(221) Eos
ephemeris	date	magn	radius	delta	ra	dec	elong	phase
Opposition	13 Jul 2025	11.5	2.777 AU	1.768 AU	19h28m	-13°04'	171.3°	3.2°
Today	20 Jul 2025	11.5	2.773 AU	1.768 AU	19h23m	-13°39'	169.3°	3.9°

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)                : 0.1012016
            a (Semimajor axis)              : 3.0129160
            i (Inclination)                 : 10.88932
            Ω (Longitude of ascending node) : 141.71231
            ω (Argument of perihelion)      : 192.48734
            M (Mean anomaly)                : 311.25730
            Epoch                           : 2025 May 05

            L (Longitude of perihelion)     : 153.98167
            B (Latitude of perihelion)      : -2.34103
            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. A more printer-friendly version of the same chart can be found below.

Ephemerides:

Date       Time       RA (2000)    DEC (2000)    delta   radius  elong  phase   PA    magn
2025-07-20 00:00 UT   19 23 19.8   -13 39 20     1.768    2.773  169.3    3.9   132   11.5 
2025-07-20 07:34 UT   19 23 04.9   -13 41 05     1.768    2.772  169.1    4.0   131   11.5 
2025-07-21 00:00 UT   19 22 32.6   -13 44 53     1.769    2.772  168.6    4.2   128   11.6 
2025-07-22 00:00 UT   19 21 45.6   -13 50 29     1.770    2.771  167.8    4.4   124   11.6 
2025-07-23 00:00 UT   19 20 59.1   -13 56 08     1.771    2.771  167.0    4.7   120   11.6 
2025-07-24 00:00 UT   19 20 13.1   -14 01 50     1.773    2.770  166.1    5.1   117   11.6 
2025-07-25 00:00 UT   19 19 27.6   -14 07 33     1.775    2.769  165.2    5.4   114   11.6 
2025-07-26 00:00 UT   19 18 42.6   -14 13 19     1.777    2.769  164.2    5.7   112   11.6 
2025-07-27 00:00 UT   19 17 58.3   -14 19 06     1.780    2.768  163.3    6.1   110   11.7 
2025-07-28 00:00 UT   19 17 14.8   -14 24 55     1.783    2.767  162.3    6.4   108   11.7 
2025-07-29 00:00 UT   19 16 31.9   -14 30 45     1.786    2.767  161.3    6.8   106   11.7 
2025-07-30 00:00 UT   19 15 49.8   -14 36 36     1.789    2.766  160.3    7.1   104   11.7 
2025-07-31 00:00 UT   19 15 08.6   -14 42 28     1.793    2.765  159.2    7.5   103   11.7 
2025-08-01 00:00 UT   19 14 28.3   -14 48 20     1.797    2.765  158.2    7.8   102   11.8 
2025-08-02 00:00 UT   19 13 48.9   -14 54 13     1.801    2.764  157.2    8.2   101   11.8 
2025-08-03 00:00 UT   19 13 10.5   -15 00 06     1.805    2.764  156.1    8.5   100   11.8 
2025-08-04 00:00 UT   19 12 33.1   -15 05 59     1.809    2.763  155.1    8.9    99   11.8 
2025-08-05 00:00 UT   19 11 56.8   -15 11 52     1.814    2.762  154.0    9.3    98   11.8 
2025-08-06 00:00 UT   19 11 21.5   -15 17 44     1.819    2.762  153.0    9.6    97   11.9 
2025-08-07 00:00 UT   19 10 47.4   -15 23 36     1.825    2.761  151.9    9.9    96   11.9 
2025-08-08 00:00 UT   19 10 14.5   -15 29 27     1.830    2.760  150.9   10.3    96   11.9 
2025-08-09 00:00 UT   19 09 42.8   -15 35 16     1.836    2.760  149.8   10.6    95   11.9 
2025-08-10 00:00 UT   19 09 12.3   -15 41 05     1.842    2.759  148.8   11.0    94   11.9 
2025-08-11 00:00 UT   19 08 43.0   -15 46 52     1.848    2.759  147.8   11.3    94   12.0 
2025-08-12 00:00 UT   19 08 15.0   -15 52 38     1.854    2.758  146.7   11.6    93   12.0 
2025-08-13 00:00 UT   19 07 48.4   -15 58 22     1.861    2.757  145.7   12.0    93   12.0 
2025-08-14 00:00 UT   19 07 23.0   -16 04 05     1.868    2.757  144.6   12.3    92   12.0 
2025-08-15 00:00 UT   19 06 59.1   -16 09 45     1.875    2.756  143.6   12.6    92   12.0 
2025-08-16 00:00 UT   19 06 36.5   -16 15 24     1.882    2.756  142.6   12.9    92   12.1 
2025-08-17 00:00 UT   19 06 15.3   -16 20 60     1.889    2.755  141.5   13.2    91   12.1 
2025-08-18 00:00 UT   19 05 55.5   -16 26 34     1.897    2.754  140.5   13.5    91   12.1 
2025-08-19 00:00 UT   19 05 37.2   -16 32 05     1.905    2.754  139.5   13.8    91   12.1 

    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.