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

Positions of STEREO A and B for 26-Apr-2025 09:00 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)      1.017831        1.006317        0.955782        0.707472        0.565503        0.429905
Semidiameter (arcsec)            942.817         953.604        1004.023        1356.418        1696.947        2232.186

HCI longitude                    102.131         140.493         174.095         243.865         308.669         215.753
HCI latitude                      -7.135          -4.626          -0.672           3.486          16.779          -1.984

Carrington longitude             317.671         356.033          29.634          99.405         164.209          71.293
Carrington rotation number      2297.118        2297.011        2296.918        2296.724        2296.544        2296.802

Heliographic (HEEQ) longitude    -38.362          -0.000          33.601         103.372         168.176          75.260
Heliographic (HEEQ) latitude      -7.135          -4.626          -0.672           3.486          16.779          -1.984

HAE longitude                    177.801         216.033         249.823         319.644          23.324         291.096

Earth Ecliptic (HEE) longitude   -38.232           0.000          33.790         103.611         167.290          75.063
Earth Ecliptic (HEE) latitude     -0.044          -0.000           0.075          -3.028          11.072          -6.206

Roll from ecliptic north          -0.059                          -0.112
Roll from solar north             -1.579                          -7.325

Light travel time to Earth (min)           5.514           4.760                  11.306          12.944           8.216

Separation angle with Earth               38.232          33.790                 103.591         163.204          75.152
Separation angle A with B                         72.022

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 09:01:06 UTC
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