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

Positions of STEREO A and B for 4-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)      1.006917        1.000079        0.957845        0.442813        0.304310        0.448362
Semidiameter (arcsec)            953.036         959.552        1001.861        2167.115        3153.454        2140.296

HCI longitude                     80.034         118.595         150.681         225.173         219.562         149.815
HCI latitude                      -7.114          -6.374          -3.535           2.770          -1.272          -3.298

Carrington longitude             252.359         290.919         323.005          37.497          31.886         322.140
Carrington rotation number      2296.299        2296.192        2296.103        2295.896        2295.911        2296.105

Heliographic (HEEQ) longitude    -38.560          -0.000          32.086         106.578         100.967          31.220
Heliographic (HEEQ) latitude      -7.114          -6.374          -3.535           2.770          -1.272          -3.298

HAE longitude                    155.878         194.168         226.253         300.956         294.977         225.420

Earth Ecliptic (HEE) longitude   -38.290           0.000          32.085         106.788         100.809          31.253
Earth Ecliptic (HEE) latitude      0.031           0.000           0.028          -2.380          -5.880           0.358

Roll from ecliptic north           0.036                          -0.047
Roll from solar north              1.288                          -6.366

Light travel time to Earth (min)           5.475           4.513                  10.022           9.135           5.483

Separation angle with Earth               38.290          32.085                 106.773         100.752          31.254
Separation angle A with B                         70.375

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: Friday, 04-Apr-2025 01:01:05 UTC
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