C/2019 Y1 (ATLAS)
ephemeris date magn radius delta ra dec elong phase PA
Perihelion17 Mar 20208.10.826 AU1.471 AU00h09m+30°47'32.4°40.2°10°
Nearest approach3 May 20209.81.194 AU1.093 AU06h10m+81°49'69.1°52.1°54°
Today17 Oct 202532.816.551 AU17.367 AU13h44m-43°17'34.0°1.9°173°
C/2019 Y1 (ATLAS)- 2025-10-17
astro.vanbuitenen.nl


 
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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 8.5 + 5 log[∆] + 14.9 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/2019 Y1 (ATLAS) are:

    e (Eccentricity)                : 0.9906480
    q (Perihelion distance)         : 0.8262440
    i (Inclination)                 : 73.24730
    Ω (Longitude of ascending node) : 31.45560
    ω (Argument of perihelion)      : 57.92150
    L (Longitude of perihelion)     : 56.15233
    B (Latitude of perihelion)      : 54.22893
    T (Time of perihelion passage)  : 2458925.83650
    P (Orbital period in years)     : 830.44

    Epoch                           : 2025 Oct 16
    Reference                       : MPC119999

    Classification(s):              : Nearly isotropic; Returning (a < 10000 AU); External (P > 200 years); Liller

Ephemerides

Date       Time       RA (2000)    DEC (2000)    delta   radius  elong  phase   PA    magn
2025-10-16 00:00 UT   13 44 23.8   -43 14 56    17.349   16.541   34.8    2.0   171   32.8 
2025-10-17 00:00 UT   13 44 41.2   -43 16 08    17.359   16.546   34.4    1.9   172   32.8 
2025-10-17 19:49 UT   13 44 55.6   -43 17 08    17.367   16.551   34.0    1.9   173   32.8 
2025-10-18 00:00 UT   13 44 58.6   -43 17 21    17.369   16.552   33.9    1.9   174   32.8 
2025-10-19 00:00 UT   13 45 16.1   -43 18 36    17.378   16.557   33.5    1.9   175   32.8 
2025-10-20 00:00 UT   13 45 33.5   -43 19 53    17.387   16.563   33.1    1.9   177   32.8 
2025-10-21 00:00 UT   13 45 50.9   -43 21 12    17.396   16.568   32.8    1.9   178   32.8 
2025-10-22 00:00 UT   13 46 08.4   -43 22 32    17.405   16.574   32.4    1.8   180   32.8 
2025-10-23 00:00 UT   13 46 25.8   -43 23 54    17.413   16.579   32.1    1.8   181   32.8 
2025-10-24 00:00 UT   13 46 43.2   -43 25 17    17.421   16.585   31.8    1.8   183   32.8 
2025-10-25 00:00 UT   13 47 00.6   -43 26 42    17.429   16.590   31.5    1.8   185   32.8 
2025-10-26 00:00 UT   13 47 18.0   -43 28 09    17.437   16.596   31.3    1.8   187   32.8 
2025-10-27 00:00 UT   13 47 35.4   -43 29 37    17.445   16.601   31.0    1.8   188   32.8 



    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.