Interpreting Guide Log...help! :)

[BeneathTheStars]

Hello everyone, 

I'm trying to get to grips with guiding in PHD2.   This is the second time that I've used it and I'm trying to understand what my Guide Log is showing me.  I have a total RMS error of 4.96" and I'm keen to understand more about where this may be coming from.  In particular, I wondered if the log can indicate issues with balance?   Hopefully I have successfully attached the my Guide Log below, I ran the Guide Assistant for 10 minutes during this session then applied the recommendations which PHD2  made.   I am using an HEQ5 with belt modification.  Any words of wisdom would be greatly appreciated.  

Thanks for your time!

 

https://openphdguiding.org/logs/dl/PHD2_logs_KKUp.zip

[kens]

Have you got PHDLogViewer installed? If not you can download it https://adgsoftware.com/phd2utils/

The first thing I noticed is that your guide rates are set at the EQMOD defualt of 0.1x sidereal (or 1.5"/s) which is way too slow. Incerase the guide rate to somewhere between 0.5x and 0.9x sidereal. You will need to recalculate the calibration step size as a result.

The other thing to check is the focal length of your guide scope. It has been entered as 50mm but I think that is the aperture, not the focal length. As a result, your guide RMS in arcseconds would be way off. The guiding RMS of 0.3 pixels is quite reasonable.

Overall, I would suggest that you sort out the guide rate and guide scope focal length and create a new profile in PHD2 with the wizard. Then try again.

[malc-c]

Hi Claire,

I agree,  there are some incorrect information entered so the calculation of RMS etc will be out.  I've looked back at your previous post and see that you are using an HEQ5 and possibly an ED80, can you confirm (most of us place details of our equipment as a signature in our profiles as it helps others provide assistance ).   The log suggest a QHY5LII-C guide camera, and I presume you are using the Canon dSLR mentioned in a previous post as your main imaging camera.

I'm no expert on deciphering the logs files, but form what I can see your calibration was good, with little or no backlash.  But a calibration step of 10750ms is quite a long time....

The 50mm focal length stated would be a very short guidescope   - this needs to be corrected to the focal length and not the objective of the guidescope. 

Other than that for me the RMS values are irrelevant as its calculated based on the focal length and camera pixel size.  But both DEC and RA are trending in the same flat plane over the 4hrs of guiding.  There are quite a few members who can give you more feedback so I'll leave my comments at that

 

[michael8554]

As above - wrong focal length.

Also Polar alignment poor:  PA error = 9.1 arcmins.

You need to get that down to 5arcmins at least.

Also you have the PulseGuide Setting too low in EQMOD:

RA Guide Speed = 1.5 a-s/s, Dec Guide Speed = 1.5 a-s/s

Guide speeds need to be at least 7.5arcsec/sec.

Your guiding might actually be quite good, RA and Dec errors are very similar, so you should have round stars.

But the incorrect settings are causing PHD2 to multiply the error figures.

Michael

 

[wimvb]

10 hours ago, michael8554 said:

Also Polar alignment poor:  PA error = 9.1 arcmins.

If the focal length is wrong, then any result in arc seconds or arc minutes is also wrong. The op needs to correct this first.