Concern about load distribution on my system. (FMA180)

[LaurenceT]

I've been breaking my head for months about how to use my FMA180 on a mount using a guidescope/camera and my Asiair. The only method that "looks" remotely feasible is the one in my photos. The problem is of course the added weight to the camera. The total weight with both the guidescope/camera and the Asiair is 915g (32oz). If I decided not to guide and just use short exposures with the Asiair by itself the total weight is 622g (22oz). The Asi122mm mini camera is not in the photos as it's currently on my 50ED.

I haven't yet used this in anger so I can't say anything about tilt but I'm concerned about the strain on the whole imaging train.

Be grateful for any comments.

Edited December 12, 2023 by LaurenceT

[Chris-h]

I bought one of THESE from TS before Brexit, but I'm sure someone sells them over here as well. Lots of holes, which makes balancing things sooo much easier!

[Elp]

You can do that or use two dovetails bolted together in a cross formation, or use camera cheese plates which is how I started with my dual lens rig.

[Elp]

If the dovetail is long enough I have also bolted the guidescope underneath the dovetail at the front but you have to check whether it will foul with the mount head when the declination rotates.

[900SL]

That guidescope is likely to cause issues with flexure when guiding. Don't do it. 

You are also quite high, with the FMA180 mounted up and the ASI and Guidescope even higher. This increases both the moment, the inertia and the counterweight. Rethink it. 

A quick google image search should throw up some ideas

[LaurenceT]

3 hours ago, 900SL said:

That guidescope is likely to cause issues with flexure when guiding. Don't do it. 

You are also quite high, with the FMA180 mounted up and the ASI and Guidescope even higher. This increases both the moment, the inertia and the counterweight. Rethink it. 

A quick google image search should throw up some ideas

@Chris-h I'll certainly check that out.

@Elp I'm sure I've got a similar plate from my photography days, I'll have a search.

 

@900SLYou're quite right, the whole thing looks absurd, it would never fly! I'm abandoning the ZWO holder ring and I've found a way to mount the Asiair on top of the dovetail under the front of the scope. I'll have to be content with taking shorter unguided exposures which shouldn't be a problem with this widefield scope. If I was desperate to guide there is a way to mount a guidescope with this. I tried it the other day with this bar, it was OK, but clunky and a bit of a faff balancing it:

 

 

[Elp]

That's why the cross dovetail or losmandy method works, you can fix the equipment at the right places so you can get good declination balance. For my current dual rig I've fixed various mini vixen saddles at various positions so I can move them about depending on what lenses or cameras im using. Before I used to physically chop and change the hardware which was a hassle.

[LaurenceT]

I've found what I think is the best solution. It's a 3D printed design and it came all the way from Illinois! Found a young chap on Facebook who makes a number of items related to astro, he possesses a Samyang 135 and the US equivalent of the Askar FMA180 so he is able to get the precise dimensions and has made products for both scopes/lenses. He goes by the name of Chris and his company is called Thinkable Creations, to order you have to go onto Etsy of all places. There appear to be two areas, one devoted to astro and the other to random bits. It looks a bit unusual and it wasn't cheap but it now means I can mount the Askar together with a guidescope and Asiair in a normal fashion without risking everything revolving like a windmill eventually!

[Elp]

Do you know what filament was used for the 3D prints? Unless it was ABS, PETG or nylon I would not trust to load such costly equipment onto it, and certainly do not leave it anywhere near sunlight or heat sources.

Edited December 27, 2023 by Elp

[LaurenceT]

Made with PETG

[Adam J]

On 12/12/2023 at 11:31, LaurenceT said:

I've been breaking my head for months about how to use my FMA180 on a mount using a guidescope/camera and my Asiair. The only method that "looks" remotely feasible is the one in my photos. The problem is of course the added weight to the camera. The total weight with both the guidescope/camera and the Asiair is 915g (32oz). If I decided not to guide and just use short exposures with the Asiair by itself the total weight is 622g (22oz). The Asi122mm mini camera is not in the photos as it's currently on my 50ED.

I haven't yet used this in anger so I can't say anything about tilt but I'm concerned about the strain on the whole imaging train.

Be grateful for any comments.

I side by side mount mine with the guide scope.

So one of these:

https://www.firstlightoptics.com/dovetails-saddles-clamps/astro-essentials-mini-vixen-style-dovetail-clamp.html

and two of these 18cm dovtails:

https://www.firstlightoptics.com/dovetails-saddles-clamps/astro-essentials-dovetail-bars.html

The you can just mount side by side and balance in both directions. 

easy.

There is a second one here too that i am using to clamp it to the back of the esprit 100, ignore that one, its effectively your mounts vixen clamp equivalent. 

Adam

Edited December 27, 2023 by Adam J

[ollypenrice]

I try not to over think mounting issues. I'd be looking simply at bolting a flat alloy plate to the top of  the Vixen rail and drilling a few holes in it so all the components could be bolted side by side onto this plate. Nothing long or spindly and no 3D printing within a five mile radius.

Olly

[AKB]

On 27/12/2023 at 17:00, Adam J said:

I side by side mount mine with the guide scope.

…and number ALL of your equipment assets??!

Impressive.  You have a spreadsheet or database, I take it?

[Adam J]

18 hours ago, AKB said:

…and number ALL of your equipment assets??!

Impressive.  You have a spreadsheet or database, I take it?

Just the mobile imaging rig. So I don't get to the top of a mountain and find I am missing a USB cable.