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

Positions of STEREO A and B for 21-Mar-2025 05:00 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)      1.002487        0.996127        0.959389        0.120720        0.369758        0.395045
Semidiameter (arcsec)            957.247         963.359        1000.249        7949.173        2595.286        2429.160

HCI longitude                     66.163         104.828         136.174         320.563         126.538         103.903
HCI latitude                      -6.564          -7.012          -5.037           2.421         -16.716          -1.794

Carrington longitude              74.705         113.370         144.716         329.105         135.080         112.445
Carrington rotation number      2295.792        2295.685        2295.598        2296.086        2295.625        2295.688

Heliographic (HEEQ) longitude    -38.664           0.000          31.347        -144.265          21.710          -0.925
Heliographic (HEEQ) latitude      -6.564          -7.012          -5.037           2.421         -16.716          -1.794

HAE longitude                    142.095         180.480         211.710          36.317         201.256         179.721

Earth Ecliptic (HEE) longitude   -38.385           0.000          31.230        -144.163          20.776          -0.759
Earth Ecliptic (HEE) latitude      0.076           0.000          -0.004          -2.187         -10.849           5.245

Roll from ecliptic north           0.093                           0.004
Roll from solar north              3.017                          -5.222

Light travel time to Earth (min)           5.465           4.388                   9.117           5.595           5.023

Separation angle with Earth               38.385          31.230                 144.105          23.326           5.299
Separation angle A with B                         69.615

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: Friday, 21-Mar-2025 05:01:07 UTC
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