C/2019 Y1 (ATLAS)
ephemeris	date	magn	radius	delta	ra	dec	elong	phase	PA
Perihelion	17 Mar 2020	8.1	0.832 AU	1.481 AU	00h10m	+30°43'	32.3°	39.7°	10°
Nearest approach	3 May 2020	9.9	1.196 AU	1.112 AU	05h51m	+81°37'	68.5°	51.7°	49°
Today	17 Mar 2026	33.2	17.627 AU	17.044 AU	13h55m	-46°41'	124.5°	2.7°	320°

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)                : 0.9966800
    q (Perihelion distance)         : 0.8322620
    i (Inclination)                 : 73.26730
    Ω (Longitude of ascending node) : 31.28250
    ω (Argument of perihelion)      : 57.44230
    L (Longitude of perihelion)     : 55.55411
    B (Latitude of perihelion)      : 53.81960
    T (Time of perihelion passage)  : 2458925.94540
    P (Orbital period in years)     : 3969.02

    Epoch                           : 2026 Mar 16
    Reference                       : MPEC 2026-E44

    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
2026-03-16 00:00 UT   13 55 37.8   -46 40 15    17.054   17.618  123.2    2.7   319   33.2 
2026-03-17 00:00 UT   13 55 22.1   -46 40 51    17.048   17.624  124.0    2.7   320   33.2 
2026-03-17 16:22 UT   13 55 11.4   -46 41 13    17.044   17.627  124.5    2.7   320   33.2 
2026-03-18 00:00 UT   13 55 06.3   -46 41 24    17.043   17.629  124.7    2.7   321   33.2 
2026-03-19 00:00 UT   13 54 50.3   -46 41 55    17.037   17.635  125.5    2.6   321   33.2 
2026-03-20 00:00 UT   13 54 34.0   -46 42 23    17.032   17.640  126.3    2.6   322   33.2 
2026-03-21 00:00 UT   13 54 17.6   -46 42 49    17.027   17.646  127.0    2.6   323   33.2 
2026-03-22 00:00 UT   13 54 01.0   -46 43 12    17.023   17.651  127.8    2.6   324   33.2 
2026-03-23 00:00 UT   13 53 44.3   -46 43 33    17.018   17.657  128.5    2.5   325   33.2 
2026-03-24 00:00 UT   13 53 27.3   -46 43 52    17.014   17.663  129.3    2.5   326   33.2 
2026-03-25 00:00 UT   13 53 10.2   -46 44 08    17.010   17.668  130.0    2.5   327   33.2 
2026-03-26 00:00 UT   13 52 52.9   -46 44 21    17.006   17.674  130.7    2.5   328   33.2 
2026-03-27 00:00 UT   13 52 35.5   -46 44 32    17.002   17.679  131.4    2.4   329   33.2 

    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.