Hi all.
I've been guiding on an EQ5 pro mount with a Samyang 135mm with an ASIAIR plus for the last month or so.
In general terms I've been reasonably happy with it, even though my DEC line misbehaves frequently and takes many pulses (and a fairly long time) to recover from various excursions that it makes.
Some nights I can get to around 0.7RMS but never below. Last night I was above 2RMS most of the night.
I suspect a problem with stiction &/or backlash in my DEC axis. Various settings changes in the AAP don't really make a huge difference but I am gradually trying to see if I can get to a minimum RMS before attempting to physically adjust the mount.
In any event, I can still attain ok images for the most part I think
However at the end of last night's session, bizarre and extreme excursions occurred, with DEC & RA both going off the charts in opposite directions at the same instant.
A couple of things I notice(bear in mind I am new to this)..
The SNR dips slightly at the times of the large excursions. However, similar SNR dips do not coincide with excursions.
Not only do RA & DEC coincide in time and duration, but the graphical shape of the excursions in both axes are identical..
Viewing the guidecam screen, I could see the guide stars visibly drifting. It was like tracking had suddenly turned off or something but it seemed to be still turned on within the ASI app.
I have attached last nights guidelog as well as 2 screenshots of the incident(for those unable to view the log).
Any help or suggestions would be greatly appreciated.
Samyang 135mm @F2.8
EQ5-Pro
Canon 700D (modified)
ASIAIR Plus
ASI120mm guide camera
ZWO 30mm F4 Mini Guidescope
If I have not included enough info to diagnose potential issues please let me know.
Many thanks in advance
