PHD2 Guiding issues(#7) and learnings (#8)

I'm referring to my earlier blog (First light with Guiding Scope TS 50x180) in which I described my issues during guiding with PHD2.

Issues, learnings and solutions.

1) Focussing of Guiding Scope (#3 issues)

#1 I found out that my Guiding Scope was not focussed at all. After adjusting the scope, more and sharper stars became visible. 

#2 As a next step, I arranged that the center of the guide scope is the same as the center of my telescope.

#3 During testing I found out that the cable connected to the guide scope was changing focus resulting in an out of focus view.  

2) Polarallignment (#1 issue)

#4 My collegue, Walter from Helios Astronomy Club, informed me to use polarallignment using SharpCap. I assumed that my visual polarallignment was quit good (I did last year a comparison test with QHY PoleMaster with good results). I watched a couple of video's and to my opinion the best one was from The Lazy Geek. The polarallignment process was reapplied realizing an "excellent" score. The polarallignment was first done with my guiding scope (with ASI290MM) and then using the main telescope (with ASI2600MC). Results matched perfectly: see screenshots below

3) PHD (#3 issues)

#5 My profile in PHD2 was still set on my other guide scope "miniscope". According to some forums the best way to (re)start is to create a new profile and to start from scratch. So I made a new profile for my TS 50x180 guide scope.

#6 I read about multistar allignement but did never used it. This time I enabled this option. In order to use it, you need to select "autostar".

#7 After completion of the calibration process it's an option to use the "guiding assistance". I completed the guiding assistance option and "applied" all settings. I foud out that the backlash wasn't that good. I decoupled my telescope and marked the tipping point of my set up. After reinstalling my telescope I restarted the entire process inlcuding the guiding assistance tool. This time the backlash was better but still not "ideal". See printscreens below

Results and conclusion.

1) Good guiding results with a guiding error below 0,25px. However the second session had a guiding error below 0,75 px. The first session had a very stable and flat guiding pattern. See below printscreen

2) Polarallignment using SharpCap is easy and seems very accurate. My setup will be adjusted including this new step and way of working.

3) Focussing of guiding scope and cable management is a watch out. 

4) Backlash was found to be an issue. Out of 3 sessions, I had twice an issue. This remains an open item.

5) I could make pictures with exposure times of 10 minutes. The image is good and the stars are round. See picture below of M57 with 2x10minutes exposure time - stacking done using APP.

6) 3-star allignment is done after polarallignment. Via EQMOD my mount is connected to Stellarium
 

7) It's not clear if I need to recalibrate before each astro-imaging session. This is something I need to find out. For now, I will do the calibration each time I set up my scope. 

8) One more topic is about the calibration session itself. It's recommended to do the calibration near the equator and around the meridian as stars move fastest in this region. This is something I need to foresee aswell.