(85) Io
ephemeris	date	magn	radius	delta	ra	dec	elong	phase
Today	23 May 2026	13.4	2.750 AU	3.725 AU	04h49m	+15°13'	13.3°	4.9°
Opposition	22 Jan 2027	12.5	3.102 AU	2.148 AU	08h03m	+02°50'	162.8°	5.4°

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 Io are:

            e (Eccentricity)                : 0.1930854
            a (Semimajor axis)              : 2.6530325
            i (Inclination)                 : 11.96083
            Ω (Longitude of ascending node) : 203.04208
            ω (Argument of perihelion)      : 122.89556
            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
2026-05-23 00:00 UT   04 49 05.3   +15 13 47     3.725    2.750   13.3    4.9   115   13.4 
2026-05-23 15:12 UT   04 50 09.6   +15 15 07     3.728    2.751   13.0    4.8   116   13.4 
2026-05-24 00:00 UT   04 50 46.9   +15 15 52     3.730    2.752   12.8    4.7   117   13.4 
2026-05-25 00:00 UT   04 52 28.5   +15 17 52     3.734    2.754   12.4    4.5   118   13.4 
2026-05-26 00:00 UT   04 54 10.2   +15 19 48     3.738    2.755   12.0    4.4   120   13.4 
2026-05-27 00:00 UT   04 55 51.8   +15 21 39     3.742    2.757   11.6    4.2   122   13.4 
2026-05-28 00:00 UT   04 57 33.3   +15 23 25     3.746    2.759   11.1    4.1   124   13.4 
2026-05-29 00:00 UT   04 59 14.9   +15 25 06     3.750    2.761   10.7    3.9   126   13.4 
2026-05-30 00:00 UT   05 00 56.4   +15 26 43     3.754    2.763   10.4    3.8   128   13.4 
2026-05-31 00:00 UT   05 02 37.9   +15 28 15     3.758    2.765   10.0    3.6   131   13.4 
2026-06-01 00:00 UT   05 04 19.4   +15 29 42     3.761    2.767    9.6    3.5   133   13.4 
2026-06-02 00:00 UT   05 06 00.8   +15 31 05     3.765    2.769    9.3    3.4   136   13.4 
2026-06-03 00:00 UT   05 07 42.2   +15 32 22     3.768    2.771    9.0    3.3   139   13.3 
2026-06-04 00:00 UT   05 09 23.6   +15 33 35     3.771    2.773    8.7    3.2   142   13.3 
2026-06-05 00:00 UT   05 11 04.9   +15 34 43     3.774    2.775    8.4    3.1   146   13.3 
2026-06-06 00:00 UT   05 12 46.1   +15 35 47     3.777    2.776    8.2    3.0   149   13.3 
2026-06-07 00:00 UT   05 14 27.3   +15 36 45     3.780    2.778    8.0    2.9   153   13.3 
2026-06-08 00:00 UT   05 16 08.5   +15 37 39     3.782    2.780    7.8    2.8   157   13.3 
2026-06-09 00:00 UT   05 17 49.5   +15 38 28     3.785    2.782    7.7    2.8   161   13.3 
2026-06-10 00:00 UT   05 19 30.6   +15 39 12     3.787    2.784    7.6    2.8   165   13.3 
2026-06-11 00:00 UT   05 21 11.5   +15 39 51     3.789    2.786    7.5    2.7   170   13.3 
2026-06-12 00:00 UT   05 22 52.4   +15 40 26     3.791    2.788    7.5    2.7   174   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.