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Showing results for tags 'drive'.
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I am wondering if I have knackered the drive mechanism on my Sky-Watcher Skyliner 400p Flextube Synscan Go-To Dobsonian ? WHAT I DID: I did a quick collimation in daylight, and needing to swing the tube from vertical to horizontal I stupidly slackened the fixing hand nut on the wrong side, NOT slackening the drive release wheel on the correct side. Then I forcibly swung the scope from vertical to horizontal with the drive mechanism still engaged. WHAT HAPPENS NOW: The scope is fine optically of course, and both drive mechanisms (the 'compass' movement, and the vertical) appear to work fine, they sound normal and the scope moves at the normal speeds as far as I can tell. BUT, I cannot get it to align, for the GOTO system. When I do a two star alignment – I line up the first star, no problem. When the scope moves to suggested second star, it gets very close on the horizontal, but not close on the vertical – the axis which I forced the mechanism on. Previously, once aligned on the first star, the scope would move automatically to within a degree or so of the second, and only need minor readjustment. Of course I can move to align with the second star using the drives, but nevertheless, the alignment remains way off, 10 – 20 degrees off, which big errors particularly in the vertical axis, when I move to any other objects. I suspect I have damaged the drive / encoders. Does anyone know if a moderately practical amateur can repair these – or indeed replace them? Meantime I am learning how to find objects without the Go-To, which I find difficult – but rewarding. Thanks in anticipation for any advice. Jon
I have a Helios 200p (identical to the Skywatcher) mounted on an EQ3-2. I know it is overloaded but I find it OK for visual provided I give it a couple of seconds to settle down at high powers. I intend to motorise the mount using stepper motors & an Arduino. It will be tracking for visual only with a possible upgrade path to GoTo. Since I dont need fantastic precision and having read the relevant threads on this forum, I propose to drive the RA worm directly & the DEC with a simple belt drive. By avoiding a step-down gear set I will still be able to use the manual slo-mo controls without disconnecting the motors. I think that centering the target with the slo-mo's & then switching on the tracking will be nicer than using fast-forward & fast-reverse controls. But no step-down means no torque amplification. So how much torque do you need to drive an overloaded EQ3-2. I decided to do some quick & dirty tests. Apparatus 200p with 25mm Plossl & 9 X 50 Finder, payload about 9kg. EQ3-2 with 10kg of counterweights Improvised wooden pulley, effective radius 0.375 inch 2 X 1kg barbell weights piece of string Method For each axis ,with the clutches locked, a 1kg & then 2kg load was hung from the pulley & released. This was repeated for the opposite direction of rotation. Results DEC 1kg Torque 13.5 oz.inch Rotated smoothly at about 90 degree/minute DEC 2kg Torque 27 oz.inch Rotated quickly at about 300 degree/minute + RA 1kg Torque 13.5 oz.inch Did not rotate RA 2kg Torque 27 oz.inch Rotated smoothly at about 90 degree/minute Conclusion The required torque for RA would be on the limit for a (cheap, ungeared) NEMA 14 stepper but a NEMA 17 motor with a torque of 84 oz.inch should be up to it. So now all I have to do is order the bits & learn how to use an Arduino.
Hi guys, I have a chance to buy Lidl style Bresser refractor on this particular EQ mount. Does anybody here know exactly what mount it is? Do any of you any experience attaching a simple EQ2 motor drive to it? See below. It seems very sturdy compared to EQ2 so I'm tempted. I know there are probably not the same mounting holes on the Bresser EQ as there are on EQ2, but my hope is that the R/A gear and worm might be of similar size (and ratio) to EQ2, so that the speed of EQ2 motor drive rotation could accomodate it. If so, a little bit of DIYing might be enough. Any thoughts? Thank you very much.
I have a Celestron CPC 9.25 and a knocking sound began to come from the declination drive while tracking. The noise stops when slewing the drive in any speed but returns when tracking. The noise was intermittent and sometimes quite loud and so I looked online to see if this is a common problem and to find a cure. Several people reported the same fault but I couldn't find any information or images of the inner workings or how to fix it. I carried out the following three weeks ago and the knocking noise has stopped since then. To do this you will require the following items. 1 set of metric allen (hex) keys, 2 small O rings (see image) Small phillips screwdriver Lithium grease (optional) Begin by locating the hex screw on the declination clutch knob (see image) Undo this screw and turn the knob anticlockwise until it comes off the spindle. Locate the six hex bolts on the inside of the fork arm and remove them. The bottom and middle screws are the same but the top pair are longer but both different lengths. You may have to move the ota to access these. Locate the two lower hex bolts inside the bottom hand recess and loosen them but don't remove. The outer plastic cover should now come off revealing the motor assembly (see image). Look for the two small black phillips screws that secure the gearbox to a shiny silver pressed steel bracket (see image). Note that there is a gap between the bracket and gearbox and this is where the O rings will be placed. Remove one screw and slide an O ring in place, replace the screw and tighten slightly to put pressure on the O ring but not to significantly distort it. Repeat with the next screw. While the side plate is off, now would be a good time to replace the grease on the main brass worm and large cog with something suitable like lithium grease. That's it! Simply replace the cover and clutch knob and things should be quieter.