As I commenced PA with my AVX, an old friend swung by for a chit-chat.
Now I find 4 star PA needs some concentration and chit-chat is very distracting.
As I entered the final Polar Align by adjusting the ALT/AZ knobs I found the pole was WAYYYYY off by about 7 degrees.
WTH? Normally my initial eyeball gets me within a degree at worst.
I was eager to show my skills at this and to get going on exposing.
I repeated the ASPA and got the same results.
OK, lets whitewash over this and get imaging!
I began with 120 secs of M 31 just to show off. I checked for focus and trailing and saw just the usual trailing due to the autoguider not being engaged yet. Then I invoked guiding and demonstrated that the trailing was now gone and the guide star locked solidly.
Old friend was duly impressed. Soon he had to leave.
I continued to image for 50 X 180 sec frames and checked the result. Focus good and no trailing or field rotation. I wasn't happy with alignment but everything was telling me it was OK. Huh?
Later after an excellent series of images and processing I happened to refer to a star atlas to see what I had caught DSOwise around the star Caph in Cassiopeia. To my shame I instantly realized that I had mistaken Caph for Gamma
This explained my PA error. Caph was one of the alignment stars and I had been aligning on Gamma. Doh!!
No wonder the pole was off by about the same distance between Gamma and Caph.
So you can guess what my next comment will be- what's the big deal with accurate PA?
Result as follows on the Perseus Double Cluster. 180 sec X 25 .
Next time out I might just forget the final mount align and do just