Planet

From CASA Guides
Revision as of 14:28, 16 March 2012 by Thunter (talk | contribs) (→‎Usage)
Jump to navigationJump to search

Return to Analysis Utilities

This page documents the planet function of Python module analysisUtils.

This function contacts the JPL Horizons telnet server to get apparent angular size, position and rate (in the J2000 reference frame) of any Solar System body. If the date and time is not specified, today's date is assumed at 0:00 UT. If the time is not specified, 0:00 UT is assumed. If the observatory is not specified, ALMA is assumed. It returns a dictionary of: {'directionRadians', 'rateRadiansPerSecond', 'angularDiameter'} where the first two elements are a list two values in radians: RA, Dec, and the third element is a scalar float in arc seconds, or [] if the information is not available.


Usage

Usage: au.planet(solarSystemBody="", date="", observatory='ALMA', verbose=False, help=False, beam=)
One possible format of the date string is: '2011-10-31 11:59:59' or simply '2011-10-31' for 0 UT
A complete list of allowed formats for date is at: http://ssd.jpl.nasa.gov/?horizons_doc#time
Observatories can be specified by JPL ID string, JPL ID integer, or by the following names:

 * 'VLA' (which will be converted to = '-5')
 * 'ALMA' (which will be converted to = '-7')
 * 'GBT' (which will be converted to = '-9')
 * 'MAUNAKEA' (which will be converted to = '-80')
 * 'OVRO' (which will be converted to = '-81')

If a beam size is included (in arcsec), the expected FWHM will be computed using scipy.signal.convolve() of a Gaussian with a uniform disk.

Examples

CASA <7>: au.planet('Titan','2012-04-01','EVLA')
Using observatory: VLA = -5
Assuming 0 hours UT
MJD= 56018.00000, MJDseconds = 4839955200.0
Confirmed Observatory name =  VLA
Confirmed Target ID = 606 = Titan
J2000 Position: 13:44:49.19, -007:52:27.645, rate: -11.9723, 3.3884 arcsec/hr
Angular diameter = 0.811703 arcsec
  Out[7]:
{'angularDiameter': 0.81170299999999995,
 'directionRadians': [3.5989557494879238, -0.13743326065058692],
 'rateRadiansPerSecond': [-1.6123152317632495e-08, 4.5631673694531841e-09]}

CASA <10>: au.planet('Moon','2012-04-01 12:55')
MJD= 56018.53819, MJDseconds = 4840001700.0
Confirmed Observatory name =  ALMA
Confirmed Target ID = 301 = Moon
J2000 Position: 08:14:33.97, +015:40:16.537, rate: 2648.9190, -473.5570 arcsec/hr
Angular diameter = 1831.355000 arcsec
  Out[10]:
{'angularDiameter': 1831.355,
 'directionRadians': [2.1579522287809869, 0.27351509191740353],
 'rateRadiansPerSecond': [3.5673115870860856e-06, -6.3774142329219044e-07]}