Stellarium freezes on near-parabolic comets

[Alexander Wolf]

Original bug report in Debian bug tracker: https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=788699

Our old bug report: https://bugs.launchpad.net/stellarium/+bug/1030913

Apparently we should improve calculation of orbits for near-parabolic and parabolic comets.

[gzotti (georg-zotti)]

Bad news!

I had hoped the new algorithm was stable enough and fixed the 2012 issue. The analysis in the Debian report is excellent. But I'd like to know which orbital elements cause this.

Guess I shall have a look a this...

[Alexander Wolf (alexwolf)]

From Debian bug report:

Hi again,

Btw, the object causing the trouble is .... wait for it ... C/2014 OE4!
(see orbit_Eccentricity=0.999993 in ssystem.ini). Actually, it
seems that the eccentricity is smaller [1], but the case remains.

There are other objects with high e's which may cause trouble as well
(look for "Eccentricity=0.9999" in ssystem.ini). And there are objects
with e's close to 1 from above (search for "Eccentricity=1.0000")
which *could* be problematic.

Tomasz

[1] http://www.aerith.net/comet/catalog/2014OE4/2014OE4.html

[Alexander Wolf (alexwolf)]

I think we can use idea from [1] and implement the persistent resolution of the issue.

[1] https://anonscm.debian.org/cgit/users/tomasz/orbits.git

[gzotti (georg-zotti)]

r7903 provides a fix. Thanks Thomas Buchert and Paweł T. Jochym for identifying this one.