(221) Eos
ephemeris	date	magn	radius	delta	ra	dec	elong	phase
Today	20 Sep 2026	12.4	2.819 AU	2.060 AU	03h04m	+02°57'	130.7°	15.7°
Opposition	31 Oct 2026	11.8	2.855 AU	1.888 AU	02h43m	-01°07'	163.9°	5.5°

The interactive orbit chart above shows the body's path through the solar system and its position at the given date. Green and blue lines are shown perpendicular to the ecliptic plane: Green if the path is above the ecliptic plane, blue if it is below. (Left-click and drag to rotate the view; Right-click and drag to move the view; Use scroll wheel to zoom in our out.)

The orbital elements of Eos are:

            e (Eccentricity)                : 0.1008881
            a (Semimajor axis)              : 3.0119012
            i (Inclination)                 : 10.89072
            Ω (Longitude of ascending node) : 141.71100
            ω (Argument of perihelion)      : 192.42898
            M (Mean anomaly)                : 26.70211
            Epoch                           : 2026 Jun 09

            L (Longitude of perihelion)     : 153.92290
            B (Latitude of perihelion)      : -2.33056
            P (Orbital period in years)     : 5.23            
        

The light curve chart below shows the estimated development of the minor planet's magnitude.

The all-sky chart below shows the path of the minor planet over the same period as the light curve. The current position is marked yellow.

The following chart shows the path of the minor planet in the next few days. The field of view is optimized for (~10x50) binoculars and finderscopes.

Ephemerides:

Date       Time       RA (2000)    DEC (2000)    delta   radius  elong  phase   PA    magn
2026-09-20 00:00 UT   03 04 32.8   +02 57 10     2.060    2.819  130.7   15.7   266   12.4 
2026-09-20 07:27 UT   03 04 31.0   +02 55 23     2.057    2.819  131.0   15.6   266   12.4 
2026-09-21 00:00 UT   03 04 26.6   +02 51 26     2.051    2.820  131.6   15.4   266   12.4 
2026-09-22 00:00 UT   03 04 18.9   +02 45 38     2.043    2.821  132.6   15.2   267   12.4 
2026-09-23 00:00 UT   03 04 09.8   +02 39 47     2.035    2.821  133.5   14.9   267   12.3 
2026-09-24 00:00 UT   03 03 59.2   +02 33 52     2.027    2.822  134.5   14.7   268   12.3 
2026-09-25 00:00 UT   03 03 47.2   +02 27 53     2.019    2.823  135.5   14.4   268   12.3 
2026-09-26 00:00 UT   03 03 33.8   +02 21 50     2.011    2.824  136.5   14.2   269   12.3 
2026-09-27 00:00 UT   03 03 18.9   +02 15 45     2.004    2.825  137.4   13.9   270   12.3 
2026-09-28 00:00 UT   03 03 02.7   +02 09 37     1.997    2.826  138.4   13.6   270   12.3 
2026-09-29 00:00 UT   03 02 45.0   +02 03 27     1.990    2.827  139.4   13.3   271   12.2 
2026-09-30 00:00 UT   03 02 26.0   +01 57 14     1.983    2.827  140.4   13.1   272   12.2 
2026-10-01 00:00 UT   03 02 05.5   +01 50 58     1.976    2.828  141.4   12.8   272   12.2 
2026-10-02 00:00 UT   03 01 43.7   +01 44 42     1.970    2.829  142.3   12.5   273   12.2 
2026-10-03 00:00 UT   03 01 20.6   +01 38 23     1.963    2.830  143.3   12.2   274   12.2 
2026-10-04 00:00 UT   03 00 56.1   +01 32 04     1.957    2.831  144.3   11.9   275   12.1 
2026-10-05 00:00 UT   03 00 30.3   +01 25 43     1.952    2.832  145.3   11.6   276   12.1 
2026-10-06 00:00 UT   03 00 03.2   +01 19 22     1.946    2.832  146.2   11.3   277   12.1 
2026-10-07 00:00 UT   02 59 34.9   +01 13 01     1.941    2.833  147.2   11.0   278   12.1 
2026-10-08 00:00 UT   02 59 05.3   +01 06 40     1.936    2.834  148.2   10.7   279   12.1 
2026-10-09 00:00 UT   02 58 34.5   +01 00 19     1.931    2.835  149.1   10.4   280   12.1 
2026-10-10 00:00 UT   02 58 02.5   +00 53 59     1.926    2.836  150.1   10.1   281   12.0 
2026-10-11 00:00 UT   02 57 29.3   +00 47 40     1.922    2.837  151.0    9.8   283   12.0 
2026-10-12 00:00 UT   02 56 55.1   +00 41 23     1.917    2.838  152.0    9.5   284   12.0 
2026-10-13 00:00 UT   02 56 19.8   +00 35 08     1.913    2.839  152.9    9.2   286   12.0 
2026-10-14 00:00 UT   02 55 43.4   +00 28 55     1.910    2.839  153.8    8.9   287   12.0 
2026-10-15 00:00 UT   02 55 06.0   +00 22 45     1.906    2.840  154.7    8.6   289   12.0 
2026-10-16 00:00 UT   02 54 27.7   +00 16 38     1.903    2.841  155.6    8.3   291   12.0 
2026-10-17 00:00 UT   02 53 48.5   +00 10 34     1.900    2.842  156.4    8.1   293   11.9 
2026-10-18 00:00 UT   02 53 08.4   +00 04 34     1.898    2.843  157.3    7.8   295   11.9 
2026-10-19 00:00 UT   02 52 27.5   +00 01 22     1.895    2.844  158.1    7.5   297   11.9 
2026-10-20 00:00 UT   02 51 45.8   +00 07 13     1.893    2.845  158.8    7.3   300   11.9 

    Terminology:
            
    delta:  distance between minor planet and earth in AU
    radius: distance between minor planet and sun in AU
    magn:   magnitude (brightness) estimate    
    ra:     right ascension in hours (24h = 360deg)
    dec:    declination in degrees
    elong:  elongation in degrees (angle sun-earth-minor planet)    
    phase:  phase angle in degrees (angle sun-minor planet-earth)        
    AU:     Astronomical Unit (mean distance between earth and sun: 149597870.7 km
    

Orbital elements provided by the MPC (Minor Planet Center).
Calculations by a modified version of AAPlus, a C# implementation of the AA+ project by PJ Naughter from the algorithms presented in the book "Astronomical Algorithms" by Jean Meeus.
NGC2000 dso catalog and star labels from VizieR as provided by the Strasbourg astronomical Data Center.
Tycho2 catalog from the ESO archive.