Positions of STEREO A and B for 8-Dec-2025 17:00 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)      1.049595        0.985015        0.966959        0.238980        0.899956        0.406459
Semidiameter (arcsec)            914.284         974.227         992.418        4015.522        1066.305        2360.946

HCI longitude                    303.470           0.728          50.970         292.980          14.242         110.740
HCI latitude                       6.168          -0.096          -5.773           3.539           8.485          -2.121

Carrington longitude             188.607         245.865         296.107         178.117         259.379         355.877
Carrington rotation number      2305.476        2305.317        2305.177        2305.505        2305.280        2305.011

Heliographic (HEEQ) longitude    -57.258           0.000          50.242         -67.748          13.514         110.012
Heliographic (HEEQ) latitude       6.168          -0.096          -5.773           3.539           8.485          -2.121

HAE longitude                     19.017          76.500         126.971           8.736          88.847         186.563

Earth Ecliptic (HEE) longitude   -57.483           0.000          50.471         -67.764          12.347         110.063
Earth Ecliptic (HEE) latitude      0.110          -0.000          -0.125          -3.138          10.204           4.660

Roll from ecliptic north           0.073                           0.101
Roll from solar north              4.065                           4.660

Light travel time to Earth (min)           8.151           6.923                   7.666           2.287           9.874

Separation angle with Earth               57.483          50.471                  67.799          15.967         109.994
Separation angle A with B                        107.954

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: Monday, 08-Dec-2025 17:01:09 UTC
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