Celestrak Earth Orientation Parameters File

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The Celestrak Earth Orientation Parameters (earth_orientation_parameters_celestrak.csv) file contains the parameters for polar motion and non-uniform Earth rotation (variation in sidereal time). The file contains correction angles for polar motion (also called polar motion) and values for UT1 and UTC time differences. The data is based on definitive and predicted data as published on Celestrak.

 

This file is updated daily and hosted by Celestrak at: http://celestrak.org/SpaceData/.

 

Note: In addition to the CSV format, FreeFlyer also supports the legacy fixed-field format.

 

Celestrak Earth Orientation Parameters Format

The Celestrak Earth Orientation Parameters (CSV formatted) file contains the following data in columns from left to right:

 

Field

Description

DATE

UTC Year-Month-Day (ISO 8061)

MJD

Modified Julian Date (Julian Date at 0h UTC minus 2400000.5)

X

x (arc seconds)

Y

y (arc seconds)

UT1-UTC

UT1-UTC (seconds)

LOD

Length of Day (seconds)

DPSI

δΔψ (arc seconds)

DEPS

δΔε (arc seconds)

DX

δX (arc seconds)

DY

δY (arc seconds)

DAT

Delta Atomic Time, TAI-UTC (seconds)

DATA_TYPE

O = Observed, P = Predicted

 

An excerpt of the file is given below:
 

12/25/2023        60303        0.15506        0.201511        0.0081766        0.0000317        -0.112136        -0.005482        0.000189        -0.000138        37        O

12/26/2023        60304        0.151962        0.20183        0.0082315        -0.0001214        -0.111834        -0.005682        0.000196        -0.000137        37        O

12/27/2023        60305        0.148892        0.201572        0.0083827        -0.0001818        -0.111595        -0.005936        0.000204        -0.00014        37        O

12/28/2023        60306        0.146072        0.201391        0.0085784        -0.0002035        -0.111475        -0.006102        0.00021        -0.000146        37        O

12/29/2023        60307        0.143398        0.201376        0.0087799        -0.00017        -0.111372        -0.006094        0.000216        -0.000152        37        O

12/30/2023        60308        0.141083        0.201513        0.0088907        -0.0000427        -0.111171        -0.005959        0.000219        -0.000155        37        O

12/31/2023        60309        0.138974        0.201947        0.0088494        0.0001109        -0.110885        -0.005822        0.00022        -0.000156        37        O

1/1/2024        60310        0.136893        0.202227        0.0086824        0.0002271        -0.110618        -0.005744        0.000217        -0.000155        37        O

1/2/2024        60311        0.134898        0.202522        0.0084039        0.0003261        -0.110441        -0.005669        0.000212        -0.000155        37        O

1/3/2024        60312        0.133126        0.203145        0.0080429        0.0003908        -0.110393        -0.005526        0.000205        -0.000159        37        O

1/4/2024        60313        0.131368        0.203986        0.0076366        0.0004143        -0.110547        -0.005361        0.000197        -0.000165        37        O