red dwalf Posted May 3, 2014 Share Posted May 3, 2014 tried to image M101 last night, scope was almost vertical but for some strange reason i couldn`t get PHD version 1.14 to work properly, the guide camera, ZWO 120MM, was set at 1 second shots as usual and was showing a number of stars, but when i locked onto a star and Phd was doing it`s magic the stars started to flash up on the screen in a different place to which they were at first causing the PHD graph to go crazy trying to look for the star that was in the green box but had now jumped across to another part of the screen, anyone had a problem like this before ? gave up on M101 after an hour and a half and moved over to M13 where PHD dide the same again and then started to behave it`s self although it still lost the guide star once or twice. Link to comment Share on other sites More sharing options...
+RonC Posted May 3, 2014 Share Posted May 3, 2014 (edited) That's a new one on me Rob, normally stars or no stars, not flashing stars!! Check on SGL?? Ron (who's PHD did run on M101!) Edited May 3, 2014 by Ron Clarke Link to comment Share on other sites More sharing options...
red dwalf Posted May 3, 2014 Author Share Posted May 3, 2014 stars were there Ron but virtually every time the camera refreshed the image the stars had moved, almost as if the mount wasn`t tracking at all, but then they would move back but never back into the green box on PHD Link to comment Share on other sites More sharing options...
+RonC Posted May 3, 2014 Share Posted May 3, 2014 Very strange! Might be worth checking tonight if it's clear, connections etc.. Link to comment Share on other sites More sharing options...
Guest Kheldar Posted May 3, 2014 Share Posted May 3, 2014 Play in one axis maybe? Link to comment Share on other sites More sharing options...
Astrocookie Posted May 3, 2014 Share Posted May 3, 2014 That's a new one on me Rob, normally stars or no stars, not flashing stars!! Check on SGL?? Ron (who's PHD did run on M101!) T'was I trying to image M101 at Wymeswold. Wasn't a PHD problem though... just coulodn't find it Rob. I had a problem like this once when the RA cog was slipping. The imaged jumped each time the cog jumped a tooth. Funnily enough this was when the scope was almost vertical.. I put it down to the balance being out. Good luck Paul Link to comment Share on other sites More sharing options...
Guest VikN46 Posted May 3, 2014 Share Posted May 3, 2014 Hi, last night I couldn't get PHD 1 (1.14.2) or PHD 2 to work either, it locked on to a star and there were plenty to choose from and it calibrated but didn't follow the star at all! Very frustrating Link to comment Share on other sites More sharing options...
red dwalf Posted May 3, 2014 Author Share Posted May 3, 2014 couldn`t feel any play in the axis Stephen, thought it may be a balancing thing so adjusted that even though it was only tiny bit weight heavy, my other suspect was a cog catching but how can you tell unless you take it apart Link to comment Share on other sites More sharing options...
xanthic Posted May 3, 2014 Share Posted May 3, 2014 I thought for guiding there ought to be some positve weight on the system, so it doesn't float about? I had problems calibrating whilst I was doing M81. Maybe problematic near zenith? Link to comment Share on other sites More sharing options...
+RonC Posted May 3, 2014 Share Posted May 3, 2014 My set-up is just off balance and no problem with M101 last night at the zenith.. Link to comment Share on other sites More sharing options...
+Graham Posted May 3, 2014 Share Posted May 3, 2014 Almost certainly backlash on the gear train between the motor and the primary drive gear.. If the scope was vertical it will rock on the gear train until it gets to a point when the balance can resume a load effect on the gears again. The reason it does not affect Ron is because he has had a belt mod fitted. My mount is terrible for it. Link to comment Share on other sites More sharing options...
red dwalf Posted May 3, 2014 Author Share Posted May 3, 2014 cheers Graham, the scope was just about vertical in fact after trying to restart the set up from the home position again the mount and scope went to the oposite side to the first time, should i therefore increase alittle more weight onto the counter bar side to combat the backlash ? Link to comment Share on other sites More sharing options...
+Ibbo Posted May 3, 2014 Share Posted May 3, 2014 yes I would try that also make sure one end of the scope is a bit heavy as well Link to comment Share on other sites More sharing options...
red dwalf Posted May 3, 2014 Author Share Posted May 3, 2014 will do, cheers Link to comment Share on other sites More sharing options...
+Graham Posted May 3, 2014 Share Posted May 3, 2014 you will probably find the backlash is in the DEC axis. Once the scope reached vertical no matter which end is heavy it will still rock on the gears until it goes past the balance point. As Steve says if you set the rig up camera heavy it will reduce the time that the scope will rock on the gears whilst at the vertical position. Link to comment Share on other sites More sharing options...
red dwalf Posted May 3, 2014 Author Share Posted May 3, 2014 thanks Graham, will give it a try Link to comment Share on other sites More sharing options...
+RonC Posted May 4, 2014 Share Posted May 4, 2014 Just thought Rob, my mount is belt driven (thanks to Graham!) which might make a difference?? Link to comment Share on other sites More sharing options...
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