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

Positions of STEREO A and B for 3-Apr-2025 10:00 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)      1.006674        0.999904        0.957911        0.429394        0.301054        0.446932
Semidiameter (arcsec)            953.266         959.720        1001.792        2234.841        3187.562        2147.145

HCI longitude                     79.410         117.976         150.026         224.221         215.270         147.948
HCI latitude                      -7.098          -6.411          -3.608           2.725          -2.561          -3.274

Carrington longitude             260.600         299.166         331.215          45.410          36.460         329.138
Carrington rotation number      2296.276        2296.169        2296.080        2295.874        2295.899        2296.086

Heliographic (HEEQ) longitude    -38.566          -0.000          32.049         106.245          97.294          29.972
Heliographic (HEEQ) latitude      -7.098          -6.411          -3.608           2.725          -2.561          -3.274

HAE longitude                    155.258         193.552         225.595         300.004         290.553         223.570

Earth Ecliptic (HEE) longitude   -38.294          -0.000          32.043         106.452          97.001          30.018
Earth Ecliptic (HEE) latitude      0.033           0.000           0.027          -2.339          -6.730           0.584

Roll from ecliptic north           0.039                          -0.045
Roll from solar north              1.368                          -6.322

Light travel time to Earth (min)           5.474           4.507                   9.936           8.971           5.427

Separation angle with Earth               38.294          32.043                 106.438          96.953          30.023
Separation angle A with B                         70.337

Carrington rotation 2296 runs from 2025-03-29 19:19 (DOY  88.80) to
2025-04-26 01:47 (DOY 116.07), as seen from Earth.

Last Revised: Thursday, 03-Apr-2025 10:01:07 UTC
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