C/2025 B2 (Borisov)
ephemeris	date	magn	radius	delta	ra	dec	elong	phase	PA
Today	17 Jun 2025	20.4	8.670 AU	9.314 AU	05h02m	+71°12'	48.2°	5.0°	347°
Nearest approach	14 Dec 2025	20.0	8.401 AU	8.003 AU	21h07m	+85°38'	110.7°	6.3°	53°
Perihelion	9 Sep 2026	20.0	8.245 AU	8.303 AU	16h36m	+78°27'	83.2°	7.0°	82°

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/2025 B2 (Borisov) are:

            e (Eccentricity)                : 1.0000650
            q (Perihelion distance)         : 8.2448630
            i (Inclination)                 : 91.75170
            Ω (Longitude of ascending node) : 84.87340
            ω (Argument of perihelion)      : 78.72880
            L (Longitude of perihelion)     : 76.15333
            B (Latitude of perihelion)      : 78.59523
            T (Time of perihelion passage)  : 2461293.49560

            Epoch                           : 2025 Jun 16
            Reference                       : MPC184414

            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. (6.20 + 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
2025-06-17 00:00 UT   05 02 03.2   +71 10 28     9.316    8.671   48.1    5.0   348   20.4 
2025-06-17 10:36 UT   05 02 33.8   +71 12 14     9.314    8.670   48.2    5.0   347   20.4 
2025-06-18 00:00 UT   05 03 12.6   +71 14 28     9.313    8.669   48.2    5.0   347   20.4 
2025-06-19 00:00 UT   05 04 22.4   +71 18 31     9.309    8.667   48.3    5.0   346   20.4 
2025-06-20 00:00 UT   05 05 32.4   +71 22 37     9.306    8.665   48.4    5.0   345   20.4 
2025-06-21 00:00 UT   05 06 42.7   +71 26 46     9.302    8.664   48.6    5.0   344   20.4 
2025-06-22 00:00 UT   05 07 53.4   +71 30 58     9.299    8.662   48.7    5.1   343   20.4 
2025-06-23 00:00 UT   05 09 04.3   +71 35 13     9.295    8.660   48.8    5.1   342   20.4 
2025-06-24 00:00 UT   05 10 15.6   +71 39 32     9.291    8.658   49.0    5.1   342   20.4 
2025-06-25 00:00 UT   05 11 27.1   +71 43 54     9.287    8.656   49.2    5.1   341   20.4 
2025-06-26 00:00 UT   05 12 38.9   +71 48 19     9.282    8.654   49.3    5.1   340   20.4 
2025-06-27 00:00 UT   05 13 51.0   +71 52 47     9.278    8.653   49.5    5.1   339   20.4 

    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.