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

Positions of STEREO A and B for 1-Jun-2025 03:00 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)      1.041044        1.013986        0.954289        0.552987        0.851782        0.319130
Semidiameter (arcsec)            921.794         946.392        1005.595        1735.354        1126.612        3007.012

HCI longitude                    136.222         174.817         211.720         266.223         355.855          35.690
HCI latitude                      -5.173          -0.655           3.952           3.855          12.662           1.986

Carrington longitude             204.669         243.264         280.167         334.670          64.302         104.137
Carrington rotation number      2298.431        2298.324        2298.222        2298.070        2298.821        2298.711

Heliographic (HEEQ) longitude    -38.595          -0.000          36.903          91.407        -178.962        -139.126
Heliographic (HEEQ) latitude      -5.173          -0.655           3.952           3.855          12.662           1.986

HAE longitude                    211.745         250.541         287.705         341.991          70.037         111.033

Earth Ecliptic (HEE) longitude   -38.796           0.000          37.164          91.450         179.495        -139.508
Earth Ecliptic (HEE) latitude     -0.143           0.000           0.121          -3.382          12.040           6.202

Roll from ecliptic north          -0.181                          -0.158
Roll from solar north             -5.410                          -6.322

Light travel time to Earth (min)           5.681           5.238                   9.708          15.433          10.584

Separation angle with Earth               38.797          37.164                  91.447         167.950         139.117
Separation angle A with B                         75.961

Carrington rotation 2298 runs from 2025-05-23 07:15 (DOY 143.30) to
2025-06-19 12:06 (DOY 170.50), as seen from Earth.

Last Revised: Sunday, 01-Jun-2025 03:01:06 UTC
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