C/2025 J1 (Borisov)
ephemeris	date	magn	radius	delta	ra	dec	elong	phase	PA
Today	30 Oct 2025	18.0	4.108 AU	3.987 AU	11h19m	+70°58'	89.9°	14.0°	317°
Perihelion	11 Jun 2026	17.6	3.581 AU	4.549 AU	06h09m	+33°52'	15.5°	4.3°	49°
Nearest approach	10 Dec 2026	17.2	3.936 AU	3.076 AU	06h24m	-04°42'	146.7°	7.9°	327°

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. This lightcurve is being recalculated every 6 hours based on the available COBS/MPC observations (currently 8.3 + 5 log[∆] + 10.9 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/2025 J1 (Borisov) are:

    e (Eccentricity)                : 0.9969750
    q (Perihelion distance)         : 3.5805370
    i (Inclination)                 : 95.44470
    Ω (Longitude of ascending node) : 273.97650
    ω (Argument of perihelion)      : 166.61890
    L (Longitude of perihelion)     : 275.26954
    B (Latitude of perihelion)      : 13.31961
    T (Time of perihelion passage)  : 2461203.30670
    P (Orbital period in years)     : 40722.48

    Epoch                           : 2025 Oct 29
    Reference                       : MPEC 2025-UQ3

    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
2025-10-29 00:00 UT   11 18 56.1   +70 52 09     4.005    4.113   89.2   14.0   318   18.0 
2025-10-30 00:00 UT   11 19 01.9   +70 57 52     3.990    4.109   89.8   14.0   317   18.0 
2025-10-30 04:35 UT   11 19 02.8   +70 58 59     3.987    4.108   89.9   14.0   317   18.0 
2025-10-31 00:00 UT   11 19 05.7   +71 03 49     3.975    4.104   90.4   14.0   316   18.0 
2025-11-01 00:00 UT   11 19 07.4   +71 10 00     3.960    4.100   91.0   14.0   316   18.0 
2025-11-02 00:00 UT   11 19 06.8   +71 16 25     3.946    4.096   91.6   14.0   315   18.0 
2025-11-03 00:00 UT   11 19 03.9   +71 23 03     3.931    4.092   92.3   14.0   314   18.0 
2025-11-04 00:00 UT   11 18 58.6   +71 29 55     3.916    4.087   92.9   14.0   313   17.9 
2025-11-05 00:00 UT   11 18 50.8   +71 37 01     3.901    4.083   93.5   14.0   312   17.9 
2025-11-06 00:00 UT   11 18 40.3   +71 44 21     3.886    4.079   94.1   14.0   311   17.9 
2025-11-07 00:00 UT   11 18 27.1   +71 51 54     3.872    4.075   94.7   14.0   310   17.9 
2025-11-08 00:00 UT   11 18 11.0   +71 59 40     3.857    4.071   95.3   14.0   309   17.9 
2025-11-09 00:00 UT   11 17 52.0   +72 07 41     3.842    4.066   96.0   14.0   308   17.9 

    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.