Comment 11 for bug 1291005

Thank you very much for sharing your observations here which confirm my own
ones. I went another line then to find real positions of Ceres and Vesta,
namely with help of "Kosmos Himmelsjahr 2014" tables. Charts in this book
for amateur
observers are magnifying sky areas not that size than Stellarium does, but
accuracy was
enough to fix their positions (about several weeks ago), only Pallas I was
not real sure
to have identified after having tried to compare Stellarium positions with
real sky (in February).

If you feel that my bug report sounds like a blame to Stellarium program,
so this was never in my mind to do so, really. But I apologize if any user
felt like you did...sorry for that. I only wanted to tell the facts and
searched
for help to being able to correct that bug eventually.

Another user had informed me a couple of weeks ago that orbital elements
of asteroids are outdated in Stellarium as they were created in 2010 epoch,
4 years ago. So disturbing effects have added since then to those two days
of misguiding their positions now (diferring a bit from asteroid to
asteroid of course).

What is the way to give an input for correcting this bug? Who is owning a
complete
list of actual orbital elements of either all wellknown asteroids or at
least the bigger ones
(for example the first 100)?

Very best regards, and thanks a lot for reporting!

Torsten

In a message dated 11.04.2014 00:50:38 Mitteleuropäische Sommerzeit,
<email address hidden> writes:

Can confirm. Vesta and Ceres in Stellarium are about 2 days behind their
position in the sky as I found them last night.

I don't think it is fair to have an emotional response in blaming a
software program for being inaccurate. As with any non-life-critical
software, there is no implied warranty for any particular purpose. I
personally have been consistently pleasantly surprised at how good and
accurate Stellarium has been at simulating the sky, as I tried to not
have a prior expectation of a level of performance. I approached all
prediction results with a degree of skepticism. And everything has been
perfect.

However, the first time I tried I couldn't find Vesta. When I tried a
second night, I carefully star-hopped until I was definitely sure I
found the right spot in the sky and Vesta wasn't there. With some
searching I did find it nearby, a star that shouldn't be there, among
the other stars. Incidentally that was the position where Vesta would be
two days in the future according to Stellarium. By checking its two-day
future location, I found Ceres as well. In a way this has been an
adventure, an opportunity for me personally to recreate the experience
of the original discoverers. I am not emotionally upset at having been
misinformed.

To the extent that dwarf planets are important bright sky objects
though, their inaccurate position is still a bug and should be fixed.
Either by updating the Stellarium distribution with newer orbital data,
or by making the orbital perturbations calculations apply to them as
well.

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https://bugs.launchpad.net/bugs/1291005

Title:
very wrong positions of minor planets

Status in Stellarium:
New

Bug description:
I tried to observe three of the minor planets during last two weeks
(Pallas, Vesta, Ceres) and had problems to find their positions at the
night sky using Stellarium 0.12.4 version. With Pallas and Vesta I
succeeded at last, but not really satisfied when comparing real
constellation with constellation shown in Stellarium. But with Ceres I
failed completely last night. At the position where she should have to
be seen very clearly there was nothing than black space. Comparing
your calculated ephemerides with an annual guide I am using since a
couple of years with great success, I realized that Ceres was shown
at a position at least

5 DAYS TOO LATE !

Similarly did that happen to Pallas and Vesta positions, but they
differred 'only' about two days in movement (too late also), and
Pallas' orbit line is not really what you will observe in the sky, it
moves a bit more to the right (smaller values of rectascension I estimate,
maybe smaller values of declination too).

Of course this experience was some sort of frustrating for me as I trusted
in calculated positions of such well-known objects in the sky even if
Stellarium is an amateur developped program with no cost. Now I am irritated a
bit whether or
not there is to be trusted in the shown positions of other minor objects.

Maybe there is an unsufficient input of data for ephemerides of minor
planets in summary (no disturbing calculation?
wrong equinox or without adjustment to nowadays?). I only can guess, but I
dont know. It would be fine if you find
the reason for this problem and it can be solved.

Thank you for listening to my description!

Best regards,

Torsten Merkel

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