(106) Dione
ephemeris	date	magn	radius	delta	ra	dec	elong	phase
Today	18 Sep 2025	13.7	3.272 AU	3.083 AU	17h45m	-26°41'	91.7°	17.9°
Opposition	18 Sep 2026	11.5	2.757 AU	1.756 AU	23h56m	-07°32'	173.3°	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 Dione are:

            e (Eccentricity)                : 0.1588532
            a (Semimajor axis)              : 3.1824910
            i (Inclination)                 : 4.57500
            Ω (Longitude of ascending node) : 61.98311
            ω (Argument of perihelion)      : 331.74654
            M (Mean anomaly)                : 279.92762
            Epoch                           : 2025 Nov 21

            L (Longitude of perihelion)     : 33.80583
            B (Latitude of perihelion)      : -2.16389
            P (Orbital period in years)     : 5.68            
        

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
2025-09-18 00:00 UT   17 45 18.1   -26 41 22     3.083    3.272   91.7   17.9    91   13.7 
2025-09-18 01:44 UT   17 45 21.0   -26 41 21     3.084    3.271   91.7   17.9    91   13.7 
2025-09-19 00:00 UT   17 45 59.0   -26 41 17     3.096    3.270   90.9   17.9    91   13.7 
2025-09-20 00:00 UT   17 46 41.1   -26 41 12     3.109    3.269   90.1   17.9    91   13.7 
2025-09-21 00:00 UT   17 47 24.1   -26 41 06     3.122    3.267   89.3   17.9    91   13.7 
2025-09-22 00:00 UT   17 48 08.3   -26 41 01     3.135    3.266   88.5   17.9    91   13.8 
2025-09-23 00:00 UT   17 48 53.5   -26 40 55     3.148    3.264   87.6   17.9    91   13.8 
2025-09-24 00:00 UT   17 49 39.7   -26 40 48     3.160    3.263   86.8   17.9    91   13.8 
2025-09-25 00:00 UT   17 50 26.9   -26 40 41     3.173    3.261   86.0   17.9    91   13.8 
2025-09-26 00:00 UT   17 51 15.1   -26 40 33     3.186    3.260   85.2   17.9    91   13.8 
2025-09-27 00:00 UT   17 52 04.3   -26 40 25     3.199    3.258   84.4   17.8    91   13.8 
2025-09-28 00:00 UT   17 52 54.5   -26 40 16     3.212    3.257   83.6   17.8    91   13.8 
2025-09-29 00:00 UT   17 53 45.6   -26 40 06     3.224    3.255   82.9   17.8    91   13.8 
2025-09-30 00:00 UT   17 54 37.7   -26 39 56     3.237    3.254   82.1   17.7    91   13.8 
2025-10-01 00:00 UT   17 55 30.7   -26 39 45     3.250    3.252   81.3   17.7    91   13.8 
2025-10-02 00:00 UT   17 56 24.6   -26 39 33     3.262    3.251   80.5   17.7    91   13.8 
2025-10-03 00:00 UT   17 57 19.4   -26 39 20     3.275    3.249   79.7   17.6    91   13.8 
2025-10-04 00:00 UT   17 58 15.2   -26 39 06     3.288    3.248   79.0   17.6    91   13.8 
2025-10-05 00:00 UT   17 59 11.8   -26 38 51     3.300    3.246   78.2   17.5    91   13.8 
2025-10-06 00:00 UT   18 00 09.2   -26 38 35     3.313    3.245   77.4   17.5    91   13.8 
2025-10-07 00:00 UT   18 01 07.5   -26 38 18     3.325    3.243   76.6   17.4    91   13.9 
2025-10-08 00:00 UT   18 02 06.7   -26 37 59     3.337    3.242   75.9   17.4    91   13.9 
2025-10-09 00:00 UT   18 03 06.7   -26 37 40     3.350    3.240   75.1   17.3    91   13.9 
2025-10-10 00:00 UT   18 04 07.5   -26 37 19     3.362    3.239   74.4   17.3    90   13.9 
2025-10-11 00:00 UT   18 05 09.2   -26 36 57     3.374    3.237   73.6   17.2    90   13.9 
2025-10-12 00:00 UT   18 06 11.6   -26 36 33     3.387    3.236   72.8   17.1    90   13.9 
2025-10-13 00:00 UT   18 07 14.8   -26 36 08     3.399    3.234   72.1   17.1    90   13.9 
2025-10-14 00:00 UT   18 08 18.8   -26 35 41     3.411    3.233   71.3   17.0    90   13.9 
2025-10-15 00:00 UT   18 09 23.6   -26 35 13     3.423    3.231   70.6   16.9    90   13.9 
2025-10-16 00:00 UT   18 10 29.1   -26 34 44     3.435    3.230   69.9   16.8    90   13.9 
2025-10-17 00:00 UT   18 11 35.4   -26 34 12     3.447    3.228   69.1   16.8    90   13.9 
2025-10-18 00:00 UT   18 12 42.4   -26 33 39     3.458    3.227   68.4   16.7    90   13.9 

    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.