C/2019 J3 (ATLAS)
ephemeris	date	magn	radius	delta	ra	dec	elong	phase	PA
Nearest approach	24 Jun 2019	18.0	2.399 AU	1.385 AU	17h48m	-20°56'	174.5°	2.3°	118°
Perihelion	1 Aug 2019	18.6	2.360 AU	1.882 AU	15h43m	-03°51'	105.2°	24.5°	108°
Today	23 Dec 2025	32.0	17.315 AU	16.437 AU	07h44m	+42°34'	152.3°	1.5°	234°

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. 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. (13.5 + 5 log[∆] + 10.0 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/2019 J3 (ATLAS) are:

    e (Eccentricity)                : 0.9997150
    q (Perihelion distance)         : 2.3603330
    i (Inclination)                 : 131.29340
    Ω (Longitude of ascending node) : 270.65580
    ω (Argument of perihelion)      : 16.46630
    L (Longitude of perihelion)     : 259.61863
    B (Latitude of perihelion)      : 12.29636
    T (Time of perihelion passage)  : 2458697.08860
    P (Orbital period in years)     : 753689.78

    Epoch                           : 2025 Nov 12
    Reference                       : MPC117071

    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
2025-12-22 00:00 UT   07 44 34.8   +42 33 04    16.437   17.306  151.1    1.6   237   32.0 
2025-12-23 00:00 UT   07 44 14.7   +42 33 52    16.437   17.311  151.9    1.5   235   32.0 
2025-12-23 15:00 UT   07 44 02.0   +42 34 22    16.437   17.315  152.3    1.5   234   32.0 
2025-12-24 00:00 UT   07 43 54.4   +42 34 39    16.437   17.317  152.6    1.5   233   32.0 
2025-12-25 00:00 UT   07 43 34.1   +42 35 25    16.438   17.322  153.2    1.5   231   32.0 
2025-12-26 00:00 UT   07 43 13.5   +42 36 09    16.439   17.328  153.9    1.4   229   32.0 
2025-12-27 00:00 UT   07 42 52.9   +42 36 52    16.440   17.333  154.5    1.4   227   32.0 
2025-12-28 00:00 UT   07 42 32.2   +42 37 34    16.441   17.338  155.1    1.4   225   32.0 
2025-12-29 00:00 UT   07 42 11.3   +42 38 14    16.443   17.344  155.6    1.3   223   32.0 
2025-12-30 00:00 UT   07 41 50.4   +42 38 53    16.445   17.349  156.2    1.3   220   32.0 
2025-12-31 00:00 UT   07 41 29.3   +42 39 31    16.447   17.355  156.7    1.3   218   32.0 
2026-01-01 00:00 UT   07 41 08.2   +42 40 07    16.449   17.360  157.1    1.3   215   32.0 
2026-01-02 00:00 UT   07 40 47.0   +42 40 41    16.452   17.366  157.5    1.2   213   32.0 

    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.