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

Positions of STEREO A and B for 10-Mar-2025 21:00 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)      1.000558        0.993288        0.960605        0.442311        0.502735        0.338766
Semidiameter (arcsec)            959.093         966.112         998.983        2169.577        1908.815        2832.712

HCI longitude                     55.763          94.461         125.331         273.487          89.015          57.865
HCI latitude                      -5.900          -7.230          -5.952           3.851         -12.133           0.812

Carrington longitude             210.877         249.575         280.445          68.601         244.129         212.979
Carrington rotation number      2295.414        2295.307        2295.221        2294.809        2295.322        2295.408

Heliographic (HEEQ) longitude    -38.698           0.000          30.870         179.026          -5.446         -36.596
Heliographic (HEEQ) latitude      -5.900          -7.230          -5.952           3.851         -12.133           0.812

HAE longitude                    131.735         170.191         200.878         349.251         164.799         133.367

Earth Ecliptic (HEE) longitude   -38.456          -0.000          30.687         179.060          -5.392         -36.823
Earth Ecliptic (HEE) latitude      0.108           0.000          -0.027          -3.388          -4.881           6.948

Roll from ecliptic north           0.133                           0.042
Roll from solar north              4.206                          -4.144

Light travel time to Earth (min)           5.462           4.308                  11.936           4.148           6.261

Separation angle with Earth               38.456          30.687                 176.484           7.269          37.382
Separation angle A with B                         69.143

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: Monday, 10-Mar-2025 21:01:07 UTC
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