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

Positions of STEREO A and B for 20-Apr-2025 01:00 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)      1.014334        1.004579        0.956296        0.665807        0.486804        0.448730
Semidiameter (arcsec)            946.067         955.254        1003.484        1441.299        1971.280        2138.541

HCI longitude                     95.915         134.322         167.453         239.987         293.000         196.206
HCI latitude                      -7.237          -5.199          -1.518           3.366          15.804          -2.782

Carrington longitude              41.289          79.696         112.827         185.361         238.374         141.580
Carrington rotation number      2296.885        2296.779        2296.687        2296.485        2296.338        2296.607

Heliographic (HEEQ) longitude    -38.407           0.000          33.131         105.665         158.677          61.884
Heliographic (HEEQ) latitude      -7.237          -5.199          -1.518           3.366          15.804          -2.782

HAE longitude                    171.634         209.858         243.129         315.767           8.147         271.511

Earth Ecliptic (HEE) longitude   -38.225          -0.000          33.271         105.909         158.288          61.652
Earth Ecliptic (HEE) latitude     -0.023           0.000           0.062          -2.918           9.113          -4.784

Roll from ecliptic north          -0.033                          -0.096
Roll from solar north             -0.778                          -7.173

Light travel time to Earth (min)           5.499           4.685                  11.217          12.177           7.364

Separation angle with Earth               38.225          33.271                 105.888         156.538          61.760
Separation angle A with B                         71.495

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: Sunday, 20-Apr-2025 01:01:05 UTC
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