LAW
19-08-2012, 10:07 AM
Hey everyone, I picked up a cheap second hand EQ5 and it's been great, I've been working through Suzy's lists as well as a few planets and such but I'm starting to notice some limitations.
I've noticed a lot of backlash in the gears as well as irregular movement in slow motion, it feels like the shaft might be bent? It gets intermittently easier and harder to turn on the RA axis. And towards the zenith the DEC slow motion control seems to disconnect itself? The handle just freespins but the clutch holds until I move to a lower RA. :shrug:
Also the motor drives take a long time to change direction, if I overshoot a target or go the wrong way (this happens more than I'm willing to admit) I have to run the motors at full speed for a few seconds to take up the slack before it starts to move, and then the easy/hard temperament of the gears makes it track at varying speeds so things tend to slowly wobble in a 6mm EP.
I pulled the motor drives out to see if I could find where the slack was coming from but it's a sealed unit, I did notice that the 'rack' gears on the axis are very worn. It looks like the steel worm gear has chewed through the aluminium rack gears. Is it possible to replace these as there isn't much 'tread' left?
Overall I'm very happy with the mount for the price I paid, but as an aircraft engineer I get a little OCD when things aren't perfect. I'd really like to modify the motor drives for PHD guiding via the 'Shoestring Astronomy' ST4 thingo, but I don't think the mount is precise enough in it's current state to benefit from guiding.
[EDIT] While I think of it, can I use a canon 450D with liveview as a guide camera in PHD? I have a Philips SPC900NC webcam which has been modified with a 1.25" adapter but the picture is so dark it can't pick up any stars, it even struggles to see the moon. From all accounts this is supposed to be quite a good webcam, what am I doing wrong?
I've noticed a lot of backlash in the gears as well as irregular movement in slow motion, it feels like the shaft might be bent? It gets intermittently easier and harder to turn on the RA axis. And towards the zenith the DEC slow motion control seems to disconnect itself? The handle just freespins but the clutch holds until I move to a lower RA. :shrug:
Also the motor drives take a long time to change direction, if I overshoot a target or go the wrong way (this happens more than I'm willing to admit) I have to run the motors at full speed for a few seconds to take up the slack before it starts to move, and then the easy/hard temperament of the gears makes it track at varying speeds so things tend to slowly wobble in a 6mm EP.
I pulled the motor drives out to see if I could find where the slack was coming from but it's a sealed unit, I did notice that the 'rack' gears on the axis are very worn. It looks like the steel worm gear has chewed through the aluminium rack gears. Is it possible to replace these as there isn't much 'tread' left?
Overall I'm very happy with the mount for the price I paid, but as an aircraft engineer I get a little OCD when things aren't perfect. I'd really like to modify the motor drives for PHD guiding via the 'Shoestring Astronomy' ST4 thingo, but I don't think the mount is precise enough in it's current state to benefit from guiding.
[EDIT] While I think of it, can I use a canon 450D with liveview as a guide camera in PHD? I have a Philips SPC900NC webcam which has been modified with a 1.25" adapter but the picture is so dark it can't pick up any stars, it even struggles to see the moon. From all accounts this is supposed to be quite a good webcam, what am I doing wrong?