AZ-EQ6 Clutch slipping in the cold?

[bugeater]

I set my outfit to take shots last night for 2 hours, came back and found only 5 of the 5min images okay. The next two are smeared with star trails and then the last ones are of a completely different part of the sky where it seems to have stabilised.

Its a AZ-EQ6 and running EQMOD and PHD2.

My guess is that the clutch slipped, possibly because it was so damn cold (it was around 0.5 degree when I went out to pack it all up and there was ice on stuff).

But I'd like to check if anyone else has had this sort of thing happen to them before.

I gather the ubiquitous EQ6 has a similar type of clutch. I did check the RA dial after parking and it did look like it was a little off, but I'm not sure if that's normal or not (I always begin a session with it lined up).

[The_bluester]

I have never had mine slip noticeably though I have found a couple of times where I could move the scope by bumping it and making the RA clutch slip. I think the EQ6 clutch is more positive in operation and you need to be a little firmer with the tension on the AZEQ.

I have never had it fail to track though, but mine is used visually so not set up and left unattended for potentially hours at a time.

[AlexN]

More likely is that it has lost the guide star then locked onto a different star later. Either that or you had cables snag somewhere that caused the clutch to slip

[bugeater]

I did consider it could be due to it losing the guide star, but that seems like a pretty catastrophic response. Essentially drifting in a linear manner for over 10 minutes.
Guess I'll have see if it repeats itself next session. Still not entirely happy with the setup on the OAG and the qhy5, so it is my second hypothesis :)

I'll note it was very very cold with ice forming on stuff - don't know how the clutches work, but I could imagine it's not positive for their operation

[AlexN]

I have had mounts operating well beyond -5 in the past without problems.

Usually speaking, if your guiding fails your drift will be linear unless you have some gross periodic error.

[rustigsmed]

I had similar things happen with the eq8 over the w'end, the coldest weather I've used it in. my return rate for subs was quite terrible. I was going to put it down to me setting up when exhausted and therefore a more shonky polar alignment than usual but perhaps the cold required clutches etc to be tighter (although I usually have them pretty tight). I don't know though, last night I decided to realign with some more care (left scope out all w'end) and it was shooting M16 like a champ - dead on, however after I shifted to ngc 6559 it was hot and cold (and they aren't that far apart in the sky) in fact I gave up on it and went to corona australis.

[bugeater]

Yeah it's weird. I too was shooting M16 on Saturday night till it went behind trees, then switched to the NGC 253 and went to bed. It all ran fantastic despite the cold. Left the gear out over Sunday and thought Sunday night would be straightforward, but clouds and then this smearing problem meant I only got 5 x 300s subs of M16.
I guess I'll just pay extra attention next time.