C/2020 J1 (SONEAR)
ephemeris	date	magn	radius	delta	ra	dec	elong	phase	PA
Perihelion	17 Apr 2021	12.9	3.344 AU	2.591 AU	16h43m	-36°52'	131.7°	13.0°	291°
Nearest approach	16 May 2021	12.8	3.355 AU	2.355 AU	15h24m	-29°17'	169.7°	3.1°	13°
Today	16 Jan 2026	23.7	13.331 AU	12.562 AU	09h23m	+57°16'	140.0°	2.7°	215°

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)                : 0.9993200
    q (Perihelion distance)         : 3.3438720
    i (Inclination)                 : 142.30950
    Ω (Longitude of ascending node) : 226.56510
    ω (Argument of perihelion)      : 341.53380
    L (Longitude of perihelion)     : 241.36742
    B (Latitude of perihelion)      : -11.16626
    T (Time of perihelion passage)  : 2459322.17440
    P (Orbital period in years)     : 344834.81

    Epoch                           : 2026 Jan 15
    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
2026-01-15 00:00 UT   09 23 51.4   +57 13 33    12.557   13.323  139.8    2.7   217   23.7 
2026-01-16 00:00 UT   09 23 13.7   +57 16 02    12.561   13.329  139.9    2.7   215   23.7 
2026-01-16 07:33 UT   09 23 01.8   +57 16 48    12.562   13.331  140.0    2.7   215   23.7 
2026-01-17 00:00 UT   09 22 35.8   +57 18 27    12.565   13.335  140.1    2.7   213   23.7 
2026-01-18 00:00 UT   09 21 57.5   +57 20 48    12.569   13.340  140.2    2.7   211   23.7 
2026-01-19 00:00 UT   09 21 19.0   +57 23 06    12.574   13.346  140.3    2.7   210   23.7 
2026-01-20 00:00 UT   09 20 40.3   +57 25 20    12.578   13.352  140.4    2.7   208   23.7 
2026-01-21 00:00 UT   09 20 01.3   +57 27 30    12.584   13.358  140.5    2.7   206   23.7 
2026-01-22 00:00 UT   09 19 22.1   +57 29 37    12.589   13.364  140.5    2.7   204   23.7 
2026-01-23 00:00 UT   09 18 42.7   +57 31 40    12.595   13.369  140.5    2.7   202   23.7 
2026-01-24 00:00 UT   09 18 03.1   +57 33 39    12.600   13.375  140.5    2.7   200   23.7 
2026-01-25 00:00 UT   09 17 23.4   +57 35 34    12.607   13.381  140.4    2.7   199   23.7 
2026-01-26 00:00 UT   09 16 43.5   +57 37 26    12.613   13.387  140.4    2.7   197   23.7 

    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.