2.3.2
spase://NASA/NumericalData/Planet/Saturn/HelioWeb/Ephemeris/P1D
Saturn Ephemeris, Heliocentric Trajectories, Heliographic, Heliographic Inertial, and Solar Ecliptic Coordinates, HelioWeb, Daily Data
2021-04-27T15:38:11Z
Heliocentric trajectories for Planet Saturn in Heliographic, HG, Heliographic Inertial, HGI, and Solar Ecliptic, SE, Coordinates
The original trajectory data are taken from http://ssd.jpl.nasa.gov/horizons.cgi where users can find many more objects. In the case of orbit data for planets, the orbit data can be used as a proxy for spacecraft ephemeris that are in orbit about the planets. On a heliospheric scale, differences between the planet orbital tarjectory and that of the spacecraft are very small. For instance, the heliocentric longitudes differ by only 0.25° for a spacecraft stationed near the L1 Lagrange point at approximately 100 Earth radii upstream of the Earth.
The production of the HG, HGI, and SE trajectory data requires a values for the "Equinox Epoch", which is defined as the epoch time when the direction from the Earth to the sun at the time of the vernal equinox when the sun seems to cross equatorial plane of the Earth from below. This direction is called the First Point of Aries, FPA and it is not a fixed direction but drifts by about 1.4° per century or 50.26" per year. In addition, there are tiny irregularities in FPA drift that are on the order of 1" per year or less. The Equinox Epoch can be determined by using a variety of methods for calculating the instantaneous FPA longitudinal direction and whether the tiny irregularities have been smoothed or averaged out. Four methods for determining the Equinox Epoch are in common usage:
+---------------------------------------------------------------------+
| Method Name | FPA Longitude Definition |
|---------------------------------------------------------------------|
| B1950.0 | the actual FPA at 22:09 UT on December 31, 1949 |
| J2000.0 | the smoothed FPA at 12:00 UT on January 1, 2000 |
| True of Date | the actual FPA at 00:00 UT on the date of interest |
| Mean of Date | the smoothed FPA at 00:00 UT on the date of interest |
+---------------------------------------------------------------------+
The heliocentric trajectory data included in this data product have been calculated by using the Equinox Epoch: defined via the "Mean of Date" method.
More precise coordinates, and some planet-centered coordinates, are found in the "traj" subdirectories of spacecraft specific directories at https://spdf.gsfc.nasa.gov/pub/data/ and http://ssd.jpl.nasa.gov/horizons.cgi.
Please acknowledge N.E. Papitashvili for use of the Data
spase://SMWG/Person/Natalia.E.Papitashvili
GeneralContact
spase://SMWG/Person/Robert.M.Candey
MetadataContact
spase://SMWG/Person/Lee.Frost.Bargatze
MetadataContact
Heliocentric Trajectories HelioWeb Data Service, NASA GSFC
https://omniweb.gsfc.nasa.gov/coho/helios/heli.html
Heliocentric trajectories for selected spacecraft, planets, and comets, HelioWeb data service, hosted by NASA GSFC
Heliocentric Trajectories HelioWeb Data Service Usage Instructions, NASA GSFC
https://omniweb.gsfc.nasa.gov/coho/helios/about_helioweb.html
Instructions for using the Heliocentric Trajectories HelioWeb data service, hosted by NASA GSFC
Heliocentric Trajectories HelioWeb Data Service Usage via CURL or WGET Commands, NASA GSFC
https://omniweb.gsfc.nasa.gov/coho/helios/helioweb_command_line_sample.txt
Instructions for using the Heliocentric Trajectories HelioWeb data service via CURL or WGET commands, hosted by NASA GSFC
HG, HGI, and SE Coordinate System Definitions, NASA GSFC
https://omniweb.gsfc.nasa.gov/coho/helios/coor_des.html
Definitions for the Heliographic, HG, Heliographic Inertial, HGI, and Solar Ecliptic, SE, Coordinate Systems, hosted by NASA GSFC
Satellite Situation Center (SSCWeb) System and Services, NASA GSFC
https://sscweb.gsfc.nasa.gov
Satellite Situation Center (SSCWeb) web page offering a variety of services that provide access to orbit trajectory graphics and listings, hosted by NASA GSFC
HORIZONS Web Interface, NASA JPL
https://ssd.jpl.nasa.gov/horizons.cgi
HORIZONS Web Interface, a web page that provides limited access to the JPL HORIZONS system which can be used to generate ephemerides for solar system bodies
spase://VSPO/NumericalData/Planet/Saturn/HelioWeb/Ephemeris/P1D
spase://SMWG/Repository/NASA/GSFC/SPDF
Online
Open
FTPS from SPDF (not with most browsers)
ftps://spdf.gsfc.nasa.gov/pub/data/planet_and_comet_positions/helio1day/
Access to Data in CDF Format via ftp from SPDF
HTTPS from SPDF
https://spdf.gsfc.nasa.gov/pub/data/planet_and_comet_positions/helio1day/
Access to Data in CDF Format via http from SPDF
CDAWeb
https://cdaweb.gsfc.nasa.gov/cgi-bin/eval2.cgi?dataset=SATURN_HELIO1DAY_POSITION&index=sp_phys
SATURN_HELIO1DAY_POSITION
Access to ASCII, CDF, and Plots via NASA/GSFC CDAWeb
CDF
None
Please acknowledge N.E. Papitashvili. Please acknowledge the Data Providers and CDAWeb when using these Data.
