SSO Three-Epoch Ephemerides File (June 16 2010)
[sso03 WSDC D-I147, vsn 1.2]
Interface Name: SSO Three-Epoch Ephemerides
Type of Interface: table file
Written By: SSOID (ssoinit)__________________________ J. Fowler
Read By: Offline Analysis
DESCRIPTION:
The SSO Three-Epoch Ephemerides File contains the spacecraft-centered
positions in J2000 RA and Dec for requested SSOs at each of the three
epochs processed by the SSOID module ssoinit in a single execution. These
three epochs are the first and last frameset times for a scan and the time
of one frameset near the middle of the scan. The objects requested need not
be in the scan swath. Along with RA and Dec, the scan-swath Az and El angles
are also provided. In order to be in the scan swath, an object must have
both AzMin < Az < AzMax and ElMin < El < ElMax. The limits are conservative
in order to avoid failing to predict an object, so typically an object must
be at least a degree inside the window to be in any frame of the scan.
This product is requested by specifying a list of SSO names and an output
file name via the "-i2" and "-o2" command-line options, respectively. The
"-i2" flag specifies an ASCII text file containing enough of an SSO name to
be unique, one per line, starting in column one. An example is:
Ceres
Neptune
Earth
White-Ortiz-Bolelli 1970 K1
When ssoinit encounters an object whose name was given in this file, it
writes the positions at the three epochs to the output table file.
Table Header Information:
Epoch1: Epoch of first frameset in scan, JD
Epoch2: Epoch of second frameset in scan, JD
Epoch3: Epoch of third frameset in scan, JD
AzMin: Minimum Az angle, deg
AzMax: Maximum Az angle, deg
ElMin: Minimum El angle, deg
ElMax: Maximum El angle, deg
Description of Columns:
Cols Name Description Units Type Format
------- ------ ------------------------------------- ------- ---- --------
1-36 NAME Standard object ID field [1] - C*35 1x,A35
37-38 N Epoch number, 1, 2, or 3 - I*4 I2
39-50 RA RA deg R*8 F12.6
51-61 Dec Dec deg R*8 F11.6
62-72 Az Azimuth in scan coordinates [2] deg R*8 F11.6
73-83 El Elevation in scan coordinates [2] deg R*8 F11.6
Notes:
1.) The NAME field may contain any combination of MPC number, object name (e.g.,
Ceres), and (provisional-)designation; comets and planets have no MPC
numbers.
2.) The scan coordinate system is a spherical coordinate system with the scan
axis as its pole and the zero of azimuth at the center of the first
frameset; see section 3.1 of the SSOID SDS, WSDC D-D017.
EXAMPLE:
\ Generated by ssoinit vsn 1.2 A90401
\Epoch1 = 2455212.787627
\Epoch2 = 2455212.803796
\Epoch3 = 2455212.819965
\AzMin = -2.096039
\AzMax = 192.049272
\ElMin = -2.096039
\ElMax = 2.096039
| Name |N| RA | Dec | Az | El |
| char |i| real | real | real | real |
(G1247) 2003 BM84 1 109.258018 27.260358 172.248978 -84.898274
(G1247) 2003 BM84 2 109.255207 27.258959 172.219037 -84.899395
(G1247) 2003 BM84 3 109.247349 27.258063 172.139091 -84.899523
2009 BM84 1 195.386020 -15.008762 283.825430 1.613753
2009 BM84 2 195.388318 -15.011211 283.826838 1.616742
2009 BM84 3 195.390701 -15.013999 283.828528 1.619936
2004 BM84 1 308.100075 -9.839457 120.679756 68.588627
2004 BM84 2 308.105804 -9.838780 120.671816 68.583733
2004 BM84 3 308.112925 -9.837885 120.662071 68.577615