PDA

View Full Version : Unimportant question, but question nonetheless.



adavis1992
2010-Jul-25, 05:25 AM
I have been using the program Stellarium to locate objects in the night sky at certain times at my location. Why do things on the program look so much lower in the sky than when viewed in real life? For example, I looked up where Venus was at a certain time when viewed from Dallas and when I viewed it later on that night it seemed so much higher than on the program. Just curious. :eh:

Ken G
2010-Jul-25, 08:48 PM
I'll bet it has to do with the fact that the program displays the sky on a 2D monitor, whereas the sky itself is in essence projected onto a dome.

John Jaksich
2010-Aug-02, 01:51 PM
adavis1992,

I, also, have "Stellarium" on my linux-pc . . . (Ken G's response appears accurate--) but I will weigh in with my response---I believe that all of the coordinates of the stars, planets, etc. , . . might have the same margins of error--if they do, then it is a systematic error of the software---e.g. the wrong coordinates were originally programmed into the software, software error in computing the coordinates, . . .


Personally --I tend to take most software--generated objects with some margin of error --especially when they are not "in real time."

You might try to e-mail or locate the developer(s) --they are based in France--

their address(es) should be in the "help" menu

I can not (openly) give e-mail addresses because of BAUT-forum policy.

grant hutchison
2010-Aug-02, 04:18 PM
... but I will weigh in with my response---I believe that all of the coordinates of the stars, planets, etc. , . . might have the same margins of error--if they do, then it is a systematic error of the software---e.g. the wrong coordinates were originally programmed into the software, software error in computing the coordinates, . . . I doubt if there's a problem with the coordinates or computations: anything that systematically changed the position of the stars would lead to a cluster somewhere in the sky, and problems with rise times, set times and visibility from particular locations.

First thing to do is to be certain that you're actually getting the program to generate the position from Dallas, and not somewhere else. (Sorry, that's the equivalent of "Is it plugged in?" but it has to be mentioned.)
Second thing is to make sure the local time you've given the program is correct, and check that there's an appropriate allowance for daylight saving.
Final thing is to click on Venus in the program, and check the information provided under Altitude and Azimuth. Altitude will tell you the angular distance above the horizon, with zero at the horizon and ninety directly overhead. Then you can compare that figure to the real world.

Grant Hutchison

loglo
2010-Aug-02, 06:00 PM
One other thing to check is to see if you have adjusted correctly for daylight savings time.

grant hutchison
2010-Aug-02, 06:05 PM
One other thing to check is to see if you have adjusted correctly for daylight savings time.Oy. I said that. :)

Grant Hutchison

loglo
2010-Aug-02, 06:06 PM
Sorry I was glossing. :)

John Jaksich
2010-Aug-03, 02:02 PM
Thank you for correcting me ---grant hutchison


The author for Stellarium was recently interviewed on FLOSS-- podcast

Here he is in his own words from his web site: porpoisehead.net





A couple of days ago I was on the TWiT netcast show FLOSS Weekly talking about Stellarium. I was pretty nervous - the show was recorded in front of thousands of live streaming viewers and has a fairly big listenership as a podcast too. Not to mention that previous guests have included some pretty big names in the free / open source world, including Linus Torvalds himself!

I think I managed to babble somewhat coherently for most of the show, although there were a few pretty awkward moments including a total skype fail half way through. :-(

Anyhow, you can download the show here.
By matthew at 2010-02-05 13:14


Maybe someone can locate the podcast---I currently can not!:o

formulaterp
2010-Aug-05, 06:31 AM
Maybe someone can locate the podcast---I currently can not!:o

Here you go:

http://twit.tv/floss107

Daggerstab
2010-Aug-05, 09:30 AM
You might try to e-mail or locate the developer(s) --they are based in France--


The author for Stellarium was recently interviewed on FLOSS-- podcast

Minor correction - like most free/open-source software, Stellarium is developed by a group of contributors from all over the world (including me (https://launchpad.net/~daggerstab)). The original author and current lead developer, Fabien Cheréau, is French. The guy interviewed by the FLOSS Weekly podcast is Matthew Gates, the other project administrator.