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

Positions of STEREO A and B for 16-Mar-2025 04:00 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)      1.001392        0.994708        0.959979        0.310187        0.433975        0.367524
Semidiameter (arcsec)            958.294         964.734         999.634        3093.704        2211.253        2611.065

HCI longitude                     61.091          99.778         130.884         284.459         105.135          83.215
HCI latitude                      -6.266          -7.147          -5.508           3.728         -14.880          -0.669

Carrington longitude             141.146         179.833         210.939           4.514         185.190         163.270
Carrington rotation number      2295.608        2295.500        2295.414        2295.987        2295.486        2295.546

Heliographic (HEEQ) longitude    -38.687          -0.000          31.107        -175.319           5.357         -16.563
Heliographic (HEEQ) latitude      -6.266          -7.147          -5.508           3.728         -14.880          -0.669

HAE longitude                    137.045         175.467         206.422           0.218         180.524         158.937

Earth Ecliptic (HEE) longitude   -38.422           0.000          30.955        -175.249           5.056         -16.530
Earth Ecliptic (HEE) latitude      0.092           0.000          -0.015          -3.294          -7.873           6.533

Roll from ecliptic north           0.113                           0.022
Roll from solar north              3.612                          -4.717

Light travel time to Earth (min)           5.463           4.347                  10.843           4.748           5.442

Separation angle with Earth               38.422          30.955                 174.220           9.348          17.740
Separation angle A with B                         69.376

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: Sunday, 16-Mar-2025 04:01:06 UTC
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