C/2021 L3 (Borisov)
ephemeris	date	magn	radius	delta	ra	dec	elong	phase	PA
Nearest approach	23 Nov 2021	19.9	8.473 AU	8.327 AU	18h33m	+70°44'	95.2°	6.7°	36°
Perihelion	14 Feb 2022	19.9	8.459 AU	8.425 AU	19h36m	+72°51'	88.6°	6.7°	327°
Today	26 Apr 2024	20.7	9.675 AU	9.409 AU	11h33m	+56°04'	102.4°	5.8°	140°

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 L3 (Borisov) are:

            e (Eccentricity)                : 1.0044390
            q (Perihelion distance)         : 8.4586440
            i (Inclination)                 : 78.56450
            Ω (Longitude of ascending node) : 344.99560
            ω (Argument of perihelion)      : 91.63090
            L (Longitude of perihelion)     : 263.16782
            B (Latitude of perihelion)      : 78.45032
            T (Time of perihelion passage)  : 2459625.14060

            Epoch                           : 2024 Apr 25
            Reference                       : MPEC 2024-H50

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

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. (6.00 + 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
2024-04-26 00:00 UT   11 33 46.3   +56 07 36     9.402    9.674  102.7    5.8   140   20.7 
2024-04-26 12:48 UT   11 33 28.0   +56 04 57     9.409    9.675  102.4    5.8   140   20.7 
2024-04-27 00:00 UT   11 33 12.1   +56 02 37     9.415    9.676  102.1    5.8   139   20.7 
2024-04-28 00:00 UT   11 32 38.7   +55 57 33     9.428    9.679  101.5    5.9   138   20.7 
2024-04-29 00:00 UT   11 32 05.9   +55 52 26     9.442    9.682  100.8    5.9   137   20.7 
2024-04-30 00:00 UT   11 31 34.0   +55 47 14     9.455    9.685  100.2    5.9   136   20.7 
2024-05-01 00:00 UT   11 31 02.7   +55 41 57     9.469    9.687   99.6    5.9   136   20.7 
2024-05-02 00:00 UT   11 30 32.2   +55 36 37     9.482    9.690   98.9    5.9   135   20.7 
2024-05-03 00:00 UT   11 30 02.5   +55 31 13     9.496    9.693   98.3    5.9   134   20.8 
2024-05-04 00:00 UT   11 29 33.5   +55 25 45     9.510    9.696   97.6    5.9   133   20.8 
2024-05-05 00:00 UT   11 29 05.2   +55 20 13     9.524    9.699   97.0    5.9   132   20.8 
2024-05-06 00:00 UT   11 28 37.7   +55 14 38     9.538    9.701   96.3    5.9   131   20.8 

    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.