Celestia Forums

http://astroblogger.blogspot.com.au/201 ... g-hit.html

======================2013A1.ssc=============================
"Siding-Spring:C2013 A1" "Sol"
{
#Close approach of this comet to Mars
Class "comet" # Just copying the data for Halley
Mesh "halley.cmod"
Texture "asteroid.jpg"
Radius 3 # best guess at maximum semi-axis
MeshCenter [ -0.338 1.303 0.230 ]


EllipticalOrbit
{
Epoch 2456955.47179 # 2014 25 Oct
Period 217204.51919319 # (q/(1-e))^1.5 hyperbolic orbit
SemiMajorAxis -3613.3711384783 #Hyperbolic orbit
PericenterDistance 1.396000248531628
Eccentricity 1.000467
Inclination 128.9984
AscendingNode 300.9204
ArgOfPericenter 2.4695
#MeanAnomaly 359.9970184682824 #MA messes up hyperbolic orbits
}

# Again, this data is copied straight from the ssc files for Halleys’ Comet
# chaotic rotation, imperfectly defined:
# this version from "The New Solar System", 4th Edition; Eds.
# JK Beatty, CC Petersen, A Chaikin
PrecessingRotation
{
Period 170 # 7.1 day axial rotation period
Inclination 66
PrecessionPeriod 3457004.12 # 3.7 day precession period
}

Albedo 0.8
}
===========================================================

Leonid Elenin has observed this comet, and he have calculated that the comet might pass Mars with 0.000276 AU, 41,300 km,
http://spaceobs.org/en/2013/02/27/new-d ... 1-to-mars/

Have there anytime impacted a comet on Mars before?

http://www.nasa.gov/mission_pages/aster ... 30305.html

This does not work for me

How could I know what goes wrong? I see nothing in the console. It just seems that the file is just ignored (and yes I did put it in the "extras" directory).

Should work!

models and textures are already present in Celestia at the right place. Don't bother with that.

When you copy the text and save it as a ssc file do not include these lines at the beginning and at the end

======================2013A1.ssc=============================

===========================================================

They are not part of the ssc file and cause an error if they are in the file.

jogad wrote:======================2013A1.ssc=============================

===========================================================

They are not part of the ssc file and cause an error if they are in the file.

No, I did not put these lines (I'm not that dumb )

There should really be a debug mode or something so we know what's wrong with ssc files.

Maybe I messed up my installation files or something. I'll try to uninstall and reinstall. Update: Nope, did not work.

azorni wrote:No, I did not put these lines (I'm not that dumb )

Don't be offended.
I made ??the mistake and I thought that someone else could have done it too.

Could you try the attached file that works well for me ?
(it is zipped because files with ssc extension are not allowed as post attachments)

Celestia does provide a console log which includes errors.
Type a ~ (<tilde>) to toggle it on and off. On keyboards which support diacritical marks, you might need to type
<tilde> <spacebar>
Use the arrow keys to navigate in it.

Unless you've made a typo while copying it, there aren't any errors in this SSC file, though, so all you'll see is the notice that the SSC has been loaded.

The problems I'm seeing are that Celestia doesn't draw hyperbolic orbit paths, the comet is tiny, and it's very far out from the Sun right now. As a result, you have to get very close to it to see anything, and its tail is being drawn as extremely faint.

If you want to Celestia to draw a bright comet tail, you can change the comet's Radius value to be much larger. 300 KM makes it easy to see in the fall of 2014.

jogad wrote:Could you try the attached file that works well for me ?
(it is zipped because files with ssc extension are not allowed as post attachments)

Yep, this one works for me as well. Thanks. I don't see the difference with what I tried. It's confusing. Maybe the file encoding?

Update: it does not seem to get very close with this orbit, though. I get only about a third of one AU:

 

azorni wrote:it does not seem to get very close with this orbit, though. I get only about a third of one AU

Yes.

For me it is because SemiMajorAxis is not relevant for hyperbolic orbits.

just comment out the corresponding line like this


(or just delete it)

For those who are new to Celestia's files editing, remember to edit a file with a plain text editor and NOT with a word processor.

with this simple correction I get this:


We find Siding-spring at about 2.75 milions kilometers from Mars.
Note that the radius of the comet is untouched (3 km)

Here s is the cel:url to go there when you have updated the ssc file:
cel://PhaseLock/Sol:Mars/Sol:Siding-Spr ... rc=0&ver=3

lodgy wrote:It's good for me !
BUT :

jogad wrote: We find Siding-spring at about 2.75milions kilometers from Mars

from the link given by symaski62 (Nasa), the comet should pass within 50,000 km of Mars.
with data of jogad, it is more than 2.3 million km on 19th oct 2014 ???
We should review the data ssc, right ?
Is it the same problem that "2012 DA 14" topic ?

You must convert orbital elements to Epoch 2014 10 19 but in Epoch write not that date but perihelium date.

Here my ssc code

http://neo.jpl.nasa.gov/news/news179.html