spase://SMWG/Repository/NASA/GSFC/SPDF
Online
Open
CDAWeb HAPI Server
https://cdaweb.gsfc.nasa.gov/hapi
SATURN_HELIO1DAY_POSITION
Web Service to this product using the HAPI interface.
CSV
Please acknowledge N.E. Papitashvili. Please acknowledge the Data Providers and CDAWeb when using these Data.
Calibrated
Ephemeris
1965-01-01T00:00:00.000
2020-12-31T00:00:00.000
P1D
Epoch Time
Epoch
Epoch Time, beginning of interval
This Parameter exhibits an increasing Monotonic Progression
P1D
ms
1.0e-3>s
Epoch
E14.8
6.2987652219904e+13
6.3745034619904e+13
LinearScale
01-Jan-1996 00:00:00.000
01-Jan-2020 00:00:00.000
31-Dec-9999 23:59:59.999
Temporal
Saturn Position, Heliocentric Radial Distance
Time Series defined by using: EPOCH
RAD_AU
Saturn Position, Heliocentric Radial Distance
P1D
ua
1.495978706961e11>m
TimeSeries
RAD_AU
F8.2
0.0
1000.0
-1.0e+31
Temporal
Saturn Position, Latitude, Solar Ecliptic Coordinates
Time Series defined by using: EPOCH
SE_LAT
Saturn Position, Latitude, Solar Ecliptic, SE, Spherical Coordinates
P1D
°
0.0174532925>rad
Spherical
SE
TimeSeries
SE_LAT
F8.1
-90.0
90.0
-1.0e+31
DirectionAngle.ElevationAngle
Scalar
Positional
Saturn Position, Longitude, Solar Ecliptic Coordinates
Time Series defined by using: EPOCH
SE_LON
Saturn Position, Longitude, Solar Ecliptic, SE, Spherical Coordinates
P1D
°
0.0174532925>rad
Spherical
SE
TimeSeries
SE_LON
F8.1
0.0
360.0
-1.0e+31
DirectionAngle.AzimuthAngle
Scalar
Positional
Saturn Position, Latitude, Heliographic Coordinates
Time Series defined by using: EPOCH
HG_LAT
Saturn Position, Latitude, Heliographic, HG, Spherical Coordinates
P1D
°
0.0174532925>rad
Spherical
HG
TimeSeries
HG_LAT
F8.1
-90.0
90.0
-1.0e+31
DirectionAngle.ElevationAngle
Scalar
Positional
Saturn Position, Longitude, Heliographic Coordinates
Time Series defined by using: EPOCH
HG_LON
Saturn Position, Longitude, Heliographic, HG, Spherical Coordinates
P1D
°
0.0174532925>rad
Spherical
HG
TimeSeries
HG_LON
F8.1
0.0
360.0
-1.0e+31
DirectionAngle.AzimuthAngle
Scalar
Positional
Saturn Position, Latitude, Heliographic Inertial Coordinates
Time Series defined by using: EPOCH
HGI_LAT
Saturn Position, Latitude, Heliographic Inertial, HGI, Spherical Coordinates
P1D
°
0.0174532925>rad
Spherical
HGI
TimeSeries
HGI_LAT
F8.1
-90.0
90.0
-1.0e+31
DirectionAngle.ElevationAngle
Scalar
Positional
Saturn Position, Longitude, Heliographic Inertial Coordinates
Time Series defined by using: EPOCH
HGI_LON
Saturn Position, Longitude, Heliographic Inertial, HGI, Spherical Coordinates
P1D
°
0.0174532925>rad
Spherical
HGI
TimeSeries
HGI_LON
F8.1
0.0
360.0
-1.0e+31
DirectionAngle.AzimuthAngle
Scalar
Positional