and wanted an easy/quick&dirty mod you could consider mounting it to a counterweight placed at the end of the counterweight shaft and thereby have an intrinsic angular adjustment built in and also retain the ability to shift the counterweight/ota assembly for balance by moving the entire counterweight shaft in/out. Your way fashioning a new nut etc, is of course more rigid, but quick and dirty may be of some use too.


Best
JA

[bojan]

Hi JA,
Thanks for the comments :-)
Yes, adding more instruments by minimal increase in counterweight was my intention for this project.
Also using available h/w that would otherwise just collect dust (I am not very good regarding selling anything.. either I give it away or keep it.. especially because some of those bits and pieces were given to me by some members of this forum).

There is a way to add more gadgets, my dovetail bars are quite long (~300 mm), so I can use those places without disrupting the balance too much.
For example, the guider scope (Samyang 500mm f6.3 probably) will be on the C11 side , below corrector plate, attached to ADM bar.


Another improvement will be to run cables (power, USB) through RA shaft, to avoid the mess...

[bojan]

I found in my stock a wide dovetail plate (donated some time ago by Avandonk), it looks like the ideal solution for my case.
There is a need for some machining (which will NOT compromise the original functionality (not really relevant at this time), mainly hole drilling and thread tapping..).

This is what it will look like...

[By.Jove]

I suspect you're going to have issues with them hitting tripod legs...

[Ryderscope]

It appears from your drawings and text that there is one guide camera/scope mounted on the top plate and that this will be providing the guiding function for the two cameras mounted on the counter weight shaft. One thing to consider is the possibility of differential flexure between the guide camera and the imaging cameras in this configuration. You will very likely find that this design may not deliver quality data even with the relatively short focal lengths. I suspect very strongly that you will find trailed stars on longer exposures when imaging with the cameras on the counter weight shaft.

[bojan]

Jove, Rodney,

Thank you for the comments.

Yes, I am aware of all those potential issues.. but I have to try it.
Guiding won't be the problem (I think), guiding camera will be mounted where needed (and I plan for OAG or ONAG anyway).

My problem is, C11 is very heavy (for me), and I want to avoid un-necessary stress on my back, if possible.

[Ryderscope]

All good. I get the bit about handling heavy OTAs given my dodgy lower back as well. It is good to have a stable configuration that doesn't need too much fiddling.

[bojan]

Moving on, slowly...
I still need to machine the provisions for attachment on the counterweight side (ø20mm hole in the puck), at this moment the assembly can be used in traditional way.