Information about STEREO-A close approach to Earth, August 2023

Positions of STEREO A and B for 27-Mar-2025 15:00 UT

This figure plots the current positions of the STEREO Ahead (red) and Behind (blue) spacecraft relative to the Sun (yellow) and Earth (green). The dotted lines show the angular displacement from the Sun. Units are in A.U.

When the two spacecraft are close to Earth, an expanded view of the region around Earth will appear on the right, in the same orientation as the Sun-centered view.

Other resources:

• STEREO Orbit Tool
• STEREO-A Fly-by Orbit Tool for Summer 2023
• STEREO-A roll angle during Fly-By
• STEREO orbit simulations
• Satellite Situation Center (SSCWeb)
• HelioWeb
• Attitude and orbit text files (CalTech)
• Early orbit summary
• Connections with Parker Solar Probe
• Explanation of coordinate systems

                                STEREO-B           Earth        STEREO-A       Parker SP   Solar Orbiter     BepiColombo

Heliocentric distance (AU)      1.004291        0.997976        0.958656        0.242301        0.307276        0.425035
Semidiameter (arcsec)            955.528         961.573        1001.014        3960.471        3123.012        2257.764

HCI longitude                     72.609         111.231         142.905         206.163         165.708         126.657
HCI latitude                      -6.869          -6.763          -4.375           1.743         -14.407          -2.759

Carrington longitude             350.134          28.756          60.430         123.688          83.233          44.182
Carrington rotation number      2296.027        2295.920        2295.832        2295.656        2295.769        2295.877

Heliographic (HEEQ) longitude    -38.622           0.000          31.673          94.932          54.477          15.425
Heliographic (HEEQ) latitude      -6.869          -6.763          -4.375           1.743         -14.407          -2.759

HAE longitude                    148.503         186.842         218.450         281.945         239.796         202.434

Earth Ecliptic (HEE) longitude   -38.339          -0.000          31.608          95.103          52.954          15.592
Earth Ecliptic (HEE) latitude      0.056           0.000           0.011          -1.462         -12.515           3.060

Roll from ecliptic north           0.067                          -0.020
Roll from solar north              2.229                          -5.799

Light travel time to Earth (min)           5.469           4.443                   8.714           7.105           4.995

Separation angle with Earth               38.339          31.608                  95.101          53.975          15.882
Separation angle A with B                         69.947

Carrington rotation 2295 runs from 2025-03-02 11:51 (DOY  61.49) to
2025-03-29 19:19 (DOY  88.80), as seen from Earth.

Last Revised: Thursday, 27-Mar-2025 15:01:06 UTC
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