Hi folks, quick question it has taken me years to think off asking!
With any three star model my old mount (Vixen Atlux and SkySensor2000-PC) can correct for polar misalignment of up to 20 degrees - it simply runs both motors at correction rates it solves mathematically for all over sky pointing - including atmospheric refraction - but what if it's a tiny bit wrong I just wondered...
I wonder now if I should turn off my mount's polar misalignment correction capabilities whenever I am:
- polar aligning my permanent rig by any drift or T-point method and
- when doing guided imaging - as seeing versus real drift vs mount corrections could all cause slight see saws in my tracking.
I only realised now there could be a small feedback loop causing some extra difficulty for the guiding - where the mount corrects in anticipation for expected polar misalignment and possibly at times being a bit ahead or behind optimal gear movement to keep the star centred it might be worsening the guiding slightly...
I was pondering why subsequent TSX 300 star models gave slightly different polar correction advice - normally adjustments less than 2 arc minutes on one or both axes. So I might do two subsequent runs - one straight after the other - only noting the correction advice - not implementing it - and see if between subsequent runs (with a new supermodel each time - complicating things possibly) whether the polar correction advice was consistent or not - it was slightly off - normally only in East / West corrections.
Given I have a permanently set up rig - I wonder if I might be best to only do a 1 or 2 star align in my hand controller - to avoid triggering the SS2K's polar misalignment function (or do a three star model - but just click accept on the third star - without any re-centring on the third star even if it is a few arc minutes of dead centre) - then use TSX closed loop slew or NINA or SGP to centre on any target and then use PHD2 to track.
Does that make sense to folk -any suggestions?