C/2021 J2 (PANSTARRS)
ephemeris	date	magn	radius	delta	ra	dec	elong	phase	PA
Nearest approach	12 May 2021	21.7	4.810 AU	3.823 AU	15h06m	-04°23'	166.0°	2.9°	170°
Perihelion	19 Sep 2021	22.5	4.703 AU	5.563 AU	13h36m	-07°04'	28.4°	5.8°	106°
Today	5 Nov 2026	28.8	13.254 AU	12.814 AU	06h58m	-01°35'	114.4°	3.9°	288°

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. (12.0 + 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 J2 (PANSTARRS) are:

    e (Eccentricity)                : 0.9570400
    q (Perihelion distance)         : 4.7029490
    i (Inclination)                 : 156.21250
    Ω (Longitude of ascending node) : 23.28260
    ω (Argument of perihelion)      : 171.83980
    L (Longitude of perihelion)     : 30.75777
    B (Latitude of perihelion)      : 3.28206
    T (Time of perihelion passage)  : 2459477.25880
    P (Orbital period in years)     : 1145.40

    Epoch                           : 2026 May 29
    Reference                       : MPC194174

    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
2026-11-04 00:00 UT   06 58 48.7   -01 33 18    12.830   13.245  112.7    4.0   287   28.8 
2026-11-05 00:00 UT   06 58 35.2   -01 34 34    12.821   13.250  113.7    3.9   288   28.8 
2026-11-05 17:36 UT   06 58 25.1   -01 35 29    12.814   13.254  114.4    3.9   288   28.8 
2026-11-06 00:00 UT   06 58 21.4   -01 35 49    12.811   13.256  114.6    3.9   288   28.8 
2026-11-07 00:00 UT   06 58 07.3   -01 37 03    12.802   13.261  115.6    3.9   289   28.8 
2026-11-08 00:00 UT   06 57 52.9   -01 38 15    12.794   13.266  116.5    3.8   289   28.8 
2026-11-09 00:00 UT   06 57 38.2   -01 39 26    12.785   13.271  117.4    3.8   290   28.8 
2026-11-10 00:00 UT   06 57 23.2   -01 40 36    12.776   13.276  118.4    3.8   290   28.8 
2026-11-11 00:00 UT   06 57 07.9   -01 41 44    12.768   13.281  119.3    3.7   291   28.8 
2026-11-12 00:00 UT   06 56 52.3   -01 42 51    12.759   13.286  120.3    3.7   291   28.8 
2026-11-13 00:00 UT   06 56 36.5   -01 43 57    12.751   13.292  121.2    3.7   292   28.8 
2026-11-14 00:00 UT   06 56 20.3   -01 45 00    12.743   13.297  122.1    3.6   293   28.8 
2026-11-15 00:00 UT   06 56 03.9   -01 46 03    12.736   13.302  123.1    3.6   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.