Hi Jasem, first the align model is working very well, I have checked that with PHD2 drift align and I am really closer than I was before.
Also I can make longer exposures without drift. I was guiding with 0.5" (both RA and DEC) and now I am on 0.4" (RA)/0.2"(DEC) so I it's really a big improvement.
The issue is only the first positioning of the mount, If made manually there's no problem. Thank you for this method, it really helps.
The following user(s) said Thank You: Jasem Mutlaq
I tested the alignment method yesterday. Just a simple remark. When a slowing orientation (west or east) is chosen at first rotation it remained not set at second rotation.
Anyway I didn't had enough time to test the accuracy as the clouds went to ruin the rest of the night.
I still have this strange issue with what appears to be a meridian flip while doing alignment.
Before I did the alignment I slew the mount to EAST a bit more than 90 deg° in RA to be sure to have enough space to do two 15° slews to WEST without meridian flip.
I recorded a session with two alignments, the first worked, it did the 15° deg. west rotations without going to the other side.
The second (to prove the accuracy) was far off and it did? a meridian flip although I started at roughly the same RA as in the first alignment... Maybe I am to stupid and should read "Telescope for dummies" again, especially section meridian flip
If someone finds a reason why the second alignment did slew to the other side and why the result is so far off from the first one please let me know
Also, I noticed from the video when you recheck, you manually go back to the beginning and start again. No need. just start again from where you are, but reverse the direction (i.e. east instead of West), and you're set!
Note that after first run your mount remembers 3 alignment points (based on 3 resolved captures), next you adjust the mount manually with screws, so these alignment points are not valid anymore, but probably are used in the next run of the procedure. Can you check on your mount's Align tab how many points are used before the second run? I believe it might be the root cause of this issue in some circumstances. In such a case it's enough to clear all the points before the second run.
I've been toying with PAA, CCD Simulator and Telescope Simulator from the git repository and after completing the process I always get about 5' 40' - 5' 50' of PA error. In fact, the same behaviour can be seen in Jasem's video (watch it from 5:10 onwards):
As you can see, there's a PA error of 5' 41".
In my mind, both CCD Simulator and Telescope simulator should be "perfect" and have 0 PA.