Location-dependant time zones

This is not an "error", but a misunderstanding or a missing feature. To make it clear for future inquiries:

The time shown in Stellarium is your computer's local time, not the local time of the location selected in Stellarium. A location's local time will match Stellarium's displayed time only if that location's time zone matches your computer's time zone. When you use Stellarium to display the sky over locations in other time zones, you should mind the time difference.

You can override the way Stellarium interprets your computer's time by editing the config.ini file. (On Windows XP, it should be in "Documents and Settings/YourUserName/Application Data/Stellarium".) Look for "time_zone" under "[localization]". The default value is "system_default". The accepted values are different for the different systems, but "UTC", "UTC+value" and "UTC-value" should work (without the quotation marks).

When I use UTC instead of system_default instead of system_default, the sky changes but the displayed time does not. Moreover, the sky does not match what should be seen. My system time is US/Central or GMT-6. If I use UTC-6 or UTC-06 or GMT-6 or GMT-06, the sky does not match (by a lot) what I correctly see with system_default. In all cases, the displayed time is my PC system time. I am using 0.10.4 on XPSP3

m kroeger,

Please try UTC+6 and report the result. It seems that there may be a sign error somewhere and time zone offsets are interpreted as their opposites. Also, beware of bug #487232 - after Stellarium starts, press 8 to normalize the time.

Thanks for the suggestion. I'm using 0.10.4 on XPSP3 with ATI Mobility Radeon X1400

I start with system_default. Time = 11PM US/Central. Sky is dark

I set time_zone to UTC+6. Time displayed is 23:02. Sky is close but not the same. Vega and Altair are higher in the East. Appears to be off by an hour.

I set time_zone to UTC+5. Time displayed is 23:07. Sky matches system_default.

I set time_zone back to system_default and checked system time. Windows time is GMT-6 US/Central. Daylight Savings Time confusion?

However, the bigger issue is that although the sky changed to match time_zone (more or less), the displayed time always reported system time. It would seem advisable to never change the time zone away from system time.

Yes, I had seen bug 487232 but pressing 8 did not seem to change anything for me.

It turns out that the value of the "time_zone" field in the configuration file is interpreted as a TZ system variable value, not as the commonly used human-readable "UTC+offset" values.

See here for an explanation of why "UTC-6" doesn't have the expected result:
http://www.gnu.org/s/libc/manual/html_node/TZ-Variable.html

Basically, the "offset" is interpreted as the number of hours that should be _added_ to local time to get UTC.

You can try entering some human-readable time zone name as recognised by the tz utility:
http://en.wikipedia.org/wiki/List_of_tz_database_time_zones
You can try "America/Chicago", perhaps? I am not sure if the time zone names used by tz on Unix/Linux will be recognized on Windows.

Stellarium's user manual most definitely needs to be updated...

Thank you. I tried Europe/London in config.ini. My local (system) time was 8:50 AM (US/Central). Stellarium displayed the local time but the sky was dark! Perhaps, it was shifted back instead of forwards? The easiest solution would be to simply use your system time and convert in your head. Thanks for your help in attempting to resolve the issue.

Stellarium 0.10.5 on Windows XP.
Local timezone = UTC+2 +1(summer)
A few applications do show both UTC and local time correctly, but seems Stellarium is exactly 1 hour ahead.
For example, now it is 22:24 local, 19:24 UTC

If timezone is set to system_default then Stellariim shows the sky for 23:24 local.

The only valid solution was found after a few attempts of setting timezone in config.ini:
time_zone = UTC-4

Of course, Latitude and Longitude are set to my location (Kyyiv, Ukraine, 50N 30E)

P.S. I.m a programmer, but not downloaded sources yet. Please lt me know if you need a portion of code for obtaining UTC time from Windows or any other kind of help.

Anyway, thanks a lot for such a great piece of software!