(85) Io
ephemeris	date	magn	radius	delta	ra	dec	elong	phase
Opposition	16 Oct 2025	10.4	2.313 AU	1.316 AU	01h27m	+09°02'	179.5°	0.2°
Today	17 Nov 2025	11.5	2.371 AU	1.505 AU	01h09m	+04°07'	143.0°	14.5°

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 Io are:

            e (Eccentricity)                : 0.1930854
            a (Semimajor axis)              : 2.6530325
            i (Inclination)                 : 11.96082
            Ω (Longitude of ascending node) : 203.04207
            ω (Argument of perihelion)      : 122.89557
            M (Mean anomaly)                : 48.27419
            Epoch                           : 2025 Nov 21

            L (Longitude of perihelion)     : 146.51370
            B (Latitude of perihelion)      : 10.02128
            P (Orbital period in years)     : 4.32            
        

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
2025-11-17 00:00 UT   01 09 46.9   +04 07 57     1.505    2.371  143.0   14.5    64   11.5 
2025-11-17 17:32 UT   01 09 37.7   +04 03 33     1.512    2.372  142.2   14.8    64   11.5 
2025-11-18 00:00 UT   01 09 34.5   +04 01 58     1.515    2.373  141.9   14.9    64   11.5 
2025-11-19 00:00 UT   01 09 23.6   +03 56 13     1.525    2.375  140.8   15.2    64   11.6 
2025-11-20 00:00 UT   01 09 14.4   +03 50 44     1.535    2.377  139.8   15.6    64   11.6 
2025-11-21 00:00 UT   01 09 06.7   +03 45 30     1.545    2.379  138.7   15.9    64   11.6 
2025-11-22 00:00 UT   01 09 00.6   +03 40 31     1.556    2.381  137.6   16.2    64   11.7 
2025-11-23 00:00 UT   01 08 56.1   +03 35 48     1.567    2.383  136.6   16.6    64   11.7 
2025-11-24 00:00 UT   01 08 53.2   +03 31 19     1.577    2.384  135.5   16.9    64   11.7 
2025-11-25 00:00 UT   01 08 51.9   +03 27 05     1.588    2.386  134.5   17.2    64   11.7 
2025-11-26 00:00 UT   01 08 52.1   +03 23 06     1.600    2.388  133.4   17.5    64   11.8 
2025-11-27 00:00 UT   01 08 54.0   +03 19 23     1.611    2.390  132.4   17.7    64   11.8 
2025-11-28 00:00 UT   01 08 57.4   +03 15 53     1.622    2.392  131.4   18.0    64   11.8 
2025-11-29 00:00 UT   01 09 02.4   +03 12 39     1.634    2.394  130.4   18.3    64   11.8 
2025-11-30 00:00 UT   01 09 09.0   +03 09 39     1.646    2.396  129.4   18.6    64   11.9 
2025-12-01 00:00 UT   01 09 17.1   +03 06 53     1.658    2.398  128.4   18.8    65   11.9 
2025-12-02 00:00 UT   01 09 26.8   +03 04 21     1.670    2.400  127.4   19.1    65   11.9 
2025-12-03 00:00 UT   01 09 37.9   +03 02 04     1.682    2.402  126.4   19.3    65   11.9 
2025-12-04 00:00 UT   01 09 50.6   +03 00 00     1.694    2.404  125.4   19.5    65   12.0 
2025-12-05 00:00 UT   01 10 04.8   +02 58 10     1.707    2.406  124.5   19.7    65   12.0 
2025-12-06 00:00 UT   01 10 20.4   +02 56 33     1.720    2.408  123.5   20.0    65   12.0 
2025-12-07 00:00 UT   01 10 37.6   +02 55 10     1.732    2.410  122.5   20.2    65   12.0 
2025-12-08 00:00 UT   01 10 56.1   +02 53 59     1.745    2.412  121.6   20.4    65   12.1 
2025-12-09 00:00 UT   01 11 16.1   +02 53 02     1.758    2.414  120.6   20.6    65   12.1 
2025-12-10 00:00 UT   01 11 37.5   +02 52 17     1.771    2.416  119.7   20.7    65   12.1 
2025-12-11 00:00 UT   01 12 00.3   +02 51 45     1.784    2.418  118.8   20.9    65   12.1 
2025-12-12 00:00 UT   01 12 24.5   +02 51 25     1.798    2.420  117.9   21.1    65   12.2 
2025-12-13 00:00 UT   01 12 50.1   +02 51 17     1.811    2.422  116.9   21.2    65   12.2 
2025-12-14 00:00 UT   01 13 17.1   +02 51 22     1.825    2.424  116.0   21.4    66   12.2 
2025-12-15 00:00 UT   01 13 45.4   +02 51 38     1.838    2.426  115.1   21.6    66   12.2 
2025-12-16 00:00 UT   01 14 15.0   +02 52 06     1.852    2.428  114.2   21.7    66   12.3 
2025-12-17 00:00 UT   01 14 45.9   +02 52 45     1.866    2.430  113.3   21.8    66   12.3 

    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.