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

Positions of STEREO A and B for 9-Jan-2025 11:00 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)      1.013862        0.983385        0.966496        0.516105        0.944192        0.451098
Semidiameter (arcsec)            946.507         975.841         992.894        1859.366        1016.348        2127.316

HCI longitude                    355.750          33.115          62.089         230.047          17.661         153.434
HCI latitude                       0.735          -3.980          -6.539           2.989           1.880          -3.337

Carrington longitude             287.838         325.203         354.178         162.135         309.749          85.522
Carrington rotation number      2293.200        2293.097        2293.016        2293.550        2293.140        2292.762

Heliographic (HEEQ) longitude    -37.365           0.000          28.975        -163.067         -15.454         120.319
Heliographic (HEEQ) latitude       0.735          -3.980          -6.539           2.989           1.880          -3.337

HAE longitude                     71.457         109.092         138.052         305.830          93.067         229.006

Earth Ecliptic (HEE) longitude   -37.635          -0.000          28.961        -163.262         -16.025         119.915
Earth Ecliptic (HEE) latitude      0.196           0.000          -0.121          -2.576           4.064          -0.082

Roll from ecliptic north           0.255                           0.216
Roll from solar north              7.487                           3.604

Light travel time to Earth (min)           5.364           4.058                  12.349           2.326          10.563

Separation angle with Earth               37.635          28.961                 163.070          16.519         119.915
Separation angle A with B                         66.596

Carrington rotation 2293 runs from 2025-01-06 19:35 (DOY   6.82) to
2025-02-03 03:45 (DOY  34.16), as seen from Earth.

Last Revised: Thursday, 09-Jan-2025 11:01:05 UTC
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