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Gimbal with astroscope (1 Viewer)

cango

Well-known member
Have been looking at gimbals, and have one question to those of you that use one with astroscope.

How is balance affected while manual focusing? As I understand it, the gimbal functions with achieved balance. But the way an astroscope is focused - back and forth on it's rail - surely it must affect balance. But perhaps not as much as affecting the balance (too much)?

What's your experience?

Thanks.
 
I used a Manfrotto 393 which in my opinion, is the best bang for buck Gimbal out there.

You are right that the balance is not upset too much when changing focus / racking in and out on the scope. But you can eliminate any tipping back and forward of the scope by setting the tension on the swing of the Gimbal to a bit stiffer. Thats what i did

When you're setting the balance point, have your scope racked in / out about halfway through its travel with your camera attached. Dont balance the scope with the focuser racked right in or right out.

Mine worked fine after that. No problem with balance when changing the focus
 
"When you're setting the balance point, have your scope racked in / out about halfway through its travel with your camera attached."
Yes, that's what I thought would be the most logical to do.
Don't have the bucks to buy one, but thought maybe doing one myself. The manfrotto "style" should be doable with the means I have I think. (I'm into woodworking, not metal)
 
I think any decent metal worker with some tools and some patience could make a decent gimbal. Give it a go Cango !

Not me though, i'd just buy one :)
 
Very well answered Musoman. I recommend balancing the scope at the usual shooting position.

Cango, I got mine DIY for less than US$10. I only need to pay for 4 sets of new Ball Bearing. Used various sizes of G I Pipe for the bearing seat and curved pipe. Even the mounting plate are recycled from discarded aluminium blocks.... All in all, weigh in at about 800g, much lighter than Gimbal. I attached two pic taken before it was completed so as to see the bearing and plates. Tried loading it up to 20kg yet not a shake.

Mt centre of gravity of the scope is actually almost an inch below the horizontal bearings to allow the scope to maintain better horizontal position regardless the position of the focuser tube. Still feel very easy to pitch the scope with the lowered centre of gravity. And focusing are much much better than other tripod head.
 

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alphan: Nice!

I have - in theory - always discarded mounting a telescope the way you have. Does it work practically - to have the focusing wheels shifted on the side like that? Always felt it must be awkward, but apparently it works.

Begun with my idea today. Thermoforming some Corian, (seen it done, but never really done it myself). The mounting plate did not fit (well, the screw on the side) so I must put some distance underneath. have to fix how to mount it onto the tripod.
I have no ballbearings, hope to do without.
 

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Manfrotto sell the big sliding plate off the 393 gimbal without having to buy the Gimbal itself, if you guys are interested
 
Very nice work Cango!
I really think you should use bearings though. I have a manfrotto 393 too, but dislike it a lot as it is, I'm modifying it right now to add some bearings, as it is it's just not stable enough. My Benro KB3 is far more stable, specially when adding TCs. The main problem I find on the 393 is the lack of bearings on the main pivot.

Care to explain how you built the arms? Really curious about it.
 
Very nice work Cango!
I really think you should use bearings though. I have a manfrotto 393 too, but dislike it a lot as it is, I'm modifying it right now to add some bearings, as it is it's just not stable enough. My Benro KB3 is far more stable, specially when adding TCs. The main problem I find on the 393 is the lack of bearings on the main pivot.

Care to explain how you built the arms? Really curious about it.

Thanks.

The thing with bearings, is that I don't know how or what kind. But it's not only the bearings - it's how to fasten it and so forth.(as I said, I'm not into metal...)

I build the arms out of a piece of 12mm thick Corian (http://corian.co.uk/Corian/en_GB/index.html) at work I have a CNC router, and first I machined a flat piece - 470mm x 50 mm . Then I made a sort of mould of 35mm MDF with rounded corners. then I heated the corian up in our veener press. when the corian was flexible (heated, it behaves like rubber and you can curve it and stuff) then I put it on the mould and put press from 2 sides, and waited til it was cold again and regain it's stiffness/hardness.

Perhaps it's not the best material to work with, but it's what I've got. With all the snow we are having now, I wont have to camo it until spring, haha.
 
Interesting, I had never heard of corian before. Looks a great material for many diy projects if you have a way to work with it and get it.

I wonder how rigid is it, doesn't it flex after cooling?

The bearings are not dificult, some stores have bushings and fittings to make it work without a lot of work. And if you want the easy way, at least for the main pivot point you could adapt a bicicle aheadset ;). I though about that on my 393, but I'm going with bearings alone and some machining.
 
it is quite rigid in itself, but the U shape of mine does flex some if I grab it by the "horn" and pull it outwards. But I bet I could flex one in metal as well.

