C/2021 B2 (PANSTARRS)
ephemeris	date	magn	radius	delta	ra	dec	elong	phase	PA
Nearest approach	15 Dec 2020	20.5	2.926 AU	2.312 AU	03h31m	-29°37'	119.6°	17.0°	32°
Perihelion	4 May 2021	20.5	2.514 AU	3.174 AU	05h38m	+11°28'	41.9°	15.5°	101°
Today	2 May 2025	30.1	12.077 AU	11.292 AU	15h37m	+22°19'	139.6°	3.1°	203°

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)                : 0.9938010
            q (Perihelion distance)         : 2.5144670
            i (Inclination)                 : 38.08630
            Ω (Longitude of ascending node) : 120.44380
            ω (Argument of perihelion)      : 335.10620
            L (Longitude of perihelion)     : 100.37918
            B (Latitude of perihelion)      : -15.04956
            T (Time of perihelion passage)  : 2459339.33160
            P (Orbital period in years)     : 8169.33

            Epoch                           : 2025 May 01
            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
2025-05-02 00:00 UT   15 37 02.4   +22 19 48    11.291   12.076  139.6    3.1   203   30.1 
2025-05-02 02:03 UT   15 37 00.9   +22 19 54    11.292   12.077  139.6    3.1   203   30.1 
2025-05-03 00:00 UT   15 36 44.9   +22 21 03    11.297   12.082  139.6    3.1   201   30.1 
2025-05-04 00:00 UT   15 36 27.3   +22 22 15    11.302   12.089  139.7    3.1   200   30.1 
2025-05-05 00:00 UT   15 36 09.7   +22 23 24    11.308   12.095  139.7    3.1   198   30.1 
2025-05-06 00:00 UT   15 35 52.0   +22 24 29    11.314   12.101  139.7    3.1   197   30.1 
2025-05-07 00:00 UT   15 35 34.2   +22 25 31    11.320   12.107  139.6    3.1   195   30.1 
2025-05-08 00:00 UT   15 35 16.5   +22 26 29    11.327   12.113  139.6    3.1   193   30.1 
2025-05-09 00:00 UT   15 34 58.6   +22 27 23    11.333   12.119  139.5    3.1   192   30.1 
2025-05-10 00:00 UT   15 34 40.8   +22 28 14    11.340   12.126  139.4    3.1   190   30.1 
2025-05-11 00:00 UT   15 34 22.9   +22 29 02    11.348   12.132  139.3    3.1   189   30.1 
2025-05-12 00:00 UT   15 34 05.0   +22 29 46    11.355   12.138  139.2    3.1   187   30.1 

    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.