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

Positions of STEREO A and B for 26-Apr-2025 12:00 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)      1.017902        1.006350        0.955773        0.708078        0.566983        0.429434
Semidiameter (arcsec)            942.750         953.573        1004.033        1355.257        1692.514        2234.631

HCI longitude                    102.253         140.615         174.226         243.938         308.936         216.157
HCI latitude                      -7.132          -4.614          -0.655           3.488          16.786          -1.965

Carrington longitude             316.020         354.381          27.992          97.704         162.703          69.924
Carrington rotation number      2297.122        2297.016        2296.922        2296.729        2296.548        2296.806

Heliographic (HEEQ) longitude    -38.362           0.000          33.611         103.323         168.321          75.542
Heliographic (HEEQ) latitude      -7.132          -4.614          -0.655           3.488          16.786          -1.965

HAE longitude                    177.923         216.155         249.955         319.716          23.583         291.502

Earth Ecliptic (HEE) longitude   -38.232           0.000          33.800         103.561         167.427          75.347
Earth Ecliptic (HEE) latitude     -0.044          -0.000           0.075          -3.030          11.099          -6.229

Roll from ecliptic north          -0.059                          -0.113
Roll from solar north             -1.594                          -7.327

Light travel time to Earth (min)           5.514           4.761                  11.306          12.958           8.233

Separation angle with Earth               38.232          33.800                 103.542         163.289          75.436
Separation angle A with B                         72.032

Carrington rotation 2297 runs from 2025-04-26 01:47 (DOY 116.07) to
2025-05-23 07:15 (DOY 143.30), as seen from Earth.

Last Revised: Saturday, 26-Apr-2025 12:01:05 UTC
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