We use Corian (and materials like it, LG Hi-Macs, etc) for kitchen countertops/sinks and other interior details/designs. Therefore we always have some bits and pieces left. Otherwise it would be too expensive to do DIY-stuff.

The bicycle-idea, I liked. will look into it. Have and old bike I could use for parts.
 
I have the 393, which I like very much - had thought about making it lighter by drilling large holes in most of the framewwork - I wonder if it will work without compromising strength/usability
 
This idea must have been floating around in the air recently, as just a week or so ago I started on building a gimbal, in my case made out of wood. Not nearly as professional-looking as Alphan's or as elegant as Cango's - I am very impressed with both of your designs. Mine is not finished yet, as I am waiting on a quick-release plate, but it seems very rigid. Construction material is 3/4 ply, and the bearings are 1/4" bolts running in metal sleeves. (It's going to mount on a pan head that I have, so hopefully that will take care of that bearing).
 

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Cango, very professionally done. Looks like factory mass produced.

Because of the weight of the scope, extension tube, TC and camera, I am reluctant to built something based on the Manfrotto 393 series. I actually did built a prototype out of discarded aluminium plates but it feels too fragile. So the next easier model would be the Gimbal Black Widow Lightweight but with everything in heavy duty. The other Gimbal would create another angles base thus additional weight and more room for flex and vibration. Focusing is just a breeze, being close to my pitching lock screw. I can reach for each other without having to search for them and each other became the palm rest for the other.

The disadvantage of the Manfrotto are :
1) (as mentioned by Fernando) no bearings thus making the pitching a little inconsistence.
2) when locking the pitching, you got to lock both screws instead of one.
3) with both pitch and swing locked, you still get some flexing (thornlv-do not drill any holes in your legs, or the flexing will deteriorate).

When shooting with TC, I usually lock the pitch screw but exert some downward pressure on the camera or extension tube to reduce scope pitching vibration.

Finding the right bearings aren't difficult. I just need to know the common pipe sizes and thickness, the common bolts (to use as bearing shaft) and head for the bearings dealers. In fact they are very well versed with those sizes. I just cut a short length of the pipe and use the internal diameter as bearing seats and insert the crew through and tighten. Just bend another smaller pipe and weld them together (with bearings removed first) and assemble. I use double bearing on both horizontal and vertical axis.

Agea, very innovative... Never thought about about using plywood for it. I did once thought about using truck pistons which are made of aluminium and when cut across, would form an U shape. But the inconsistency with the absence of bearing make me think something else. The combines weight of the pan head and your DIY 393 would be quite high.

Never heard of this Corian before. Now I got another material to watch out for..
 
This idea must have been floating around in the air recently, as just a week or so ago I started on building a gimbal, in my case made out of wood. Not nearly as professional-looking as Alphan's or as elegant as Cango's - I am very impressed with both of your designs. Mine is not finished yet, as I am waiting on a quick-release plate, but it seems very rigid. Construction material is 3/4 ply, and the bearings are 1/4" bolts running in metal sleeves. (It's going to mount on a pan head that I have, so hopefully that will take care of that bearing).

very nice. see that you thought of rising the plate up a bit (which I missed hehe). Some black or camo paint/tape and you're done!
 
The disadvantage of the Manfrotto are :
1) (as mentioned by Fernando) no bearings thus making the pitching a little inconsistence.
2) when locking the pitching, you got to lock both screws instead of one.

Yes, the need to lock both screws is not ideal. we'll see how it turns out. That's the fun in DIY. You work with what you've got, and spend only time - which indeed has it's value, but as long it's fun, it's time well spent.
 
Alphan, would never mess about with my legs. I need them for walking ;) Also have a Giottos VH 6011 pan/tilt head which is about a third of the weight of my 393, only problem I have with it is when tilting from down to up, there is some play - not noticable on close shots but the further the shot, the more play is noticed. Will probably look into how to stop that or minimise it at least.
 
Alphan, would never mess about with my legs. I need them for walking ;) Also have a Giottos VH 6011 pan/tilt head which is about a third of the weight of my 393, only problem I have with it is when tilting from down to up, there is some play - not noticable on close shots but the further the shot, the more play is noticed. Will probably look into how to stop that or minimise it at least.

I don't mean your two legs LOL... I improve my pitching control by pulling my camera strap down against the tripod leg, effectively creating a triangle support.
 
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