Difference between revisions of "Planet"

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This page documents the '''planet''' function of Python module [[Analysis Utilities|analysisUtils]].
 
This page documents the '''planet''' function of Python module [[Analysis Utilities|analysisUtils]].
  
This function returns the apparent position and angular size of any Solar System body for the specified date from the specified observatory.  By default, it contacts the [http://ssd.jpl.nasa.gov/horizons.cgi#top 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.  In case an internet connection is not available, there is an option to instead query
+
This function returns the position (J2000 or apparent) and angular size of any Solar System body for the specified date from the specified observatory (or geocentric).  By default, it contacts the [http://ssd.jpl.nasa.gov/horizons.cgi#top JPL Horizons] telnet server to get apparent angular size, position and rate 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.  In case an internet connection is not available, there is an option to instead query the casa ephemerides (useJPL=False).  However, the reported values will be less accurate due to the need to interpolate from a coarser grid.  Also, using the casa ephemerides presently (casa <= 3.4) returns the apparent position but this will be changed to J2000 in casa 3.5.
the casa ephemerides (useJPL=False).  However, the reported values will be less accurate due to the need to interpolate from
 
a coarser grid.  Also, using the casa ephemerides presently requires the observatory to be ALMA.
 
  
 
==Usage==
 
==Usage==
  
 
au.planet(solarSystemBody="", date="", observatory='ALMA', verbose=False, help=False, beam="",useJPL=True,  
 
au.planet(solarSystemBody="", date="", observatory='ALMA', verbose=False, help=False, beam="",useJPL=True,  
standard='Butler-JPL-Horizons 2010')
+
standard='Butler-JPL-Horizons 2010', apparent=False)
 
   body: string name of Solar system body
 
   body: string name of Solar system body
 
   date: one possible format of the date string is: '2011-10-31 11:59:59'
 
   date: one possible format of the date string is: '2011-10-31 11:59:59'
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     casa tables fail for any reason, it will automatically revert to using
 
     casa tables fail for any reason, it will automatically revert to using
 
     JPL's server.  It may require a few seconds to reach the JPL server.
 
     JPL's server.  It may require a few seconds to reach the JPL server.
   observatory: Observatories can be specifed by JPL ID string, or by the
+
   observatory: Observatories can be specified by JPL ID string, or by the
 
     following names:<br>
 
     following names:<br>
 
   {|
 
   {|
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  |-
 
  |-
 
  | 'OVRO' || (which will be converted to = '-81')  
 
  | 'OVRO' || (which will be converted to = '-81')  
 +
|-
 +
| 'geocentric' || (which will be converted to = '500')
 
   |}
 
   |}
 
   beam:  If a beam size is included (in arcsec), the expected FWHM will be
 
   beam:  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.
 
     computed using scipy.signal.convolve() of a Gaussian with a uniform disk.
 +
  apparent: False = the return values are J2000 as seen from the specified location
 +
  apparent: True = the return values are Apparent as seen from the specified location
  
 
The return values are apparent values as seen from the specified observatory:
 
The return values are apparent values as seen from the specified observatory:

Revision as of 15:25, 20 August 2012

Return to Analysis Utilities

This page documents the planet function of Python module analysisUtils.

This function returns the position (J2000 or apparent) and angular size of any Solar System body for the specified date from the specified observatory (or geocentric). By default, it contacts the JPL Horizons telnet server to get apparent angular size, position and rate 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. In case an internet connection is not available, there is an option to instead query the casa ephemerides (useJPL=False). However, the reported values will be less accurate due to the need to interpolate from a coarser grid. Also, using the casa ephemerides presently (casa <= 3.4) returns the apparent position but this will be changed to J2000 in casa 3.5.

Usage

au.planet(solarSystemBody="", date="", observatory='ALMA', verbose=False, help=False, beam="",useJPL=True, standard='Butler-JPL-Horizons 2010', apparent=False)

 body: string name of Solar system body
 date: one possible format of the date string is: '2011-10-31 11:59:59'
   or simply '2011-10-31' for 0:00 UT. A list of allowed formats for date
   is at:   http://ssd.jpl.nasa.gov/?horizons_doc#time
 useJPL: if False, first try the casa ephemerides.  Note that the casa tables
   are quantized to one day, and can be in error by many arcminutes. If the
   casa tables fail for any reason, it will automatically revert to using
   JPL's server.  It may require a few seconds to reach the JPL server.
 observatory: Observatories can be specified by JPL ID string, 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')
'geocentric' (which will be converted to = '500')
 beam:  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.
 apparent: False = the return values are J2000 as seen from the specified location
 apparent: True = the return values are Apparent as seen from the specified location

The return values are apparent values as seen from the specified observatory: The dictionary returned is:

 data['directionRadians']
 data['angularDiameter'] (in arc seconds)
 data['rateRadiansPerSecond'] (only present if useJPL=True)
 data['rangeRateKms'] (only present if useJPL=True)
 data['rangeAU'] (only present if useJPL=True)

Examples

CASA <3>: au.planet('Titan','2012-04-01','EVLA')
Using observatory: VLA = -5
Contacting JPL Horizons for Titan
Assuming 0 hours UT
MJD= 56018.00000, MJDseconds = 4839955200.0
LST day = 62742,  LST = 5.4757 hours (at longitude=-107.618334)
Julian day = 2456018.500000, MJD = 56018.000000, MJD seconds = 4839955200.000000
Confirmed Observatory name =  VLA
Confirmed Target ID = 606 = Titan
Range rate = -12.386017 km/sec
J2000 Position: 13:44:49.19, -007:52:27.645, rate: -11.9723, 3.3884 arcsec/hr
Angular diameter = 0.811703 arcsec
  Out[3]:
{'angularDiameter': 0.81170299999999995,
 'directionRadians': [3.5989557494879238, -0.13743326065058692],
 'rangeAU': 8.7480170957841707,
 'rangeRateKms': -12.3860165,
 'rateRadiansPerSecond': [-1.6123152317632495e-08, 4.5631673694531841e-09]}

CASA <4>: au.planet('Moon','2012-04-01 12:55')
Contacting JPL Horizons for Moon
MJD= 56018.53819, MJDseconds = 4840001700.0
LST day = 62742,  LST = 21.0853 hours (at longitude=-67.754929)
Julian day = 2456019.038194, MJD = 56018.538194, MJD seconds = 4840001700.000000
Confirmed Observatory name =  ALMA
Confirmed Target ID = 301 = Moon
Range rate = -0.156855 km/sec
J2000 Position: 08:14:33.97, +015:40:16.537, rate: 2648.9190, -473.5570 arcsec/hr
Angular diameter = 1831.355000 arcsec
  Out[4]:
{'angularDiameter': 1831.355,
 'directionRadians': [2.1579522305263157, 0.27351509191740353],
 'rangeAU': 0.0026161249308700001,
 'rangeRateKms': -0.15685499999999999,
 'rateRadiansPerSecond': [3.5673115870860856e-06, -6.3774142329219044e-07]}

CASA <2>: au.planet('Ceres',useJPL=False)
No date/time specified, assuming today=2012-05-08 at UT 0:00
Using casa's ephemerides for Ceres. Note these can be in error by a
few arcminutes.  Set useJPL=True for highest accuracy.
J2000 Position: 02:42:12.97, +010:15:42.228
Angular diameter = 0.342199 arcsec
  Out[2]: 
{'angularDiameter': 0.34219936014504132,
 'directionRadians': [0.70780169751840638, 0.17910097545067771]}