(101) Helena
ephemeris	date	magn	radius	delta	ra	dec	elong	phase
Opposition	13 May 2025	11.9	2.583 AU	1.595 AU	15h03m	-33°34'	164.4°	6.0°
Today	12 Jul 2025	12.8	2.493 AU	1.881 AU	14h35m	-29°25'	115.4°	21.6°

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)                : 0.1405820
            a (Semimajor axis)              : 2.5835577
            i (Inclination)                 : 10.19186
            Ω (Longitude of ascending node) : 343.36446
            ω (Argument of perihelion)      : 347.78345
            M (Mean anomaly)                : 276.16155
            Epoch                           : 2025 May 05

            L (Longitude of perihelion)     : 331.33502
            B (Latitude of perihelion)      : -2.14582
            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. 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
2025-07-12 00:00 UT   14 35 25.6   -29 25 26     1.881    2.493  115.4   21.6   102   12.8 
2025-07-12 10:05 UT   14 35 35.7   -29 24 16     1.885    2.492  115.1   21.7   102   12.8 
2025-07-13 00:00 UT   14 35 50.2   -29 22 43     1.890    2.491  114.6   21.8   102   12.8 
2025-07-14 00:00 UT   14 36 16.3   -29 20 07     1.900    2.490  113.7   21.9   103   12.8 
2025-07-15 00:00 UT   14 36 44.2   -29 17 38     1.910    2.488  112.9   22.1   103   12.8 
2025-07-16 00:00 UT   14 37 13.7   -29 15 15     1.919    2.487  112.1   22.3   103   12.9 
2025-07-17 00:00 UT   14 37 44.9   -29 13 00     1.929    2.485  111.3   22.4   103   12.9 
2025-07-18 00:00 UT   14 38 17.7   -29 10 52     1.939    2.484  110.4   22.5   103   12.9 
2025-07-19 00:00 UT   14 38 52.1   -29 08 50     1.949    2.482  109.6   22.7   104   12.9 
2025-07-20 00:00 UT   14 39 28.1   -29 06 55     1.959    2.481  108.8   22.8   104   12.9 
2025-07-21 00:00 UT   14 40 05.6   -29 05 07     1.969    2.479  108.0   22.9   104   12.9 
2025-07-22 00:00 UT   14 40 44.7   -29 03 26     1.979    2.478  107.2   23.1   104   12.9 
2025-07-23 00:00 UT   14 41 25.4   -29 01 52     1.989    2.476  106.4   23.2   104   13.0 
2025-07-24 00:00 UT   14 42 07.6   -29 00 24     1.999    2.475  105.6   23.3   104   13.0 
2025-07-25 00:00 UT   14 42 51.3   -28 59 03     2.009    2.473  104.9   23.4   105   13.0 
2025-07-26 00:00 UT   14 43 36.5   -28 57 48     2.020    2.472  104.1   23.5   105   13.0 
2025-07-27 00:00 UT   14 44 23.2   -28 56 40     2.030    2.470  103.3   23.6   105   13.0 
2025-07-28 00:00 UT   14 45 11.3   -28 55 39     2.040    2.469  102.5   23.7   105   13.0 
2025-07-29 00:00 UT   14 46 00.9   -28 54 44     2.051    2.467  101.8   23.8   105   13.0 
2025-07-30 00:00 UT   14 46 51.9   -28 53 55     2.061    2.466  101.0   23.8   105   13.0 
2025-07-31 00:00 UT   14 47 44.2   -28 53 13     2.072    2.464  100.3   23.9   105   13.1 
2025-08-01 00:00 UT   14 48 38.0   -28 52 36     2.082    2.463   99.5   24.0   105   13.1 
2025-08-02 00:00 UT   14 49 33.1   -28 52 06     2.093    2.461   98.8   24.0   106   13.1 
2025-08-03 00:00 UT   14 50 29.6   -28 51 41     2.103    2.460   98.0   24.1   106   13.1 
2025-08-04 00:00 UT   14 51 27.3   -28 51 22     2.114    2.458   97.3   24.2   106   13.1 
2025-08-05 00:00 UT   14 52 26.4   -28 51 09     2.124    2.457   96.6   24.2   106   13.1 
2025-08-06 00:00 UT   14 53 26.8   -28 51 01     2.135    2.455   95.8   24.3   106   13.1 
2025-08-07 00:00 UT   14 54 28.4   -28 50 59     2.146    2.454   95.1   24.3   106   13.1 
2025-08-08 00:00 UT   14 55 31.3   -28 51 02     2.156    2.452   94.4   24.3   106   13.2 
2025-08-09 00:00 UT   14 56 35.4   -28 51 09     2.167    2.451   93.7   24.4   106   13.2 
2025-08-10 00:00 UT   14 57 40.7   -28 51 22     2.178    2.449   93.0   24.4   106   13.2 
2025-08-11 00:00 UT   14 58 47.2   -28 51 40     2.188    2.448   92.3   24.4   106   13.2 

    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.