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

Positions of STEREO A and B for 10-Jun-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)      1.047221        1.015161        0.954338        0.376919        0.882667        0.364095
Semidiameter (arcsec)            916.356         945.296        1005.543        2545.977        1087.192        2635.654

HCI longitude                    144.552         183.402         221.291         278.414           3.719          82.458
HCI latitude                      -4.380           0.436           4.928           3.813          11.022          -0.625

Carrington longitude              84.748         123.599         161.487         218.610         303.916          22.654
Carrington rotation number      2298.765        2298.657        2298.551        2298.393        2299.156        2298.937

Heliographic (HEEQ) longitude    -38.850          -0.000          37.889          95.012        -179.683        -100.944
Heliographic (HEEQ) latitude      -4.380           0.436           4.928           3.813          11.022          -0.625

HAE longitude                    220.083         259.196         297.297         354.175          78.048         158.174

Earth Ecliptic (HEE) longitude   -39.112           0.000          38.101          94.980         178.852        -101.021
Earth Ecliptic (HEE) latitude     -0.161          -0.000           0.124          -3.361          11.406           6.565

Roll from ecliptic north          -0.201                          -0.157
Roll from solar north             -6.103                          -5.599

Light travel time to Earth (min)           5.747           5.368                   9.258          15.706           9.496

Separation angle with Earth               39.113          38.101                  94.971         168.538         100.948
Separation angle A with B                         77.214

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: Tuesday, 10-Jun-2025 04:01:08 UTC
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