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

Positions of STEREO A and B for 26-Apr-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)      1.017688        1.006250        0.955801        0.706236        0.562531        0.430835
Semidiameter (arcsec)            942.949         953.667        1004.003        1358.792        1705.909        2227.367

HCI longitude                    101.887         140.250         173.832         243.720         308.131         214.947
HCI latitude                      -7.141          -4.649          -0.705           3.482          16.765          -2.023

Carrington longitude             320.972         359.336          32.918         102.806         167.216          74.033
Carrington rotation number      2297.108        2297.002        2296.909        2296.714        2296.536        2296.794

Heliographic (HEEQ) longitude    -38.364          -0.000          33.582         103.470         167.880          74.697
Heliographic (HEEQ) latitude      -7.141          -4.649          -0.705           3.482          16.765          -2.023

HAE longitude                    177.559         215.790         249.559         319.499          22.801         290.286

Earth Ecliptic (HEE) longitude   -38.231          -0.000          33.769         103.709         167.011          74.496
Earth Ecliptic (HEE) latitude     -0.043          -0.000           0.074          -3.025          11.017          -6.161

Roll from ecliptic north          -0.058                          -0.112
Roll from solar north             -1.548                          -7.321

Light travel time to Earth (min)           5.513           4.757                  11.306          12.917           8.182

Separation angle with Earth               38.231          33.769                 103.690         163.029          74.588
Separation angle A with B                         72.000

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 03:01:05 UTC
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