Stellarium accuracy

[Kirscovitch]

Love the program! Many nights I use it to stalk my next targets for an upcoming viewing session. 

My question though is how accurate is the software for finer details such as the transition of the GSR? 

[ronin]

For something like the GRS I suspect the answer is "reasonably accurate".

The reason I say that is because the GRS is a Jovian weather feature, not a "fixed" astronomical one.

It's size will give it some stability and regularity but it is still weather.

[Kirscovitch]

Good point. I have searched the web and found numerous sites that will give you the transit time and they are "off" from what stellarium says. 

But like you said its a weather feature so how do these other sites predict the transit? 

[ArmyAirForce]

There was a thread somewhere on here about resetting the position of the GRS in Stellarium, as it has drifted with time, and will continue to do so. I don't know if later versions of the software have re-set the location making it more accurate again.

[kev]

How about using winjupos?

[Ptarmigan]

are "off" from what stellarium says. 

... its a weather feature

Yep, because it is a variable weather feature Stellarium needs to be told where the GRS is "now" ie. you need to adjust your Stellarium for where it is now compared to where it was when your version of Stellarium was compiled and downloaded/installed.

So :-

1) you need to search your HD for a Stellarium file called ssystem.ini

There may be several of these on your disk and you will need to mess with them each in turn to find the right one !

most likely it will be summat like ...\(YourUserName\Roaming\...AppData\Stellarium\ssystem.ini

But dont worry, try them each in turn till you find the right one !

2)Open that file in a text ed. such as Notepad or Wordpad

whizz down to the [jupiter] section

find the line that says  rot_rotation_offset = (some number nnn)

and change nnn to sumat else like mmm where mmm is between 000 and 359 by trial and error until the GRS is where it is supposed to be

:-   you will need to close and restart Stellarium between each trial and error !

Then Stellarium will be good till the GRS blows off to somewhere else on Jupiter

Probably easier just to use the Sky&Telescope predictions !!

[Kirscovitch]

I have checked the Sky&Telescope site. Just haven't been able to get out at those times to see if the spot is visible. I just noticed that if i get the time from S&T and then check with Stellarium, they never match.

[Ptarmigan]

rot_rotation_offset =75

seems to be about right in my Stellarium 11.1

but my portable Stellarium 12.4 seems to want rot_rotation_offset =200

! odd !