Positions of STEREO A and B for 24-Dec-2025 14:00 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)      1.038765        0.983615        0.966166        0.425442        0.878526        0.460713
Semidiameter (arcsec)            923.816         975.613         993.233        2255.603        1092.316        2082.919

HCI longitude                    318.132          16.759          67.451         223.939          26.925         160.835
HCI latitude                       5.000          -2.105          -6.822           2.712           5.012          -3.371

Carrington longitude             338.092          36.719          87.411         243.898          46.885         180.795
Carrington rotation number      2306.061        2305.898        2305.757        2306.323        2305.870        2305.498

Heliographic (HEEQ) longitude    -58.627           0.000          50.692        -152.821          10.166         144.076
Heliographic (HEEQ) latitude       5.000          -2.105          -6.822           2.712           5.012          -3.371

HAE longitude                     33.656          92.653         143.385         299.722         101.935         236.341

Earth Ecliptic (HEE) longitude   -58.997           0.000          50.732        -152.931           9.282         143.688
Earth Ecliptic (HEE) latitude      0.148           0.000          -0.118          -2.327           8.260          -0.975

Roll from ecliptic north           0.091                           0.093
Roll from solar north              5.485                           2.868

Light travel time to Earth (min)           8.292           6.949                  11.444           1.885          11.495

Separation angle with Earth               58.998          50.732                 152.839          12.401         143.677
Separation angle A with B                        109.730

Carrington rotation 2305 runs from 2025-11-30 01:08 (DOY 334.05) to
2025-12-27 08:54 (DOY 361.37), as seen from Earth.

Last Revised: Wednesday, 24-Dec-2025 14:01:11 UTC
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