C/2019 Y1 (ATLAS)
ephemeris	date	magn	radius	delta	ra	dec	elong	phase	PA
Perihelion	17 Mar 2020	8.1	0.826 AU	1.471 AU	00h09m	+30°47'	32.4°	40.2°	10°
Nearest approach	3 May 2020	9.8	1.194 AU	1.092 AU	06h10m	+81°51'	69.1°	52.1°	54°
Today	16 Sep 2025	32.7	16.375 AU	16.958 AU	13h36m	-42°53'	53.1°	2.8°	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.)

The orbital elements of C/2019 Y1 (ATLAS) are:

            e (Eccentricity)                : 0.9906430
            q (Perihelion distance)         : 0.8262500
            i (Inclination)                 : 73.25810
            Ω (Longitude of ascending node) : 31.46290
            ω (Argument of perihelion)      : 57.91890
            L (Longitude of perihelion)     : 56.14381
            B (Latitude of perihelion)      : 54.23118
            T (Time of perihelion passage)  : 2458925.80370
            P (Orbital period in years)     : 829.78

            Epoch                           : 2025 Sep 15
            Reference                       : MPC119999

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

The light curve chart below shows the estimated development of the comet's magnitude. Blue and black dots are visual and photometric CCD observations respectively from COBS or the MPC. The gray curve is based on the absolute magnitude and slope parameter as calculated from the original MPEC, or the latest values provided by the MPC (13.70 + 5 log[∆] + 10.00 log[r]), whereas the red curve is being recalculated every 6 hours based on the available COBS/MPC observations (currently 8.48 + 5 log[∆] + 14.86 log[r]).

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.
A more printer-friendly version of the same chart can be found further down this page as well.

The following chart shows the current location of the comet in a smaller, upside-down telescopic field of view.

A printable version of the short-term path of the comet in a field of view that is optimized for (~10x50) binoculars and finderscopes.

Ephemerides:

Date       Time       RA (2000)    DEC (2000)    delta   radius  elong  phase   PA    magn
2025-09-16 00:00 UT   13 36 09.6   -42 53 39    16.955   16.374   53.3    2.8   141   32.7 
2025-09-16 04:12 UT   13 36 12.2   -42 53 41    16.958   16.375   53.1    2.8   141   32.7 
2025-09-17 00:00 UT   13 36 24.6   -42 53 53    16.971   16.380   52.5    2.8   142   32.7 
2025-09-18 00:00 UT   13 36 39.8   -42 54 08    16.987   16.385   51.8    2.8   142   32.7 
2025-09-19 00:00 UT   13 36 55.1   -42 54 26    17.002   16.391   51.1    2.7   143   32.7 
2025-09-20 00:00 UT   13 37 10.6   -42 54 46    17.018   16.396   50.4    2.7   144   32.7 
2025-09-21 00:00 UT   13 37 26.2   -42 55 09    17.033   16.402   49.7    2.7   145   32.7 
2025-09-22 00:00 UT   13 37 41.8   -42 55 33    17.048   16.407   49.0    2.6   145   32.7 
2025-09-23 00:00 UT   13 37 57.6   -42 55 59    17.063   16.413   48.3    2.6   146   32.7 
2025-09-24 00:00 UT   13 38 13.6   -42 56 27    17.078   16.419   47.6    2.6   147   32.7 
2025-09-25 00:00 UT   13 38 29.6   -42 56 57    17.092   16.424   46.9    2.6   148   32.7 
2025-09-26 00:00 UT   13 38 45.7   -42 57 29    17.106   16.430   46.3    2.5   149   32.7 

    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.