PHD2 Runs away in RA

[RicRob65]

Hi, Sorry I expect this is a newbe error but I can't seem to find anything on it. I'm using C11 with a guidescope (QHY5II camera) on an NEQ6 with Starsense hand controller and ASCOM Celestron driver.

For some reason, whenever I start guiding, the graph shows the mount as drifting rapidly east in RA with constant pulses needed to correct it. Calibration seems more or less ok (bit of RA backlash). Perhaps more significant is when I start the guiding assistant (and pulsing stops), the graph shows a vast improvement. It's almost as though the mount either stops sidereal tracking when it's being guided by PHD2 or even is trying to guide east rather than west but is OK when PHD2 is not guiding.

Polar alignment is pretty reasonable using Polemaster.

[knobby]

Did you accept the guide assistant recommended settings ? Might be a guide rate or aggression setting maybe ?

Also check your pixel size and focal length in brain settings.

[RicRob65]

8 minutes ago, knobby said:

Did you accept the guide assistant recommended settings ? Might be a guide rate or aggression setting maybe ?

Also check your pixel size and focal length in brain settings.

That's for your repky knobby. Yes. I did check all those things and tried different aggression settings. Those changes only made little difference compared to the variations seen when guiding is enabled. I probably should have mentioned that Dec is more or less O.K. it's only in RA that I get these large errors.

[alacant]

10 hours ago, RicRob65 said:

the mount either stops sidereal tracking

Hi

Many RA pulses may indicate that the guide speed is too low, the heavy mirror is moving relative to the guide telescope... 

Maybe better to post -a link to- the logs. Otherwise all we can do is guess.

Cheers

Edited April 24, 2021 by alacant

[michael8554]

As Alacant said.

Plus if MinMo is too low then constant pulses will be sent.

How much RA Periodic Error, and PA error, did you see in the Guide Assistant run ?

Log please.

Michael

[RicRob65]

Thanks for the replies so far. A couple of you have been asking for logs. Your looking into them will be very much appreciated. When I get the next clear night and have worked out how to post the log, I will do so.

[michael8554]

PHD2 logs are stored every night in the PHD2 folder on your PC, so you can post now, no need to wait for the next night.

GuideLog, not the DebugLog, and check the date in the filename.

Michael

 

[RicRob65]

23 hours ago, michael8554 said:

PHD2 logs are stored every night in the PHD2 folder on your PC, so you can post now, no need to wait for the next night.

GuideLog, not the DebugLog, and check the date in the filename.

Michael

 

Unfortunately Michael the file(s) are not available.

It wasn't as clear as I would like last night, but I did try again. I set the guide rate to 0.75 on the Starsense handset, and changed the value in PHD2 accordingly. I tried several attempts at calibrating. Sometimes there were very few steps and I got a warning from PHD2 telling me that and what to do. None of the suggestions worked for me. Usually there would be small West steps but each East step was many times larger as though the mount was being pushed in that direction but only when PHD2 has control of it (tracking without PHD2 is quite good but I want better for Astrophotography). It may have been because it wasn't brilliantly clear last night, but often after just 2 or 3 of these large East steps, the star would become lost.

Like I said before, I will be uploading a log when it becomes possible.

Here is a screen shot of what happened the other night starting with when the guiding assistant was on. The mount is generally behaving in RA but as soon as the guiding was applied, it seemed to be constantly drifting east and required west pulses from PHD2 causing much less stable overall tracking.

[michael8554]

Just a small detail.

The screenshots become more meaningful if the Settings are arcsecs instead of pixels on the Y-Axis.

Michael

[RicRob65]

Thanks for your input, We decided to try abandoning the starsense (and it's ASCOM driver) and try the EQMOD route instead. This has resulted in an instant improvement and guiding out of the box to better than 1 arc second without all the constant pushing in RA.