PHD2 Guiding Performance

[Starwiz]

Can anyone tell me how I can qualify the performance of my guiding?

I presume it would be based on the focal length of the telescope, etc.?

I have downloaded the log file viewer, but don't know how to interpret the results.  How good is it and how good does it need to be for the imaging I'm doing?

Thanks

John

 

[alacant]

2 hours ago, Starwiz said:

qualify the performance

Hi

If the images were OK then leave it. Otherwise...

DEC looks as if it could be sticking. Usually it's the cone bearing at the base of DEC where the counterweight shaft fits. Clean and regrease it but don't tighten more than finger loose. Then there's the usual EQ6 periodic error in RA which PHD2's PPEC will all but eliminate.

Don't forget to polar align to around 5' of the pole but remember that, IMHO, the most important factor in guiding, we have no control over; the atmosphere.

Cheers

Edited February 28, 2020 by alacant

[vlaiv]

1.5" - 2" RMS - poor performance suitable only for short focal length wide field shots with resolution 3"/px or lower.

1"-1.5" RMS - suitable for resolution 2-3"/px - wide field work

1" - most of stock mounts can achieve this as good result (on a good night) - suitable for work 2"/px

0.7" - 1" - good guiding, suitable for work at 1.5"/px

0.5-0.7 - very good guiding, suitable for work at 1.2"-1.5"/px

<0.5 - top tier mounts, suitable for high resolution work at 1" - 1.2"/px

Otherwise, I would recommend to deal with DEC backlash. You have very high DEC rms and this is because mount is "loose" in DEC. That level of slack in DEC axis can be felt by hand. If you reduced that with mount tuning, and bring DEC RMS to be equal to that of RA - about 0.55 - total RMS will then be ~0.78 and that is good guiding, on a better side of stock EQ6.

[david_taurus83]

1 hour ago, Starwiz said:

Can anyone tell me how I can qualify the performance of my guiding?

 

Are your stars round???

NO: Investigate for causes of backlash and stiction, adjust if necessary.

YES: Touch nothing and leave it the hell alone!

[Starwiz]

10 hours ago, vlaiv said:

1.5" - 2" RMS - poor performance suitable only for short focal length wide field shots with resolution 3"/px or lower.

1"-1.5" RMS - suitable for resolution 2-3"/px - wide field work

1" - most of stock mounts can achieve this as good result (on a good night) - suitable for work 2"/px

0.7" - 1" - good guiding, suitable for work at 1.5"/px

0.5-0.7 - very good guiding, suitable for work at 1.2"-1.5"/px

<0.5 - top tier mounts, suitable for high resolution work at 1" - 1.2"/px

Otherwise, I would recommend to deal with DEC backlash. You have very high DEC rms and this is because mount is "loose" in DEC. That level of slack in DEC axis can be felt by hand. If you reduced that with mount tuning, and bring DEC RMS to be equal to that of RA - about 0.55 - total RMS will then be ~0.78 and that is good guiding, on a better side of stock EQ6.

Thanks Vlalv, that gives me something to measure it against.

John