(17) Thetis
ephemeris	date	magn	radius	delta	ra	dec	elong	phase
Today	18 Jul 2025	13.6	2.783 AU	3.535 AU	05h13m	+19°13'	36.4°	12.5°
Opposition	30 Dec 2025	11.6	2.777 AU	1.795 AU	06h40m	+19°15'	176.1°	1.4°

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 Thetis are:

            e (Eccentricity)                : 0.1319544
            a (Semimajor axis)              : 2.4711982
            i (Inclination)                 : 5.59242
            Ω (Longitude of ascending node) : 125.52279
            ω (Argument of perihelion)      : 135.78158
            M (Mean anomaly)                : 142.11870
            Epoch                           : 2025 May 05

            L (Longitude of perihelion)     : 81.44099
            B (Latitude of perihelion)      : 3.89694
            P (Orbital period in years)     : 3.88            
        

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
2025-07-18 00:00 UT   05 13 50.6   +19 13 48     3.535    2.783   36.4   12.5   260   13.6 
2025-07-18 22:56 UT   05 15 20.5   +19 15 25     3.528    2.784   36.9   12.7   261   13.6 
2025-07-19 00:00 UT   05 15 24.7   +19 15 30     3.528    2.784   37.0   12.7   261   13.6 
2025-07-20 00:00 UT   05 16 58.5   +19 17 08     3.520    2.784   37.5   12.8   261   13.6 
2025-07-21 00:00 UT   05 18 32.1   +19 18 41     3.512    2.784   38.1   13.0   261   13.6 
2025-07-22 00:00 UT   05 20 05.5   +19 20 11     3.504    2.785   38.7   13.2   261   13.6 
2025-07-23 00:00 UT   05 21 38.6   +19 21 36     3.496    2.785   39.3   13.4   262   13.6 
2025-07-24 00:00 UT   05 23 11.5   +19 22 58     3.488    2.785   39.9   13.5   262   13.6 
2025-07-25 00:00 UT   05 24 44.1   +19 24 15     3.480    2.786   40.5   13.7   262   13.6 
2025-07-26 00:00 UT   05 26 16.4   +19 25 28     3.471    2.786   41.0   13.8   262   13.6 
2025-07-27 00:00 UT   05 27 48.5   +19 26 38     3.462    2.786   41.6   14.0   263   13.6 
2025-07-28 00:00 UT   05 29 20.3   +19 27 43     3.454    2.787   42.2   14.2   263   13.6 
2025-07-29 00:00 UT   05 30 51.7   +19 28 44     3.445    2.787   42.8   14.3   263   13.6 
2025-07-30 00:00 UT   05 32 22.9   +19 29 42     3.436    2.787   43.4   14.5   263   13.6 
2025-07-31 00:00 UT   05 33 53.8   +19 30 35     3.427    2.788   44.0   14.7   263   13.6 
2025-08-01 00:00 UT   05 35 24.4   +19 31 25     3.418    2.788   44.6   14.8   264   13.6 
2025-08-02 00:00 UT   05 36 54.6   +19 32 11     3.409    2.788   45.2   15.0   264   13.6 
2025-08-03 00:00 UT   05 38 24.5   +19 32 53     3.399    2.789   45.8   15.1   264   13.6 
2025-08-04 00:00 UT   05 39 54.1   +19 33 32     3.390    2.789   46.4   15.3   264   13.6 
2025-08-05 00:00 UT   05 41 23.4   +19 34 06     3.380    2.789   47.0   15.4   265   13.6 
2025-08-06 00:00 UT   05 42 52.3   +19 34 37     3.371    2.789   47.6   15.6   265   13.6 
2025-08-07 00:00 UT   05 44 20.9   +19 35 05     3.361    2.790   48.2   15.7   265   13.6 
2025-08-08 00:00 UT   05 45 49.1   +19 35 29     3.351    2.790   48.8   15.9   265   13.6 
2025-08-09 00:00 UT   05 47 16.9   +19 35 49     3.341    2.790   49.4   16.0   265   13.6 
2025-08-10 00:00 UT   05 48 44.4   +19 36 05     3.331    2.790   50.1   16.2   266   13.6 

    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.