Chriske Posted June 23 Share Posted June 23 A long time ago I saw something similar.I kept working on it and came up with this solution to track the stars with a Dob. I added a tracking system based on a few cardan couplings and a thick threaded rod. In the thick wooden beams I added a few rods @51°(polar axis), both in the vertical as well in the horizontal beams. All will be supported by ball bearings. These bearings are all sitting in a printed blocks. Tracking is done with a small motor and two bevel gears. Running time of the unit is about 90minutes. Next week I'll start building one. 5 Link to comment Share on other sites More sharing options...
Dr_Ju_ju Posted June 23 Share Posted June 23 My one suggestion would be to cross-grain the timbers to reduce the amount of wooden flex in differing temperatures etc.... Link to comment Share on other sites More sharing options...
Chriske Posted June 23 Author Share Posted June 23 Just now, Dr_Ju_ju said: My one suggestion would be to cross-grain the timbers to reduce the amount of wooden flex in differing temperatures etc.... 👍 Link to comment Share on other sites More sharing options...
LondonNeil Posted June 23 Share Posted June 23 Nice. Please let us know how you get on. Link to comment Share on other sites More sharing options...
Chriske Posted June 29 Author Share Posted June 29 Not yet started building. A few changes have been applied, has to do with the tracking speed. Instead of bevel gears I'll be using a Worm/wormwheel set. Link to comment Share on other sites More sharing options...
Chriske Posted July 2 Author Share Posted July 2 To be more flexible I'll drop the bevel gears and replace it with a stepper and a Cycloidal Drive. Link to comment Share on other sites More sharing options...
Chriske Posted July 4 Author Share Posted July 4 A few more changes. The two red axis are both fixed. They will be connected by a GT2 belt or maybe a set of gears don't know yet. The cycloidal drive has a reduction of 15x For quick adjusting the polaraxis I'll add a green laser parallel to the upper polar threaded rod. 3 Link to comment Share on other sites More sharing options...
Chriske Posted August 25 Author Share Posted August 25 Some progress ... Mount not finished yet Upper polar axis, threaded rod M16 Lower polar axis, brass axis 12mm Movement... EP04.mp4 Still... drive unit + motor to be installed. 6 Link to comment Share on other sites More sharing options...
LondonNeil Posted August 25 Share Posted August 25 It this design works, it looks very simple to build. Far easier than the usual Dob eq platform with the segments. I'm looking forward to reading how it works for you! Link to comment Share on other sites More sharing options...
AstroKeith Posted August 25 Share Posted August 25 Nice, do you have any photos or detail on the lower bearing? Link to comment Share on other sites More sharing options...
Astrobits Posted August 26 Share Posted August 26 It strikes me that this design will work ( and be easier to build ) for much lower latitudes than the normal Dob equatorial platform. Nigel 1 Link to comment Share on other sites More sharing options...
AstralFields Posted August 27 Share Posted August 27 (edited) I wouldn't say it is easier to build than the typical EQ platform design with segments (all made of plywood without aluminum segments - I have built 4 of them). This looks simple but the top portion with the rods is quite a precision work that I wouldn't be able to do with a simple jigsaw in my garage like I do the segments. Also not sure I can source that motor and transmission on AliExpress But I would say that for lower latitudes this could maybe be a better option. It would be interesting to see one for 33 degrees where the classic design struggles. Either way , looking forward to see this complete. Great project. Edited August 27 by AstralFields 1 Link to comment Share on other sites More sharing options...
Chriske Posted August 28 Author Share Posted August 28 Forgot to mention. In the most upper (printed) part there's room for a laserpointer to align the unit to the north. In that part the hole for the major (M16) bolt and the hole for the laser are printed in one piece, so I can set it up very accurately. The laser is adjusted in a lathe. Link to comment Share on other sites More sharing options...
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