Weird DEC spikes while guiding on EQ3-2.
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Ovidiu Dascalu
Dec 2, 2021, 5:31:00 PM12/2/21
to Open PHD Guiding
Hello! I've had this problem intermittently for a while now and I finally decided to ask here for help. Sometimes while imaging the DEC would spike 2-16" and then come back down by itself after a minute or so. Last imagining session this led to a lot of trailed subs. I have attached below a screenshot of what I'm talking about and the logs. My setup consists of a SW72ED, Canon 60D ,ZWO 120MM + 30mm guide scope, all mounted on an EQ3-2 with Enhanced dual motor kit. I would be really grateful if someone could help me fix this. 
Brian Valente
Dec 2, 2021, 5:47:32 PM12/2/21
to Open PHD Guiding
Hi Ovidiu
We can give you some feedback and tips, but i think fixing it is going to require some work on your mount, sorry
First a couple tips: it would be better if you used pulse guiding via an ascom driver for your mount, such as EQMod. ST-4 connection you are currently using has some significant drawbacks, including not having much information about your pointing position
Second, you should do a guiding assistant run to measure your
On the guide log itself, your calibration shows one of the big issues.
Your Dec steps look about 1/4 the mount of your RA. Some of this could be your sky position when calibrating, but likely there's some other issue. Make sure you get a clean calibration by following the baseline guiding steps here: https://www.dropbox.com/s/zrf0au7jaisvt85/How%20to%20create%20a%20baseline%20for%20guiding%20results%20using%20OpenPHD2.pdf?dl=0
When guiding, you have extremely high amount of Dec backlash, as shown here:
When you address your calibration issues, this will probably clean up a bit, but you still have a lot of backlash. Chances are you will need to make an adjustment on your mount axis.
You should also enable auto backlash compensation in Dec and use a max value of 2500. you can start with a backlash value of 1200 and it will correct itself.
this won't fix your problem, but all the above should make things a lot better, at least from a PHD perspective
good luck
Brian
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