[g__day (Matthew)]

I am thinking I should likely improve my polar alignment a tad more - as I reckon an initial configuration I did with my mount years ago probably skewed all results done in the past using Tpoint models and drift alignment.

So I run a Vixen Atlux controlled by a Skysensor2000-PC on a pier in my backyard observatory. The setup doesn't allow a view of the SCP - so the Sharpcap Pro / PHD2 accurate align method of rotating around the SCP and plate solving is likely out.

Also there is a bit of backlash in the Dec gears that needs a slight mechanical adjustment that is on my to do list in 2025 - so I have to note and account for this in the alignment method selected.

But the heart of my issue probably goes back to me doing a three reference star alignment with the SS2000-PC when it was set to polar aligned mode. When it is in this state it runs both the RA and Dec motors to account for drift and King rates of refraction as it track objects - so long as you are within 20 degrees of the SCP!

But herein lies the issue - I tried PEMPro polar drift alignment for hours and The SkyX Tpoint using a 500 star model several times - and the adjustment advice each bit of software gave disagreed with itself over multiple runs with no adjustment to the mount given - I just wanted to see if its adjustment advise was consistent or varied over runs - and it wasn't. It may well have been that the SS2000-PC three star model correction algorithm interfered with either or both the Tpoint and drift alignment models some!

Now after multiple nights guiding with PHD2 for many hours at a time - with the SS2000-PC set in a one star alignment mode (so it is not trying to compensate for polar mis-alignment) it reports a polar misalignment around 16 arc minutes - so about 1/2 a Moon diammeter - so I reckon I can and should do much better.

Guiding is pretty good given the mount is carrying 3 Williams Optics refractors - typically around +/- 0.5 arc seconds (with PEC disabled at present).

So I am left with now SS2000-PC isn't interfering - would I be better of polar aligning once and for all with TSX and Tpoint again (using a large sky model) or PEMPro doing a long duration drift alignment. Too now I believe PHD2 has a drift alignment tool - and that software is generally simple and easy to use.

APT also has a alignment tool and so does N.I.N.A. (which I have never used) and SGP is meant to get one soon.

I recall the Bisque team stating all sky alignment with Tpoint gives by far the best polar alignment to the refracted pole - better than drift alignment. But if I really have been half a Moon diammeter out for years - I would really like to improve this - given its a permanent set up.

I could likely use the SS2000-PC Dec Backlash settings to address the discernible slop in the gears (if not doing so may complicate the Tpoint sky model given the Dec backlash to account for) - or just leave it set to 0 as it is at the moment (as that was the advice PHD gave to ensure best guiding).

What would folk recommend I use for my permanent setup and how should I configure (backlash in Dec compensated for or not, drift alignment method using PHD2 or PEMPro or another large Tpoint model)?

Many thanks,

Matt