C/2020 X2 (ATLAS)
ephemeris	date	magn	radius	delta	ra	dec	elong	phase	PA
Perihelion	17 Nov 2020	18.9	3.835 AU	3.124 AU	07h02m	+17°54'	130.0°	11.4°	280°
Nearest approach	30 Dec 2020	18.7	3.850 AU	2.867 AU	06h48m	+20°54'	176.7°	0.8°	314°
Today	30 Dec 2025	26.8	11.840 AU	12.323 AU	14h57m	+00°03'	58.6°	4.1°	297°

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. (10.6 + 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/2020 X2 (ATLAS) are:

    e (Eccentricity)                : 0.7683810
    q (Perihelion distance)         : 3.8353070
    i (Inclination)                 : 18.18710
    Ω (Longitude of ascending node) : 105.35130
    ω (Argument of perihelion)      : 347.61920
    L (Longitude of perihelion)     : 93.57130
    B (Latitude of perihelion)      : -3.83717
    T (Time of perihelion passage)  : 2459170.79870
    P (Orbital period in years)     : 67.38

    Epoch                           : 2025 Dec 29
    Reference                       : MPEC 2024-A43

    Classification(s):              : Nearly isotropic; Returning (a < 10000 AU); Halley type (P < 200 years)

Ephemerides

Date       Time       RA (2000)    DEC (2000)    delta   radius  elong  phase   PA    magn
2025-12-29 00:00 UT   14 57 12.3   +00 03 19    12.341   11.832   56.9    4.0   298   26.8 
2025-12-30 00:00 UT   14 57 27.6   +00 03 10    12.331   11.837   57.8    4.0   298   26.8 
2025-12-30 21:12 UT   14 57 40.9   +00 03 04    12.323   11.840   58.6    4.1   297   26.8 
2025-12-31 00:00 UT   14 57 42.7   +00 03 04    12.322   11.841   58.7    4.1   297   26.8 
2026-01-01 00:00 UT   14 57 57.5   +00 02 59    12.312   11.845   59.6    4.1   297   26.8 
2026-01-02 00:00 UT   14 58 12.1   +00 02 56    12.302   11.849   60.5    4.1   297   26.8 
2026-01-03 00:00 UT   14 58 26.4   +00 02 56    12.292   11.854   61.4    4.2   296   26.8 
2026-01-04 00:00 UT   14 58 40.5   +00 02 57    12.282   11.858   62.3    4.2   296   26.8 
2026-01-05 00:00 UT   14 58 54.3   +00 03 00    12.272   11.862   63.3    4.2   296   26.8 
2026-01-06 00:00 UT   14 59 07.9   +00 03 06    12.261   11.866   64.2    4.3   295   26.8 
2026-01-07 00:00 UT   14 59 21.3   +00 03 13    12.251   11.870   65.1    4.3   295   26.8 
2026-01-08 00:00 UT   14 59 34.4   +00 03 22    12.240   11.875   66.0    4.3   295   26.8 
2026-01-09 00:00 UT   14 59 47.2   +00 03 33    12.229   11.879   66.9    4.4   294   26.8 

    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.