Quote:
Originally Posted by LAW
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. 
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? |
Well it looks like you found the problem with your eq5 and that being the motor/gear units. You can buy new ones and replace
http://www.bintel.com.au/Mounts---Tr...oductview.aspx or see if anyone has a spare here they could sell you in the WTB section. As for the gears and replacing them in the drive units i have no idea sorry
Maybe google can help if no other users can.
No you can't use live-view to guide
Your Toucam is not sensitive enough to guide with stock really. What you can do is a black and white mod by getting a sony ICX098BL chip and repace the color one you have atm, These cost about $30 plus shipping. The next option is the LX mod for long exposures so you can get .5/1sec exposures for guiding. I don't think you can guide at all with the 900nc without modding because a 1/4 of a sec just isnt enough with a colored sensor
http://www.framos.eu/de/home.html these guys will ship single units of the sensor
there nearly the only ones i know that will, besides commercial stores that will rape you.