I have SkySafari Pro, two friends of mine have SkySafari Plus. When looking at Comet Wirtanen we noticed that in the Plus the magnitude was 8.8 but in Pro it was 3.8. All other data seemed to match. Any reason the Plus was so different?


I have SkySafari Pro, two friends of mine have SkySafari Plus. When looking at Comet Wirtanen we noticed that in the Plus the magnitude was 8.8 but in Pro it was 3.8. All other data seemed to match. Any reason the Plus was so different?


The problem is beyond that, not just the 6 pro and 6 plus.
Sky Safari 4 plus (android ) shows +8.8.
Sky Safari 6 free (android ) shows +3.8.
Sky Safari 6 AR (iOS) shows +8.8.
Yes I can confirm the incorrect magnitude on my SkySafari plus 6.3
The MPC gives an absolute magnitude of 14 mag and a slope parameter of 15 (6*2,5) for the comet. These parameters are absolutly wrong for the current observations. What is the reason for this? I don't know.
Via Seiichi Yoshida Homepage and the yahoo comets mailing list the true parameters are:
m1 = 8.0 + 5 log d + 27.0 log r(t - 12) [-150, 180] (2018 July 15 - 2019 June 10)
M=14 mag -> 8.8 mag
M= 8.0 mag -> 3.8 mag
I know this is an old post but I thought I would answer. I am very sure this is not a bug in SkySafari. There are two possibilities.
1. The last time you updated the Minor Body Orbit Data in Plus is different from Pro. That means they might be working with different data from the Minor Planet Center.
2. You are not in the same location on the two apps. If you are orbiting a different object in Plus and are not on Earth, that could explain a difference. All data is presented from the point of view of where you are located.
I don't think it is #2 in your case since the distance to the comet is the same in both cases. I can only guess #1 must be at play.