C/2021 B2 (PANSTARRS)
ephemeris	date	magn	radius	delta	ra	dec	elong	phase	PA
Nearest approach	15 Dec 2020	20.5	2.927 AU	2.313 AU	03h31m	-29°37'	119.6°	17.0°	32°
Perihelion	4 May 2021	20.5	2.515 AU	3.174 AU	05h39m	+11°28'	41.9°	15.5°	101°
Today	5 Jul 2025	30.4	12.473 AU	12.076 AU	15h20m	+21°41'	110.7°	4.4°	127°

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.)

The orbital elements of C/2021 B2 (PANSTARRS) are:

            e (Eccentricity)                : 0.9938480
            q (Perihelion distance)         : 2.5150150
            i (Inclination)                 : 38.08700
            Ω (Longitude of ascending node) : 120.43820
            ω (Argument of perihelion)      : 335.11970
            L (Longitude of perihelion)     : 100.38515
            B (Latitude of perihelion)      : -15.04198
            T (Time of perihelion passage)  : 2459339.34990
            P (Orbital period in years)     : 8265.83

            Epoch                           : 2025 Jul 04
            Reference                       : MPEC 2022-L66

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

The light curve chart below shows the estimated development of the comet's magnitude. Blue and black dots are visual and photometric CCD observations respectively from COBS or the MPC. 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. (14.00 + 5 log[∆] + 10.00 log[r]).

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.
A more printer-friendly version of the same chart can be found further down this page as well.

The following chart shows the current location of the comet in a smaller, upside-down telescopic field of view.

A printable version of the short-term path of the comet in a field of view that is optimized for (~10x50) binoculars and finderscopes.

Ephemerides:

Date       Time       RA (2000)    DEC (2000)    delta   radius  elong  phase   PA    magn
2025-07-05 00:00 UT   15 20 45.3   +21 43 01    12.064   12.469  111.2    4.4   127   30.4 
2025-07-05 16:03 UT   15 20 39.4   +21 41 30    12.076   12.473  110.7    4.4   127   30.4 
2025-07-06 00:00 UT   15 20 36.5   +21 40 45    12.082   12.475  110.5    4.4   126   30.4 
2025-07-07 00:00 UT   15 20 28.0   +21 38 27    12.100   12.481  109.8    4.4   126   30.4 
2025-07-08 00:00 UT   15 20 19.8   +21 36 06    12.118   12.487  109.1    4.4   125   30.4 
2025-07-09 00:00 UT   15 20 11.9   +21 33 44    12.136   12.493  108.3    4.4   124   30.4 
2025-07-10 00:00 UT   15 20 04.3   +21 31 19    12.154   12.499  107.6    4.4   124   30.4 
2025-07-11 00:00 UT   15 19 57.0   +21 28 52    12.172   12.505  106.9    4.5   123   30.4 
2025-07-12 00:00 UT   15 19 50.0   +21 26 23    12.190   12.512  106.2    4.5   122   30.4 
2025-07-13 00:00 UT   15 19 43.3   +21 23 52    12.208   12.518  105.4    4.5   122   30.4 
2025-07-14 00:00 UT   15 19 36.9   +21 21 19    12.227   12.524  104.7    4.5   121   30.4 
2025-07-15 00:00 UT   15 19 30.8   +21 18 44    12.245   12.530  104.0    4.5   120   30.4 

    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.