Poor guiding graph on EQ6-R PRO

[Luca Bartolucci]

Hello everyone,

First of all, I’d like to thank those who helped me last year with my first post about the guiding issue with my Bresser. Since November 2025, I managed to buy a new SkyWatcher EQ6-R PRO mount, keeping the following equipment: RC 6” telescope, off-axis guider, Canon EOS 700D as imaging camera, and ASI 120MM Mini as guide camera.
I’m writing again because I need help — I can’t seem to get a decent guiding graph in PHD2 to take satisfying photos. Since I got this new mount, I’ve never been able to get a decent graph.
At first I thought it might be the polar alignment not being accurate, then I moved on to balancing the DEC axis, but nothing worked. In particular, during my last sessions at the end of February, I achieved a really good DEC balance by adding a small counterweight on one side of the telescope.
Below you’ll find a link to the PHD2 log file:

https://openphdguiding.org/logs/dl/PHD2_logs_uFXw.zip. 

I’ve shared multiple guiding sessions along with the related Guide Assistant reports. I’ve also tried adjusting several parameters such as hysteresis, aggressiveness, minimum move, and calibration step size.

In your opinion, should I send it in for service to have it maintained?

Thank you in advance for your help!
Best regards.

[Michael Waring]

1.  You probably have the "EQMOD ASCOM Pulseguide setting" on the default setting, which is too low:

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

Needs to be at least 7.5arcsec/sec.

Don't alter the PHD2 Calibration Step Size once you've corrected the EQMOD setting, 

You may need to create a new Equipment Profile to regain the correct setting.

2.  "GA Result - Recommendation: Backlash is >= 19128 ms; you may need to guide in only one Dec direction (currently Sud)"

Dec worm needs adjusting.

Michael

Wiltshire UK

[Frederic Ruciak]

Hi, I had an EQ6R Pro and the guiding improved a lot once properly tuned (consistently 0.4 to 0.6" RMS ). You have two categories of issues: everything related to the guiding itself (eqmod, PHD2, calibration, parameters settings, ...) that I will not comment besides the expert of the group, (I'm an old guy I read the manual and everything related to eqmod extensively). And you have the  mechanical tuning of the EQ6R. On my own I dismounted it and changed all the bearings but it is not necessary to get 80 to 90% of the benefits. First of all you you have to check if your mount is moving smoothly on both axis. When balanced withou clampling RA or DEC, the axis have to move smoothly withou any effort, just a small push is sufficient to trigger a wide rotation. If not your mount has been delivered with too much torque on the axis compressing the bearings. This is almost systematic from SW. There are plenty of good tutorials on youtube like the ones of astrobloke or this one https://www.youtube.com/watch?v=0yzFTjlpZaI&t=472s. The second main thing to tune is the backlash for the DEC axis. This video  https://www.youtube.com/watch?v=rEgkPA-Cd84&t=1858s is very clear you do not need to dismount but the way to test that there is no blockiing point is very good. That way you can achieve the least backlash without blockiing point. When you tune the little screws that adjust the backlash you have to do very small move (1/16 of a turn) and be patient. It is worth to do it. On my mount these adjustements made a HUGE difference.

Hope this helps.

CS Frédéric

[Bruce Waddington]

Things would go better for you if you followed best practices and used the Calibration Assistant.  Follow all of its instructions especially increasing the guide speed setting in the mount driver to 0.9x sidereal.  Because this guide speed setting is so low, there's really not much we can tell you about the mount, including the huge apparent backlash.  It also seems that your guide camera was picking up only a single guide star, so I don't know if that's because of poor guide camera focus or poor skies.  Certainly, that guide camera is perfectly capable of getting better results and should be picking up multiple guide stars most of the time.  I think you should abandon your bad-pixel map and use a newly created dark library to get this sorted out.

Good luck,

Bruce