51P-A/Harrington
ephemeris	date	magn	radius	delta	ra	dec	elong	phase	PA
Nearest approach	3 Sep 2022	14.0	1.718 AU	0.725 AU	21h54m	-00°00'	164.5°	9.0°	119°
Perihelion	2 Oct 2022	14.1	1.694 AU	0.798 AU	21h57m	-00°11'	140.6°	22.0°	84°
Today	9 Dec 2025	28.9	5.671 AU	5.736 AU	11h36m	-03°08'	81.2°	9.9°	293°

The interactive orbit chart above shows the comet'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.)

Light curve

The light curve chart below shows the estimated development of the comet's magnitude. Blue and black dots are visual and photometric CCD observations from COBS. The light curve is based on the absolute magnitude and slope parameter as calculated from an MPEC, or the latest values provided by the minor planet center. (10.0 + 5 log[∆] + 20.0 log[r]). An additional green curve is displayed when an increase in apparent brightness is expected due to forward scattering of sunlight, which occurs when a dust-rich comet is located between the Earth and the Sun. (See Marcus 2007)

Charts

The all-sky chart below shows the path of the comet over the same period as the light curve. The comet's current position is marked yellow.

The following chart shows the short-term path of the comet in a field of view that is optimized for (~10x50) binoculars and finderscopes.

Orbital elements

The orbital elements of 51P-A/Harrington are:

    e (Eccentricity)                : 0.5428680
    q (Perihelion distance)         : 1.6944220
    i (Inclination)                 : 5.42610
    Ω (Longitude of ascending node) : 269.22740
    ω (Argument of perihelion)      : 83.63140
    L (Longitude of perihelion)     : 352.83037
    B (Latitude of perihelion)      : 5.39252
    T (Time of perihelion passage)  : 2459855.42600
    P (Orbital period in years)     : 7.14

    Epoch                           : 2025 Dec 08
    Reference                       : NK   3014

    Classification(s):              : Ecliptic; Jupiter family
    Tisserand (Jupiter)             : 2.815

Ephemerides

Date       Time       RA (2000)    DEC (2000)    delta   radius  elong  phase   PA    magn
2025-12-08 00:00 UT   11 36 13.8   -03 05 36     5.756    5.670   80.0    9.9   292   28.9 
2025-12-09 00:00 UT   11 36 28.7   -03 08 15     5.741    5.670   81.0    9.9   293   28.9 
2025-12-09 06:32 UT   11 36 32.7   -03 08 58     5.736    5.671   81.2    9.9   293   28.9 
2025-12-10 00:00 UT   11 36 43.0   -03 10 51     5.725    5.671   81.9    9.9   293   28.9 
2025-12-11 00:00 UT   11 36 56.8   -03 13 24     5.709    5.672   82.9    9.9   293   28.9 
2025-12-12 00:00 UT   11 37 10.0   -03 15 53     5.694    5.673   83.8    9.9   293   28.9 
2025-12-13 00:00 UT   11 37 22.5   -03 18 19     5.678    5.673   84.8   10.0   293   28.8 
2025-12-14 00:00 UT   11 37 34.5   -03 20 41     5.662    5.674   85.7   10.0   293   28.8 
2025-12-15 00:00 UT   11 37 45.8   -03 23 00     5.646    5.675   86.7   10.0   293   28.8 
2025-12-16 00:00 UT   11 37 56.5   -03 25 15     5.630    5.675   87.6   10.0   293   28.8 
2025-12-17 00:00 UT   11 38 06.6   -03 27 27     5.614    5.676   88.6   10.0   293   28.8 
2025-12-18 00:00 UT   11 38 16.1   -03 29 35     5.598    5.677   89.5   10.0   293   28.8 
2025-12-19 00:00 UT   11 38 24.9   -03 31 39     5.582    5.677   90.5   10.0   293   28.8 

    Terminology:
            
    delta:  distance between comet and earth in AU
    radius: distance between comet 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-comet)    
    phase:  phase angle in degrees (angle sun-comet-earth)        
    AU:     Astronomical Unit (mean distance between earth and sun: 149597870.7 km      
    

Orbital elements usually provided by the MPC (Minor Planet Center).
Observations contributed by observers worldwide, via COBS (Comet Observation Database) or 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.