Using Stellarium to track asteroids

[Imd]

Hi,

I'm a little stuck with Stellarium.

I was wondering if anyone has successfully used Stellarium to track 2012 DA14 or any other asteroid. I was hoping to use this to help track the asteroid as it flies by but my efforts seem to be giving inaccurate results when compared with http://www.britastro.org/~rmiles/Images/2012DA14_UKchart_2100-0100UT.png. I'm wondering if its because my location is different.

To collect the orbital data I used

http://ssd.jpl.nasa.gov/horizons.cgi?find_body=1&body_group=sb&sstr=2012 DA14

and the used to parse the data into a formart for Stellarium:

http://projects.familie-steinel.de/stellarium-comet-jpl/

then inserted the following data in Ssystem.ini used by stellarium. (I am based in Solihull, UK), Please could any of you help me by pointing the error of my ways?

[Asteroid 2012 DA14]

# Data taken from JPL/HORIZONS

# correct for the specified time frame:

# Start Time : 1.044270372779227E+01

# Stop Time : 1.044270372779227E+01

name = Asteroid 2012 DA14

parent = Sun

coord_func = comet_orbit

radius = 10

oblateness = 0.0

albedo = 1

lighting = true

halo = true

color = 1.0,1.0,1.0

tex_halo = star16x16.png

tex_map = nomap.png

orbit_Epoch = 2456337.500000000

orbit_TimeAtPericenter = 2456261.698771364

orbit_PericenterDistance = 0.8930153601275327

orbit_Eccentricity = 0.1092592113644565

orbit_ArgOfPericenter = 271.2561444841019

orbit_AscendingNode = 147.1835245278439

orbit_Inclination = 10.44270372779227

Many Thanks

Ian

[Chris Rowland]

I found this with CdC. The problem is that the planetarium programs assume a two body solution for the asteroid position - that it's only affected by the Sun's gravity. This isn't the case for 2012 DA14, the Earth has a huge effect. The answer is to use an ephemeris generated by something such as JPL/Horizons and plot the positions that it gives. It uses a more accurate multi body solution to get better positions.

Chris

[damnut]

Hi Ian,

I'll have a look tomorrow. Below is script that i wrote for two comets, so you are on the right track!!

Cheers

[iSON]

name = C/2012 s1

parent = Sun

radius = 80

oblateness = 0.0

halo = true

color = 1.0,1.0,1.0

tex_halo = star16x16.png

tex_map = nomap.png

coord_func = comet_orbit

orbit_TimeAtPericenter = 2456625.369621431330

orbit_PericenterDistance = .01250446176504045

orbit_Eccentricity = 1.000000000000218

orbit_ArgOfPericenter = 345.50712732

orbit_AscendingNode = 295.7451926842039

orbit_Inclination = 61.81287790235313

lighting = false

albedo = 1

orbit_visualization_period = 365.25

[PANSTARRS]

name = C/2012 L1 (PANSTARRS)

parent = Sun

radius = 10

oblateness = 0.0

halo = true

color = 1.0,1.0,1.0

tex_halo = star16x16.png

tex_map = nomap.png

coord_func = comet_orbit

orbit_TimeAtPericenter = 2456329.3937

orbit_PericenterDistance = .337628

orbit_Eccentricity = 1.0

orbit_ArgOfPericenter = 331.2931

orbit_AscendingNode = 67.5247

orbit_Inclination = 59.95487

lighting = false

albedo = 1

orbit_visualization_period = 365.25

[Imd]

I found this with CdC. The problem is that the planetarium programs assume a two body solution for the asteroid position - that it's only affected by the Sun's gravity. This isn't the case for 2012 DA14, the Earth has a huge effect. The answer is to use an ephemeris generated by something such as JPL/Horizons and plot the positions that it gives. It uses a more accurate multi body solution to get better positions.

Chris

[Imd]

Thanks both for your replies. I wonder if you are right and earths gravity is skewing the results. However, the data was obtained from jpl horizons, parsed the inserted into stellarium.

This is just a test really, my intention is to do the same for panstarrs and ison too. I'm keen to know whether you followed the same process as I did Damnut

[Chris Rowland]

These orbit elements are a description of the ellipse the object would do if the only object was the Sun. It's defined for one time. The effect of the Earth's gravity is to change the orbit elements so they will change as the asteroid passes the Earth.

The Ephemeris (list of positions) that JPL/Horizons generates uses a different method - a numerical integration - that allows for the effect of the gravity of all the solar system objects of any size, this should be more accurate but it will still be worth picking up a new ephemeris close to the time.

Chris

[Imd]

Thanks Chris,

I sounds as though 2012 DA14 is an unusual object which is particularly affected by Earth's gravity and normally the process I used would be more accurate eg ISON, Panstarrs.

I hope that http://www.britastro...2100-0100UT.png. is more inaccurate otherwise may yet get an even colder winter on the way

I will try again on the day and then hopefully I may get a better look at the object at higher magnification.

Ian