I use Astap in voyager. I used On the Fly to plate solve a FITs. It shows PA of 93.5 (which seemed right). Blind solved provides the same answer. However when using ASTAP direct, there is this small arrow (which I think is PA) with -86.5 next to it. I’m surprised it is different, almost if something was flipped : 93.5 - 180 = 86.5. but why if ASTAP is used in both cases ?
Are both fits taken with the same software? Has one been software rotated or flipped?
Voyager not use negative PA, value is normalized used the WCS matrix