Nice to see some innovation from someone with a CNC machine.
Now if only they'd made a provision for encoders...
It's sold through AliExpress.
Encoders
Then it would not be simplicity
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Re belts slipping, no way.. and they last ages in application like this, being not loaded (of course, balance is essential here but the applies to worm gear).
I don't know what you mean not loaded any pulley system is loaded, place a scope on the mount driven by turning the knob and you are moving a load via a belt that has to be kept tension-ed ?
By not loaded I really meant not overloaded...
Of course the belts need to be under certain tension, but for this application ~1N is more than enough.
And the ones pictured can be loaded with more than 100N I am sure
The load imposed by moving the telescope (provided it is balanced) with reasonable acceleration should not be higher than 0.1Nm, so this translates to ~10N.
They have some interesting gear on the Hercules website.
How about Four 80mm APO scopes for LRGB imaging (filters included with the price, cameras not included).
By not loaded I really meant not overloaded...
Of course the belts need to be under certain tension, but for this application ~1N is more than enough.
And the ones pictured can be loaded with more than 100N I am sure
The load imposed by moving the telescope (provided it is balanced) with reasonable acceleration should not be higher than 0.1Nm, so this translates to ~10N.
Forgot to mention - exactly the same principle (timing belt on friction wheel) I used ~13 yo for motorized focuser (I still use it for visual), see attachment.
Tension is controlled by means of excentric drum (motor is inside it).
Forgot to mention - exactly the same principle (timing belt on friction wheel) I used ~13 yo for motorized focuser (I still use it for visual), see attachment.
Tension is controlled by means of excentric drum (motor is inside it).
yes but that has teeth the other is a plain surface
Still leaves one shiny surface
Last edited by Ukastronomer; 05-03-2019 at 07:14 PM.
yes but that has teeth the other is a plain surface
If you look at the photo carefully, you will see the flat groove on the focus knob (so belt can't fall off) - because I wanted to be able to use it manually by lowering tension (and friction)... Teeth are on the small pinion.
I belive they were driven by the same idea when designing the mount we are disscussing.
The only problem I see with that mount is relatively low transmission rate, so the positioning will be quite cuarse.
But probabbly OK for shorter FL and lower magnifications....
Well, it arrived... interesting. A a visual travel scope this would very easily take a 100mm refractor and certainly a step up from what i had before. It would also take my MN56 mak newtonian well enough, though that will need a decent tripod.
Each axis has a roller thrust race, approx 90mm diameter. Massive overkill, mechanically. The central stud also has a thrust race and a hefty knob to tighten the pressure, resulting in modest drag (friction). Probably feasible to add encoders with some custom parts, if you wanted to.
The belt drive is effective. No noticeable backlash. The pinion has a flat and a setscrew to lock it on the shaft with the knob; it would be rather easy to undo this and make a DIY shaft driven by a small motor (if you wanted to motorise).
It requires 8mm bolts to attach the dovetail base (trip to Bunnings) and there is a 10mm threaded hole for a counterweight bar, so I'm off to find one that fits (mine is 12mm).
Central hole in the base appears to be ¼" x 20, though there are 2 x 8mm holes at 35mm apart and 2 x 8mm at 70mm apart, if you want to bolt it onto a substantial baseplate of some sort.
Only downside is that the edges of the roller thrust races are a little exposed and dust will get in. A felt ring would fix that and keep the dust out (simple DIY job).
Well, it arrived... interesting. A a visual travel scope this would very easily take a 100mm refractor and certainly a step up from what i had before. It would also take my MN56 mak newtonian well enough, though that will need a decent tripod.
Each axis has a roller thrust race, approx 90mm diameter. Massive overkill, mechanically. The central stud also has a thrust race and a hefty knob to tighten the pressure, resulting in modest drag (friction). Probably feasible to add encoders with some custom parts, if you wanted to.
The belt drive is effective. No noticeable backlash. The pinion has a flat and a setscrew to lock it on the shaft with the knob; it would be rather easy to undo this and make a DIY shaft driven by a small motor (if you wanted to motorise).
It requires 8mm bolts to attach the dovetail base (trip to Bunnings) and there is a 10mm threaded hole for a counterweight bar, so I'm off to find one that fits (mine is 12mm).
Central hole in the base appears to be ¼" x 20, though there are 2 x 8mm holes at 35mm apart and 2 x 8mm at 70mm apart, if you want to bolt it onto a substantial baseplate of some sort.
Only downside is that the edges of the roller thrust races are a little exposed and dust will get in. A felt ring would fix that and keep the dust out (simple DIY job).
So...happiness? I'm curious as to what else you have to add to get it working. How do you attach it to the scope? How do you attach it to a tripod? Given goto mounts are available for $600, I wonder if it's a real alternative, or more of a novelty?
OK Depending on how you source these it may not be cheaper than just buying a complete rig, but if you have some of the bits it will make a nice mount. You need to add...
3. 2 x M8 cap screws to bolt above onto the head.
4. Counterweight bar and counterweight. The bar must have a 3/8" thread to fit, and the weight needed is 1-2kg.
Alternatively a trip to a machine shop to have the hole drilled and threaded for M12 - which I may have to do - as I have a spare bar (and weight) with M12 thread. I've already contacted Hercules and suggested they make the hole M10 or M12 n future to match the commercially available bars.
Nice light weight travel mount you've picked up there!
Would it need the counterweight? or would just a sturdy tripod surfice as with a dm4.
Looks like it would be buttery smooth though.
You could indeed use it without a counterweight provided its bolted onto something solid !
Yes it is smooth. The central knobs allow a variable loading to be applied so its adjustable from very free to having useful drag.
OK Depending on how you source these it may not be cheaper than just buying a complete rig, but if you have some of the bits it will make a nice mount. You need to add...
3. 2 x M8 cap screws to bolt above onto the head.
4. Counterweight bar and counterweight. The bar must have a 3/8" thread to fit, and the weight needed is 1-2kg.
Alternatively a trip to a machine shop to have the hole drilled and threaded for M12 - which I may have to do - as I have a spare bar (and weight) with M12 thread. I've already contacted Hercules and suggested they make the hole M10 or M12 n future to match the commercially available bars.
BTW the belt drives give a reduction of 8:1.
Is the mount interface the dovetail? or is that for the scope? I only know Film TV tripods that use a bowl system. I'm not sure what a standalone astro tripod uses for interfacing to the head.
Low cost, but not "cheap" 
