(221) Eos
ephemeris	date	magn	radius	delta	ra	dec	elong	phase
Today	18 Nov 2025	13.2	2.716 AU	2.979 AU	20h11m	-19°42'	65.1°	19.3°
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)                : 0.1010595
            a (Semimajor axis)              : 3.0125182
            i (Inclination)                 : 10.89026
            Ω (Longitude of ascending node) : 141.71015
            ω (Argument of perihelion)      : 192.48158
            M (Mean anomaly)                : 348.95146
            Epoch                           : 2025 Nov 21

            L (Longitude of perihelion)     : 153.97381
            B (Latitude of perihelion)      : -2.34017
            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
2025-11-18 00:00 UT   20 11 12.1   -19 42 21     2.979    2.716   65.1   19.3    77   13.2 
2025-11-18 02:37 UT   20 11 21.5   -19 42 08     2.981    2.716   65.1   19.3    77   13.2 
2025-11-19 00:00 UT   20 12 38.7   -19 40 20     2.991    2.716   64.5   19.2    77   13.2 
2025-11-20 00:00 UT   20 14 05.9   -19 38 14     3.003    2.715   63.8   19.1    77   13.2 
2025-11-21 00:00 UT   20 15 33.5   -19 36 02     3.015    2.715   63.1   18.9    77   13.3 
2025-11-22 00:00 UT   20 17 01.7   -19 33 44     3.026    2.715   62.5   18.8    77   13.3 
2025-11-23 00:00 UT   20 18 30.3   -19 31 21     3.038    2.715   61.8   18.7    77   13.3 
2025-11-24 00:00 UT   20 19 59.4   -19 28 52     3.050    2.714   61.1   18.6    77   13.3 
2025-11-25 00:00 UT   20 21 29.0   -19 26 18     3.061    2.714   60.5   18.5    77   13.3 
2025-11-26 00:00 UT   20 22 59.0   -19 23 38     3.073    2.714   59.8   18.3    77   13.3 
2025-11-27 00:00 UT   20 24 29.4   -19 20 53     3.084    2.714   59.2   18.2    76   13.3 
2025-11-28 00:00 UT   20 26 00.3   -19 18 03     3.095    2.713   58.5   18.1    76   13.3 
2025-11-29 00:00 UT   20 27 31.6   -19 15 07     3.106    2.713   57.9   17.9    76   13.3 
2025-11-30 00:00 UT   20 29 03.3   -19 12 05     3.117    2.713   57.2   17.8    76   13.3 
2025-12-01 00:00 UT   20 30 35.3   -19 08 58     3.129    2.713   56.6   17.7    76   13.3 
2025-12-02 00:00 UT   20 32 07.8   -19 05 46     3.139    2.713   55.9   17.5    76   13.3 
2025-12-03 00:00 UT   20 33 40.6   -19 02 28     3.150    2.712   55.3   17.4    76   13.3 
2025-12-04 00:00 UT   20 35 13.7   -18 59 06     3.161    2.712   54.6   17.2    76   13.3 
2025-12-05 00:00 UT   20 36 47.2   -18 55 38     3.172    2.712   54.0   17.1    76   13.3 
2025-12-06 00:00 UT   20 38 21.1   -18 52 04     3.183    2.712   53.3   16.9    76   13.3 
2025-12-07 00:00 UT   20 39 55.3   -18 48 26     3.193    2.712   52.7   16.8    76   13.3 
2025-12-08 00:00 UT   20 41 29.8   -18 44 42     3.204    2.712   52.1   16.6    75   13.3 
2025-12-09 00:00 UT   20 43 04.6   -18 40 53     3.214    2.711   51.4   16.5    75   13.3 
2025-12-10 00:00 UT   20 44 39.7   -18 36 59     3.224    2.711   50.8   16.3    75   13.3 
2025-12-11 00:00 UT   20 46 15.1   -18 32 59     3.235    2.711   50.2   16.2    75   13.3 

    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.