C/2019 T3 (ATLAS)
ephemeris	date	magn	radius	delta	ra	dec	elong	phase	PA
Perihelion	5 Mar 2021	16.6	5.953 AU	6.552 AU	22h50m	+43°00'	49.2°	7.3°	356°
Nearest approach	11 Sep 2021	16.3	6.101 AU	5.373 AU	22h03m	+39°32'	132.7°	7.0°	155°
Today	16 Jan 2026	21.6	12.827 AU	13.731 AU	20h50m	-39°22'	22.4°	1.7°	141°

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 4.8 + 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 T3 (ATLAS) are:

    e (Eccentricity)                : 0.9989760
    q (Perihelion distance)         : 5.9526640
    i (Inclination)                 : 121.88660
    Ω (Longitude of ascending node) : 139.54990
    ω (Argument of perihelion)      : 112.49240
    L (Longitude of perihelion)     : 191.45895
    B (Latitude of perihelion)      : 51.67490
    T (Time of perihelion passage)  : 2459278.50740
    P (Orbital period in years)     : 443217.72

    Epoch                           : 2026 Jan 15
    Reference                       : MPEC 2023-UR6

    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   20 49 53.3   -39 23 19    13.722   12.821   22.8    1.7   138   21.6 
2026-01-16 00:00 UT   20 50 12.6   -39 22 57    13.730   12.826   22.4    1.7   140   21.6 
2026-01-16 03:17 UT   20 50 15.2   -39 22 54    13.731   12.827   22.4    1.7   141   21.6 
2026-01-17 00:00 UT   20 50 31.9   -39 22 37    13.737   12.831   22.1    1.7   143   21.6 
2026-01-18 00:00 UT   20 50 51.4   -39 22 18    13.744   12.836   21.8    1.6   145   21.6 
2026-01-19 00:00 UT   20 51 10.9   -39 22 01    13.751   12.841   21.6    1.6   148   21.6 
2026-01-20 00:00 UT   20 51 30.4   -39 21 44    13.757   12.846   21.4    1.6   150   21.6 
2026-01-21 00:00 UT   20 51 50.0   -39 21 29    13.763   12.851   21.2    1.6   153   21.6 
2026-01-22 00:00 UT   20 52 09.7   -39 21 15    13.769   12.856   21.1    1.6   155   21.6 
2026-01-23 00:00 UT   20 52 29.4   -39 21 03    13.775   12.861   21.0    1.6   158   21.6 
2026-01-24 00:00 UT   20 52 49.1   -39 20 51    13.780   12.866   21.0    1.6   161   21.6 
2026-01-25 00:00 UT   20 53 08.8   -39 20 41    13.785   12.871   21.0    1.6   163   21.6 
2026-01-26 00:00 UT   20 53 28.6   -39 20 33    13.790   12.876   21.0    1.6   166   21.6 

    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.