3 replies to this topic

[piompero]

Hi.
I would like to ask for advice on an important problem that my AZEQ6 mount has been giving me for a few nights.
It is a problem on the declination axis. You can see in the PHD graph that suddenly the dec axis goes away and when the program tries to correct it, it cannot, until after a while the axis moves to the other side again and the same thing happens again.
The RMS of DEC is twice that of AR.
It had never happened to me and I don't know what it could be.
Maybe I have something wrong configured in PHD or maybe it is a mechanical problem with the mount. The fact is that when it is working it seems all normal, the noise made by the mount is normal and there does not seem to be any problem with the mount's motors.
Thanks for your possible contributions.
A greeting.

 

[John Miele]

Interesting...a sudden case of DEC backlash...maybe the DEC worm has come a bit loose...possibly a set screw slipped a bit or a retaining nut has slightly backed off soemwhere...do you guide DEC heavy on the camera end? I'll bet it is a simple adjustment if you can just figure out what to adjust...that's always the hard part...lol!

[1DegreeN]

I have the AZ EQ6 and have a similar issue with apparent stiction in DEC, although curiously only when the scope is pointing west and then mainly after a dither. I've never found the reason but I haven't lost any frames due to it so I haven't done a thorough investigation. On your screenshot it shows RA and DEC rates of 1.4" per second - are you using EQMOD with the pulse guide rate parameters set to 0.1?  If so, that is a bit low and a rate of 0.5 to 0.9 is usually recommended. I have mine set to 0.9 

I see that you are using the latest dev release of PHD2 which has multi-star guiding. I've been using multi-star guiding since it was released and it works very well with my AZ EQ6. Multi-star guiding allows a shorter exposure and I use a 1 second exposure on mine (I see you use 2 second exposures). Increasing the EQMOD guide rate and decreasing the PHD2 exposure interval will not stop your DEC excursions but it may enable PHD2 to recover more quickly.

[piompero]

Thank you very much for your answers and advice.
Yes, I actually guide with eqmod and the pulse guide rate is 0.1. I always thought that that was very little and very strange, but since I was doing well, I left it like that. I'm going to try raising this value.