C/2020 J1 (SONEAR)
ephemeris	date	magn	radius	delta	ra	dec	elong	phase	PA
Perihelion	17 Apr 2021	12.9	3.344 AU	2.590 AU	16h43m	-36°51'	131.8°	12.9°	291°
Nearest approach	16 May 2021	12.8	3.355 AU	2.355 AU	15h24m	-29°18'	169.7°	3.1°	13°
Today	23 Nov 2025	23.6	13.022 AU	12.680 AU	09h45m	+54°18'	108.2°	4.1°	280°

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 4.5 + 5 log[∆] + 12.2 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/2020 J1 (SONEAR) are:

    e (Eccentricity)                : 0.9994060
    q (Perihelion distance)         : 3.3440520
    i (Inclination)                 : 142.30870
    Ω (Longitude of ascending node) : 226.57140
    ω (Argument of perihelion)      : 341.54480
    L (Longitude of perihelion)     : 241.36452
    B (Latitude of perihelion)      : -11.15996
    T (Time of perihelion passage)  : 2459322.28330
    P (Orbital period in years)     : 422405.79

    Epoch                           : 2025 Nov 23
    Reference                       : MPEC 2023-KD6

    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
2025-11-22 00:00 UT   09 46 13.3   +54 11 58    12.693   13.011  106.6    4.2   281   23.6 
2025-11-23 00:00 UT   09 46 03.2   +54 15 30    12.686   13.017  107.4    4.2   281   23.6 
2025-11-23 22:03 UT   09 45 53.3   +54 18 46    12.680   13.022  108.2    4.1   280   23.6 
2025-11-24 00:00 UT   09 45 52.4   +54 19 03    12.679   13.022  108.2    4.1   280   23.6 
2025-11-25 00:00 UT   09 45 41.1   +54 22 37    12.672   13.028  109.0    4.1   279   23.6 
2025-11-26 00:00 UT   09 45 29.2   +54 26 12    12.665   13.034  109.8    4.1   278   23.6 
2025-11-27 00:00 UT   09 45 16.8   +54 29 48    12.659   13.040  110.6    4.1   278   23.6 
2025-11-28 00:00 UT   09 45 03.8   +54 33 24    12.652   13.046  111.4    4.0   277   23.6 
2025-11-29 00:00 UT   09 44 50.1   +54 37 01    12.646   13.051  112.2    4.0   276   23.6 
2025-11-30 00:00 UT   09 44 36.0   +54 40 39    12.639   13.057  113.0    4.0   275   23.6 
2025-12-01 00:00 UT   09 44 21.2   +54 44 17    12.633   13.063  113.8    4.0   274   23.6 
2025-12-02 00:00 UT   09 44 05.8   +54 47 56    12.627   13.069  114.6    3.9   274   23.6 
2025-12-03 00:00 UT   09 43 49.9   +54 51 35    12.621   13.075  115.4    3.9   273   23.6 

    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.