Quote:
Originally Posted by CometGuy
Not sure if this link will help, but has updated orbital elements for different programs:
http://www.minorplanetcenter.org/iau...ftwareEls.html
As for the JPL orbit it appears to be similiar to the original orbit published in MPEC 2010-X101 on December 12. However, the latest orbit on MPEC 2010-Y24 is based on 12 days of observation. I believe the perihelion distance and general orbit is pretty close to correct in Y24, however I believe the Perihelion date may change a couple of days.
For stellarium it seems that
q = orbit_PericenterDistance
T = orbit_TimeAtPericenter (but you have to convert to Julian Date). |
Stellarium 0.10.6.1 can use the MPC data directly with the "Solar System Editor" plugin - you only have to enable it, restart and run through the panels to import the data.
The way Stellarium uses the radius and albedo to calculate the size and brightness leads me to suggest these with Terry's figures:
Code:
radius = 86.1944596468567
albedo = 0.15
except in 0.10.6 and beyond which allows for H and G to be retained and so:
Code:
radius = 5 # fictitious as documented in the source code
albedo = 1 # also fictitious
absolute_magnitude = 8
slope_parameter = 4
However an albedo of 0.15 is supposed to be a reasonable average value for comets, and give that the formula (Perl syntax):
Code:
$radius=1329/sqrt($albedo)*10**(-0.2*$mag);
is accepted as valid by several references, the radius comes out at around 86.
Barry, if you see this, can you get that formula given some consideration instead of the hard coded values in the source? The same formula applies to asteroids using albedo 0.04