(101) Helena
ephemeris	date	magn	radius	delta	ra	dec	elong	phase
Today	17 Oct 2025	13.5	2.355 AU	2.844 AU	16h48m	-30°22'	51.4°	19.3°
Opposition	18 Oct 2026	11.3	2.342 AU	1.358 AU	01h17m	+20°59'	168.1°	5.0°

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 Helena are:

            e (Eccentricity)                : 0.1405228
            a (Semimajor axis)              : 2.5836608
            i (Inclination)                 : 10.19192
            Ω (Longitude of ascending node) : 343.35784
            ω (Argument of perihelion)      : 347.75681
            M (Mean anomaly)                : 323.65246
            Epoch                           : 2025 Nov 21

            L (Longitude of perihelion)     : 331.30215
            B (Latitude of perihelion)      : -2.15044
            P (Orbital period in years)     : 4.15            
        

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
2025-10-17 00:00 UT   16 48 23.0   -30 22 35     2.844    2.355   51.4   19.3   103   13.5 
2025-10-17 20:10 UT   16 50 05.5   -30 23 12     2.851    2.354   50.9   19.2   103   13.5 
2025-10-18 00:00 UT   16 50 25.1   -30 23 19     2.852    2.353   50.8   19.2   103   13.5 
2025-10-19 00:00 UT   16 52 27.7   -30 23 60     2.860    2.352   50.3   19.0   103   13.5 
2025-10-20 00:00 UT   16 54 30.7   -30 24 36     2.868    2.351   49.7   18.9   103   13.5 
2025-10-21 00:00 UT   16 56 34.3   -30 25 08     2.876    2.350   49.2   18.7   103   13.5 
2025-10-22 00:00 UT   16 58 38.4   -30 25 37     2.884    2.348   48.7   18.6   103   13.5 
2025-10-23 00:00 UT   17 00 42.9   -30 26 01     2.891    2.347   48.1   18.4   103   13.5 
2025-10-24 00:00 UT   17 02 47.9   -30 26 21     2.899    2.346   47.6   18.2   103   13.5 
2025-10-25 00:00 UT   17 04 53.4   -30 26 36     2.907    2.345   47.0   18.1   103   13.5 
2025-10-26 00:00 UT   17 06 59.3   -30 26 47     2.914    2.343   46.5   17.9   102   13.5 
2025-10-27 00:00 UT   17 09 05.6   -30 26 54     2.921    2.342   46.0   17.8   102   13.5 
2025-10-28 00:00 UT   17 11 12.4   -30 26 55     2.929    2.341   45.4   17.6   102   13.5 
2025-10-29 00:00 UT   17 13 19.6   -30 26 53     2.936    2.340   44.9   17.4   102   13.5 
2025-10-30 00:00 UT   17 15 27.2   -30 26 45     2.943    2.338   44.4   17.3   102   13.5 
2025-10-31 00:00 UT   17 17 35.2   -30 26 32     2.950    2.337   43.8   17.1   102   13.5 
2025-11-01 00:00 UT   17 19 43.5   -30 26 15     2.957    2.336   43.3   16.9   102   13.5 
2025-11-02 00:00 UT   17 21 52.3   -30 25 52     2.964    2.335   42.8   16.8   102   13.5 
2025-11-03 00:00 UT   17 24 01.4   -30 25 24     2.971    2.334   42.2   16.6   102   13.5 
2025-11-04 00:00 UT   17 26 10.9   -30 24 51     2.978    2.332   41.7   16.4   102   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.