LewisM
08-07-2015, 08:04 AM
I set up last night for imaging, and when I had the heaters and mount plugged in to the 12 V DC battery, the battery pack started chirping, indicating it was near drained. No problem - I thought - and plugged it into the charger. It stopped chirping, and everything seemed to be running just fine.
Alignment went well, but then when slewed to target, I noticed RA was still drifting after GOTO (and GOTO had beeped, indicating completion). Thinks I, not backlash, as I had recently readjusted, probably a little too tight in RA if anything. Anyway, it settled soon enough, and I got 90 minutes on target with good tracking.
I then slew to M8/M20, which was almost at zenith at the time. The RA issue returned, this time coupled with the hand controller intermittently flashing like a loose power cable. I tightened all the power connections, just in case a slew had loosened one, and readjusted counterweight bias slightly to load the gears, but no good. PHD couldn't calibrate, and the star drift started increasing in speed.
I tried recentreing target. RA started, then the hand control started dimming again and RA ground to a sudden halt and wouldn't go. I unlocked clutches and put it back in park, and tried RA and Dec movement with the hand controller - Dec seemed normal, but RA started normally again, then stopped. Tried again, and it didn't even try - the hand controller almost went off. Turned it all off and went toprocess what I had gotten, and figure out the issue in the morning.
Now, as I mentioned, I HAD readjusted RA and Dec recently. I had eliminated all backlash in both axes, but the RA seemed to every so slightly bind in a couple spots. When I had adjusted it, I ran the motors full circle (loaded), and no NOTICEABLE binding or even change in motor note.
So, I am hoping to eliminate mechanical, and hope it was merely electrical. Would it be reasonable to suggest that RA required MORE grunt seeing it not only has to rotate on it's axis, but has ALL the weight to push, whereas Dec only has to push the telescope (and NOT the mass and inertia of the counterweights) and SHOULD be less loading on the motor. Therefore, I assume the RA motor is going to draw more from the circuit, and if that circuit is compromised by a low power supply, will show as a problem? (slewing in Dec during the error assessment was NORMAl, perhaps slower than usual, but normal)
I really feel that even though perhaps RA is a TOUCH tight (and I don't really want to fiddle with it again seeing PA is SPOT ON), that the fault lies with the power. I will try a spare battery supply today before tonight, but will also try my regulated AC-DC converter.
Appreciate any thoughts
Alignment went well, but then when slewed to target, I noticed RA was still drifting after GOTO (and GOTO had beeped, indicating completion). Thinks I, not backlash, as I had recently readjusted, probably a little too tight in RA if anything. Anyway, it settled soon enough, and I got 90 minutes on target with good tracking.
I then slew to M8/M20, which was almost at zenith at the time. The RA issue returned, this time coupled with the hand controller intermittently flashing like a loose power cable. I tightened all the power connections, just in case a slew had loosened one, and readjusted counterweight bias slightly to load the gears, but no good. PHD couldn't calibrate, and the star drift started increasing in speed.
I tried recentreing target. RA started, then the hand control started dimming again and RA ground to a sudden halt and wouldn't go. I unlocked clutches and put it back in park, and tried RA and Dec movement with the hand controller - Dec seemed normal, but RA started normally again, then stopped. Tried again, and it didn't even try - the hand controller almost went off. Turned it all off and went toprocess what I had gotten, and figure out the issue in the morning.
Now, as I mentioned, I HAD readjusted RA and Dec recently. I had eliminated all backlash in both axes, but the RA seemed to every so slightly bind in a couple spots. When I had adjusted it, I ran the motors full circle (loaded), and no NOTICEABLE binding or even change in motor note.
So, I am hoping to eliminate mechanical, and hope it was merely electrical. Would it be reasonable to suggest that RA required MORE grunt seeing it not only has to rotate on it's axis, but has ALL the weight to push, whereas Dec only has to push the telescope (and NOT the mass and inertia of the counterweights) and SHOULD be less loading on the motor. Therefore, I assume the RA motor is going to draw more from the circuit, and if that circuit is compromised by a low power supply, will show as a problem? (slewing in Dec during the error assessment was NORMAl, perhaps slower than usual, but normal)
I really feel that even though perhaps RA is a TOUCH tight (and I don't really want to fiddle with it again seeing PA is SPOT ON), that the fault lies with the power. I will try a spare battery supply today before tonight, but will also try my regulated AC-DC converter.
Appreciate any thoughts