very wrong positions of minor planets

[Torsten Merkel]

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

[Alexander Wolf (alexwolf)]

Is it a clean installation of Stellarium? Have you enable the correction of light speed? Which coordinates of minor planets you checked? Which location you has as your place?

[Torsten Merkel (tomerkel)]

Hi,

what do you mean with "clean installation"? I downloaded it from
CHIP ONLINE source, regularly a very trustfully source without viruses or
similar.

Correction of light speed is only important when working with moons of
planets for example or eclipsing events with sun or moon. Time delay is only
about 15 minutes regarding temporary distances of those three minor planets,
so it is nearly no difference in position with or without correction of
light speed, comparing with an observed real difference of about 2-5 days.

I checked no absolute coordinates, only relative positions against star
constellation when
comparing it with printed ephemeride lines in "Kosmos Himmelsjahr 2014"
from Hans-Ulrich Keller,
pages 66 and 108 (look at attachments).

Ceres STELLARIUM position is about 5 days to the left side of dotted line.
The small circles with figures 2,3,4 mean 01.02.2014 / 01.03.2014 /
01.04.2014 respectively , each at 00:00 UT / 01:00 MEZ.
Vesta / Pallas STELLARIUM positions are about 2 days to the left of those
dotted lines.
Pallas Stellarium orbit line moves a bit to the right of dotted line in the
 picture, estimated half of a degree
(30 minutes). Vesta /Ceres orbit lines' position I did not check until
now...maybe they are wrong a bit too.

I am living in Germany near Stuttgart, N 48.45 E 09.15 about.

Hope this helps?

Best regards,

Torsten

In a message dated 11.03.2014 20:35:32 Mitteleuropäische Zeit,
<email address hidden> writes:

Is it a clean installation of Stellarium? Have you enable the
correction of light speed? Which coordinates of minor planets you
checked? Which location you has as your place?

--
You received this bug notification because you are subscribed to the bug
report.
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...

[Torsten Merkel (tomerkel)]

Sorry, I forgot the picture attachments!

Hi,

what do you mean with "clean installation"? I downloaded it from
CHIP ONLINE source, regularly a very trustfully source without viruses or
similar.

Correction of light speed is only important when working with moons of
planets for example or eclipsing events with sun or moon. Time delay is only
about 15 minutes regarding temporary distances of those three minor planets,
so it is nearly no difference in position with or without correction of
light speed, comparing with an observed real difference of about 2-5 days.

I checked no absolute coordinates, only relative positions against star
constellation when
comparing it with printed ephemeride lines in "Kosmos Himmelsjahr 2014"
from Hans-Ulrich Keller,
pages 66 and 108 (look at attachments).

Ceres STELLARIUM position is about 5 days to the left side of dotted line.
The small circles with figures 2,3,4 mean 01.02.2014 / 01.03.2014 / 01.
04.2014 respectively , each at 00:00 UT / 01:00 MEZ.
Vesta / Pallas STELLARIUM positions are about 2 days to the left of those
dotted lines.
Pallas Stellarium orbit line moves a bit to the right of dotted line in the
 picture, estimated half of a degree
(30 minutes). Vesta /Ceres orbit lines' position I did not check until
now...maybe they are wrong a bit too.

I am living in Germany near Stuttgart, N 48.45 E 09.15 about.

Hope this helps?

Best regards,

Torsten

In a message dated 11.03.2014 20:35:32 Mitteleuropäische Zeit,
<email address hidden> writes:

Is it a clean installation of Stellarium? Have you enable the
correction of light speed? Which coordinates of minor planets you
checked? Which location you has as your place?

--
You received this bug notification because you are subscribed to the bug
report.
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 i...

[Torsten Merkel (tomerkel)]

Hi,

now I compared official data for RA/DE from Ceres,Vesta,Pallas with those
given from Stellarium 0.12.4 for 2014/03/31 0:00 UT:

Official release (Kosmos guide) ------------------ Stellarium data
----------------------------------------------------------------------------
------------------------------
                RA DE RA
            DE
----------------------------------------------------------------------------
--------------------------------

Ceres: 14h05m +2.6° 14h09m45s
+2.05°

Vesta: 13h56m +1.6° 13h58m
+1.35"

Pallas: 9h35m +3.5" 9h33m30s
 +3.31°

----------------------------------------------------------------------------
--------------------------------

This means the following deviation values from real positions in absolute
distance:

Ceres: 1.23 degrees (nearly three times the diameter of distant moon
disc!!!)

