C/2021 P2 (PANSTARRS)
ephemeris	date	magn	radius	delta	ra	dec	elong	phase	PA
Nearest approach	2 Sep 2022	19.3	5.182 AU	4.295 AU	21h42m	+19°35'	148.5°	5.8°	150°
Perihelion	23 Jan 2023	19.9	5.067 AU	5.921 AU	20h40m	+07°07'	27.3°	5.1°	11°
Today	24 Dec 2025	23.6	9.141 AU	9.870 AU	15h32m	-09°56'	40.3°	4.0°	295°

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. (9.0 + 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/2021 P2 (PANSTARRS) are:

    e (Eccentricity)                : 0.9996140
    q (Perihelion distance)         : 5.0665030
    i (Inclination)                 : 150.04840
    Ω (Longitude of ascending node) : 32.10030
    ω (Argument of perihelion)      : 76.70070
    L (Longitude of perihelion)     : -42.64007
    B (Latitude of perihelion)      : 29.07006
    T (Time of perihelion passage)  : 2459967.52570

    Epoch                           : 2025 Dec 23
    Reference                       : MPC185656

    Classification(s):              : Nearly isotropic; New (a > 10000 AU)

Ephemerides

Date       Time       RA (2000)    DEC (2000)    delta   radius  elong  phase   PA    magn
2025-12-23 00:00 UT   15 31 48.0   -09 55 14     9.878    9.133   38.8    3.9   295   23.6 
2025-12-24 00:00 UT   15 31 58.7   -09 56 15     9.873    9.139   39.8    3.9   295   23.6 
2025-12-24 12:12 UT   15 32 04.0   -09 56 46     9.870    9.141   40.3    4.0   295   23.6 
2025-12-25 00:00 UT   15 32 09.1   -09 57 15     9.867    9.144   40.7    4.0   294   23.6 
2025-12-26 00:00 UT   15 32 19.2   -09 58 14     9.861    9.149   41.7    4.1   294   23.6 
2025-12-27 00:00 UT   15 32 29.1   -09 59 11     9.854    9.155   42.6    4.2   294   23.6 
2025-12-28 00:00 UT   15 32 38.7   -10 00 06     9.847    9.160   43.6    4.2   293   23.6 
2025-12-29 00:00 UT   15 32 48.1   -10 00 59     9.841    9.166   44.5    4.3   293   23.6 
2025-12-30 00:00 UT   15 32 57.2   -10 01 50     9.833    9.171   45.5    4.4   293   23.6 
2025-12-31 00:00 UT   15 33 06.1   -10 02 40     9.826    9.176   46.4    4.5   292   23.6 
2026-01-01 00:00 UT   15 33 14.6   -10 03 29     9.819    9.182   47.4    4.5   292   23.6 
2026-01-02 00:00 UT   15 33 22.9   -10 04 15     9.811    9.187   48.3    4.6   292   23.6 
2026-01-03 00:00 UT   15 33 30.9   -10 04 60     9.803    9.192   49.3    4.7   292   23.6 

    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.