Comment 8 for bug 1405460

It's a pity that the bug report was just deleted

It is definitely NOT a duplicated bug as it describes not a position error,
but the bug of filtering, so actual object is not drawn at all. The
position is correct.

I understand the meaning of the line 463, but I prefer slow drawing instead
of no drawing at all.
But practically I played with hundreds of objects with no visible
performance degradation. Now I need just a few comets,
Especially C/2014 Q2 and 15P/Finlay, the brightest ones on the sky. But I
do not see them both due to the above mentioned line 463.

I and not the only person who meets that problem, so wrote about the
temporary solution.

The filtering rule definitely must be changed.

2014-12-25 12:19 GMT+02:00 gzotti <email address hidden>:

> *** This bug is a duplicate of bug 1358230 ***
> https://bugs.launchpad.net/bugs/1358230
>
> I think Alexander is right. I imported the elements from MPC list
> import, not the online search. Comet element sets should NOT have
> orbit_MeanAnomaly or orbit_MeanMotion entries, these don't make much
> sense for most comets!
>
> So this is a duplicate of the bug which Alexander mentioned above. Do
> NOT comment away the test in line 463, or you risk a massive slowdown if
> you have many element sets.
>
> These would be the elements if imported via list import, and these work:
>
>
> [c2014q2%28lovejoy%29]
> orbit_Inclination=80.3027
> slope_parameter=8.4
> coord_func=comet_orbit
> parent=Sun
> orbit_ArgOfPericenter=12.3949
> orbit_PericenterDistance=1.290357
> lighting=false
> radius=5
> type=comet
> dust_brightnessfactor=1.5
> absolute_magnitude=4
> name=C/2014 Q2 (Lovejoy)
> orbit_Eccentricity=0.997796
> orbit_good=267
> orbit_TimeAtPericenter=2457052.56909722
> albedo=0.1
> orbit_AscendingNode=94.9755
> color=1.0, 1.0, 1.0
> dust_lengthfactor=0.4
> dust_widthfactor=1.5
> tex_map=nomap.png
>
>
> [15pfinlay]
> type = comet
> radius = 5
> orbit_good = 176
> absolute_magnitude = 12
> dust_brightnessfactor = 1.5
> name = 15P/Finlay
> orbit_Inclination = 6.799
> dust_lengthfactor = 0.4
> coord_func = comet_orbit
> orbit_ArgOfPericenter = 347.5531
> orbit_PericenterDistance = 0.975903
> albedo = 0.1
> orbit_TimeAtPericenter = 2457018.55689815
> dust_widthfactor = 1.5
> lighting = false
> orbit_AscendingNode = 13.7777
> tex_map = nomap.png
> color = 1.0, 1.0, 1.0
> slope_parameter = 4
> parent = Sun
> orbit_Eccentricity = 0.720178
>
>
> ** This bug has been marked a duplicate of bug 1358230
> Wrong import of comet data by ssystem editor
>
> --
> You received this bug notification because you are subscribed to the bug
> report.
> https://bugs.launchpad.net/bugs/1405460
>
> Title:
> Comet C/2014 Q2 is not visible
>
> Status in Stellarium:
> Incomplete
>
> Bug description:
> After importing comet from MPC, it's position can be found with F3,
> but no actual object is shown.
>
> Drawing is canceled in the following line :
> if (!orbit->objectDateValid(core->getJDay())) return; // don't
> draw at all if out of useful date range. This allows having hundreds of
> comet elements.
> [comet.cpp, line 463]
>
> Further investigations tell us that time_at_pericenter for this object
> has negative value.
>
> The comet is added to the ssystem.ini as usual:
>
> [c2014q2(lovejoy)]
> orbit_SemiMajorAxis = 582.1349
> orbit_ArgOfPericenter = 12.3952
> orbit_Epoch = 2457000.5
> slope_parameter = 8.4
> orbit_AscendingNode = 94.9754
> type = comet
> orbit_MeanAnomaly = 359.9963
> name = C/2014 Q2 (Lovejoy)
> albedo = 0.04
> orbit_MeanMotion = 7.02e-05
> orbit_Eccentricity = 0.997783
> tex_map = nomap.png
> color = 1.0, 1.0, 1.0
> absolute_magnitude = 4
> orbit_Inclination = 80.3029
> parent = Sun
> lighting = false
> coord_func = comet_orbit
> radius = 5
>
>
> There are two possible temporary solutions:
> - add the following line:
> orbit_good=100000000000
>
> - replace
> type = comet
> with
> type = asteroid
>
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>