Vesta: 0.56 degrees (a bit more than diameter of nearest moon disc)

Pallas: 0.45 degrees (a bit less than diameter of distant moon disc).

----------------------------------------------------------------------------
-----------------------------------

These are indeed HEAVY deviations from real values - where do they come
from?

Hope community will find the reason for these bugs....thank you.

best regards,

Torsten

In a message dated 11.03.2014 20:35:32 Mitteleuropäische Zeit,
<email address hidden> writes:

Is it a clean installation of Stellarium? Have you enable the
correction of light speed? Which coordinates of minor planets you
checked? Which location you has as your place?

--
You received this bug notification because you are subscribed to the bug
report.
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 ...

[gzotti (georg-zotti)]

what about comparing orbital elements? They are only valid for a rather short time. Look into ssystem.ini.
G.

[Alexander Wolf (alexwolf)]

>Correction of light speed is only important when working with moons of planets for example or eclipsing events with sun or moon.

What? Correction of light speed is important for ALL events in Solar System.

[Worachate Boonplod (worachateb)]

The orbit of asteroids are outdated (they're from 2010). Planetary perturbation affects their orbits. You need to download new set of them or edit the file ssystem.ini

see
https://bugs.launchpad.net/stellarium/+bug/1288999

[Torsten Merkel (tomerkel)]

may have been misunderstood, what I wanted to say therewith.
Regarding a big failure of 5 days there is a light speed error of 15
minutes
of nearly no influence to this special situation.

By the way: I got helpful answer meanwhile as orbit data for asteroids are
from year
2010 and outdated now. There seems to be no algorithm which calculates
disturbing
influences from major planets, so positions get out of place the longer
time passes.
And I agree that this really is the reason for wrong positions.

Thanks for trying to help!

best regards,

Torsten

In a message dated 12.03.2014 03:45:44 Mitteleuropäische Zeit,
<email address hidden> writes:

>Correction of light speed is only important when working with moons of
planets for example or eclipsing events with sun or moon.

What? Correction of light speed is important for ALL events in Solar
System.

--
You received this bug notification because you are subscribed to the bug
report.
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

To manage notifications about this bug go to:
https://bugs.launchpad.net/stellarium/+bug/1291005/+subscriptions

[Torsten Merkel (tomerkel)]

Thanks for revealing this problem.
Of course that seems to be the reason for wrong positions up to more
than 1 degree now after 4 years of uncorrected orbit values.

By the way: This fact sounds a bit strange to me, as Ceres, Pallas, Juno,
Vesta
are the first four "minor planets" discovered between 1801 and 1807.
They are easily observable from time to time with magnitudes up to 5.5mag.
So I would have expected that at least these four should have been included
 into the
list of perturbation calculation like major planets did for sure. Why NOT?

Thanks a lot for helping with your information!

best regards,

Torsten

In a message dated 12.03.2014 06:15:42 Mitteleuropäische Zeit,
<email address hidden> writes:

The orbit of asteroids are outdated (they're from 2010). Planetary
perturbation affects their orbits. You need to download new set of them
or edit the file ssystem.ini

see
https://bugs.launchpad.net/stellarium/+bug/1288999

--
You received this bug notification because you are subscribed to the bug
report.
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

To manage notifications about this bug go to:
https://bugs.launchpad.net/stellarium/+bug/1291005/+subscriptions

[epstein84 (ebvp44v+i4octc)]

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.

[Torsten Merkel (tomerkel)]

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.

--
You received this bug notification because you are subscribed to the bug
report.
https://bugs.la...

[Alexander Wolf (alexwolf)]

You can use Solar System Editor plugin for updating orbital elements of asteroids and comets (and adding or removing their data).

[gzotti (georg-zotti)]

This is not a bug at all. Osculating orbital elements for minor planets are valid for a rather short time only, as every observer should know. This is the reason for having a feature (the solar system editor plugin) to update orbital elements, just like many other desktop planetaria have this feature. I am not aware of analytic models for orbits of asteroids similar to VSOP87, if somebody can provide it, we may consider adding it.

The online resources usually give "current" elements for observing here and now. I give the question back: Where could we download past elements? How could we date historical photographs of asteroids with software if we don't have historical elements?

The only thing we can change may be providing current elements with every new release. This should go into the release checklist.

[Alexander Wolf (alexwolf)]

The bug report was moved to https://github.com/Stellarium/stellarium/issues/453