C/2011 L4 (PANSTARRS)
ephemeris	date	magn	radius	delta	ra	dec	elong	phase	PA
Nearest approach	4 Mar 2013	0.7	0.320 AU	1.089 AU	23h55m	-16°05'	16.9°	64.0°	123°
Perihelion	8 Mar 2013	0.4	0.296 AU	1.098 AU	00h14m	-05°54'	15.3°	61.8°	93°
Today	19 Feb 2026	27.8	30.660 AU	30.687 AU	16h33m	+15°59'	87.4°	1.8°	283°

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. (5.5 + 5 log[∆] + 10.0 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 C/2011 L4 (PANSTARRS) are:

    e (Eccentricity)                : 0.9998370
    q (Perihelion distance)         : 0.2963480
    i (Inclination)                 : 84.04880
    Ω (Longitude of ascending node) : 65.86430
    ω (Argument of perihelion)      : 333.47960
    L (Longitude of perihelion)     : 62.90247
    B (Latitude of perihelion)      : -26.36641
    T (Time of perihelion passage)  : 2456359.52500
    P (Orbital period in years)     : 77521.40

    Epoch                           : 2020 Sep 26
    Reference                       : MPC115880

    Classification(s):              : Nearly isotropic; Returning (a < 10000 AU); External (P > 200 years)

Ephemerides

Date       Time       RA (2000)    DEC (2000)    delta   radius  elong  phase   PA    magn
2026-02-18 00:00 UT   16 33 49.6   +15 58 00    30.700   30.654   86.3    1.8   283   27.8 
2026-02-19 00:00 UT   16 33 51.1   +15 59 05    30.691   30.658   87.1    1.8   283   27.8 
2026-02-19 09:19 UT   16 33 51.6   +15 59 31    30.687   30.660   87.4    1.8   283   27.8 
2026-02-20 00:00 UT   16 33 52.5   +16 00 11    30.682   30.662   87.9    1.8   282   27.8 
2026-02-21 00:00 UT   16 33 53.7   +16 01 17    30.672   30.667   88.7    1.8   282   27.8 
2026-02-22 00:00 UT   16 33 54.7   +16 02 24    30.663   30.671   89.5    1.8   281   27.8 
2026-02-23 00:00 UT   16 33 55.7   +16 03 31    30.653   30.676   90.3    1.8   280   27.8 
2026-02-24 00:00 UT   16 33 56.5   +16 04 38    30.644   30.680   91.1    1.8   280   27.8 
2026-02-25 00:00 UT   16 33 57.2   +16 05 46    30.634   30.684   91.9    1.8   279   27.8 
2026-02-26 00:00 UT   16 33 57.7   +16 06 54    30.625   30.689   92.7    1.8   279   27.8 
2026-02-27 00:00 UT   16 33 58.1   +16 08 03    30.616   30.693   93.5    1.8   278   27.8 
2026-02-28 00:00 UT   16 33 58.3   +16 09 12    30.606   30.697   94.3    1.8   277   27.8 
2026-03-01 00:00 UT   16 33 58.4   +16 10 21    30.597   30.702   95.1    1.8   277   27.8 

    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.