Hello all,

I am currently in an imaging session and will pull the logs later.

My mount is an HEQ5 Pro w/ rowan belt mod

I am noticing that my calibration plot looks terrible and my Dec guiding seems to drift off by a lot in the beginning. Then it will do it every so often in the middle of the sessions as well.

Dec seems to be completely drifting away after every dither.

1) What does the terrible calibration graph show/mean? Should I be adjusting worm mesh etc?
2). Does it really matter how bad my calib. graph looks?

I tried to turn of dec calibration however it had done the same exact thing. Images are below. Scope details are correct. I am using 3" exposures binned 2x2. Guiding rate is correct etc.

I added Dec and RA calibration Image below. The calib. graph looks pretty bad.




Dec & RA

Hard to tell, here are a few generic things:
- make sure your mount is balanced and the mount doesn't feel too loose when you try to move it by hand in the RA and DEC directions.
- it should "sound reasonable" when you slew both motors
- no large cable drags,
- calibrate a bit more aggressively, that is, use something like 10 iterations and 1000ms pulses (it will stop at about a 20 pixel deflection, and thus not likely use all 10 iterations)
- use the SEP MultiStar guiding algorithm
- Guiding doesn't work well very close to the pole. Are you very close to it?
- Have a look at the little calibration summary page (see image below) in the guider options menu--are RA and DEC pretty close to orthogonal? What values are you getting for pulse ms/arcsec?
- I personally calibrate once carefully, make sure it's good, and re-use it for months (using the recommendations of the PHD2 folks, e.g. calibrate near the meridian and equator). However, clearly you should first get things working well with calibration before trying that.
- report back with a log.

Also, if these don't help, you might also try using PHD2 and running their diagnostics.

Hope this helps,
Hy

Hi Deesk, hy, everyone

Using EQMOD, I have 'reverse DEC on pier-side...', UN-checked.

@OP I only bin 2 when using an asi120 on an OAG @ 1200mm focal length where it is important to remove the backlash before calibration DEC. There is an option to bump the mount in DEC before calibration. Must have it set although using a 240mm focal length bin 1 guide telescope, it doesn't really matter.

HTH and clear skies,
Steve

Echoing what Hy wrote: Make sure your mount is balanced well in DEC.

It looks like the DEC motor cannot overcome whatever pulls the mount in the other direction. That could also mean that there is too much internal friction which the motors can't overcome. It could also mean that the DEC stepper motor is not well matched to the controller. As a result, microstepping will not work well, while slewing (which generates higher torque) works.

I had a similar problem recently and remeshing the mount ameliorated the problem to some degree.

Jo

Thank you!

I actually inspected the motor and belt closely. I noticed that the belt was jumping and hitting the teeth. That's when I realized I was sent the incorrect size belt. It looks like I was sent a belt for an EQ6 r and not an HEQ5. The teeth on the belt were slightly bigger than they should have been. The RA belt was correct though.

I have a new belt on the way. I also think that I may have loaded the bearing too much as well. I may need to back off some of the tension from the Rowan mod.

So Sorry I never got the logs. I always have trouble with it for some reason. I never did anything for it after the update. I believe I have it sorted out. Its not perfectly along the X and Y axis but both dec and RA seem to be orthogonal...if thats what it is supposed to be? Calib graph looks much better after making adjustments.

Glad things are better. No need to send logs if things are back to working.
Yes, should be roughly orthogonal, though rarely perfectly so (due to measurement noise).

Though they're ~orthogonal, they can be in any direction on the X,Y axis--depends on how your camera is rotated relative to RA--so that's not a problem.

Hy

Yep! It was all good. I had readjusted the worm mesh gear and also reset the belt and added a bit more tension.

No more issues with DEC running off on me. The RA and DEC were also pretty orthogonal. Looked MUCH better compared to my other session. Guiding was hovering around .65-.85 Which was nice.

Thanks for the help! The checklist you gave me helped.