Perfect Balance

[markse68]

No point having a nice mount with smooth action if you have to put the brakes on to counter it's balance shift as you go from horizon to zenith- this has been bugging me for a while now so I cobbled together a balancing device for my rig.

The trouble is it's easy to get horizontal balance just shifting the scope along its dovetail rail but heavy eyepieces and finders that stick out from one side put it really out of balance as you tilt up. My current finder assembly alone weighs ~1.8kg and its mounted to the top of the OTA. So I find myself having to tighten the brake or shift the balance depending what altitude I'm aiming at which is quite an annoyance!

I started with this crude looking but compact weight I made from 1.2kg of roofing lead sheet laminated together with double sided tape and formed to fit the tube, and spaced off the tube by layers of foam. It worked fine with my old Skywatcher RACI but that was a lot lighter. I tried spacing it some more with the additional white foam but it never worked perfectly and I realised it really needed to be adjustable as changing eyepieces threw it out and again the brake was needed.

I've been picking up useful looking bits over the past few months- a nice small 850g counterbalance weight in SS and a second hand ADM MDS accessory clamp. A length of aluminium bar keeps the overall weight down and allows adjustment of the weight in or out from the OTA.

I looked for an MDS accessory rail in the classifieds for a while but I don't think I've ever seen one come up second hand and they are way too expensive new so I drew this bracket thing up and had it printed in nylon. I didn't really want to drill any holes so it's mounted with a webbing strap- I still have to sort that out as I don't want a bulky ratchet strap and the luggage strap I'm using here isn't really very secure. Rubber feet pads are glued into recesses to stop it sliding around on the OTA. I'm fairly confident that the nylon print is plenty strong enough and should survive repeated removal and refitting of the ADM clamp- it will be permanently mounted to the tube.

I can now achieve perfect balance in any position and that will make me a much happier observer  I'll just have to be careful not to keep knocking the weight bar as it sticks out 20cm- hopefully that won't be equally or more annoying...

Mark

Edited January 26, 2023 by markse68
photos

[Captain Scarlet]

Your first picture … is that a “cost meter” telling you how much you’ve spent so far perfecting your deluxe Finder setup  ?

[CraigT82]

Nice idea with the sliding weight and bracket, and you’ve got the perfect wallpaper for checking eyepiece distortion! 

[josefk]

Thanks for posting. I’m always thinking about balance myself and all ideas go in the “stewpot”. 
 

I really like the set up you have there in general and I’ve admired it from afar on your thread about the tripod. It looks like a very simple and ergonomically nice to use “effective” set up. What I mean is it looks like it “gets out of the way” nicely.
 

Perfect. 

[markse68]

3 hours ago, CraigT82 said:

Nice idea with the sliding weight and bracket, and you’ve got the perfect wallpaper for checking eyepiece distortion! 

it is a distortion target as it happens Craig- not for eps though. I think if it were my wallpaper it’d drive me completely insane! 🤣

1 hour ago, josefk said:

I’m always thinking about balance myself and all ideas go in the “stewpot”.

Thanks Josef, Desert Sky Astro offer a neat counterbalance design I was thinking about using but this seemed a bit easier. Theirs uses a pivoting track for the weight to slide along allowing full balance to be maintained. Another idea for the stewpot

http://www.desertskyastro.com/QBS.html

I think having perfect balance is going to make a big difference in it completely “getting out of the way”  

8 hours ago, Captain Scarlet said:

Your first picture … is that a “cost meter” telling you how much you’ve spent so far perfecting your deluxe Finder setup  ?

Not quite Magnus 🤣 Obscene amount though, yes! But, it is really nice and I don’t regret it

Mark

Edited January 27, 2023 by markse68

[markse68]

It got its first use last night and it made a huge difference to usability- scope stays where i point it anywhere now with the brakes barely applying any friction so at high powers I can nudge the scope with ease to keep the target centred and with no annoying wobble or back-traction from having the brake applied too much. And i only kicked it once

Mark

[CraigT82]

3 hours ago, markse68 said:

It got its first use last night and it made a huge difference to usability- scope stays where i point it anywhere now with the brakes barely applying any friction so at high powers I can nudge the scope with ease to keep the target centred and with no annoying wobble or back-traction from having the brake applied too much. And i only kicked it once

Mark

Sounds like a dream! Nice work