(113) Amalthea
ephemeris	date	magn	radius	delta	ra	dec	elong	phase
Today	17 Sep 2025	13.4	2.235 AU	2.610 AU	15h19m	-14°55'	57.4°	22.3°
Opposition	11 Sep 2026	11.8	2.539 AU	1.535 AU	23h29m	-09°47'	174.0°	2.4°

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 Amalthea are:

            e (Eccentricity)                : 0.0861659
            a (Semimajor axis)              : 2.3764794
            i (Inclination)                 : 5.04245
            Ω (Longitude of ascending node) : 123.32185
            ω (Argument of perihelion)      : 80.25048
            M (Mean anomaly)                : 60.21116
            Epoch                           : 2025 Nov 21

            L (Longitude of perihelion)     : 203.53518
            B (Latitude of perihelion)      : 4.96944
            P (Orbital period in years)     : 3.66            
        

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
2025-09-17 00:00 UT   15 19 15.8   -14 55 02     2.610    2.235   57.4   22.3   103   13.4 
2025-09-17 22:22 UT   15 20 55.9   -15 02 59     2.620    2.236   56.9   22.1   103   13.4 
2025-09-18 00:00 UT   15 21 03.2   -15 03 33     2.620    2.236   56.9   22.1   103   13.4 
2025-09-19 00:00 UT   15 22 51.2   -15 12 02     2.631    2.236   56.4   22.0   102   13.4 
2025-09-20 00:00 UT   15 24 39.6   -15 20 27     2.641    2.237   55.8   21.8   102   13.5 
2025-09-21 00:00 UT   15 26 28.5   -15 28 49     2.651    2.238   55.3   21.7   102   13.5 
2025-09-22 00:00 UT   15 28 17.8   -15 37 07     2.662    2.239   54.8   21.5   102   13.5 
2025-09-23 00:00 UT   15 30 07.6   -15 45 21     2.672    2.239   54.3   21.3   102   13.5 
2025-09-24 00:00 UT   15 31 57.9   -15 53 32     2.682    2.240   53.8   21.2   102   13.5 
2025-09-25 00:00 UT   15 33 48.6   -16 01 38     2.692    2.241   53.3   21.0   101   13.5 
2025-09-26 00:00 UT   15 35 39.8   -16 09 41     2.702    2.242   52.7   20.9   101   13.5 
2025-09-27 00:00 UT   15 37 31.4   -16 17 40     2.712    2.243   52.2   20.7   101   13.5 
2025-09-28 00:00 UT   15 39 23.4   -16 25 34     2.722    2.243   51.7   20.5   101   13.5 
2025-09-29 00:00 UT   15 41 15.9   -16 33 25     2.732    2.244   51.2   20.4   101   13.5 
2025-09-30 00:00 UT   15 43 08.7   -16 41 11     2.741    2.245   50.7   20.2   101   13.5 
2025-10-01 00:00 UT   15 45 02.0   -16 48 53     2.751    2.246   50.2   20.0   100   13.5 
2025-10-02 00:00 UT   15 46 55.7   -16 56 31     2.761    2.246   49.7   19.9   100   13.5 
2025-10-03 00:00 UT   15 48 49.8   -17 04 04     2.770    2.247   49.1   19.7   100   13.5 
2025-10-04 00:00 UT   15 50 44.3   -17 11 32     2.780    2.248   48.6   19.5   100   13.5 
2025-10-05 00:00 UT   15 52 39.2   -17 18 56     2.789    2.249   48.1   19.3   100   13.5 

    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.