C/2020 M3 (ATLAS)
ephemeris	date	magn	radius	delta	ra	dec	elong	phase	PA
Perihelion	25 Oct 2020	8.3	1.277 AU	0.413 AU	05h08m	-17°04'	125.1°	39.6°	299°
Nearest approach	14 Nov 2020	8.2	1.311 AU	0.366 AU	05h24m	+05°00'	146.7°	24.5°	296°
Today	16 Nov 2025	33.4	14.339 AU	15.046 AU	13h24m	+12°07'	43.0°	2.7°	315°

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[∆] + 16.5 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 M3 (ATLAS) are:

    e (Eccentricity)                : 0.9532600
    q (Perihelion distance)         : 1.2769290
    i (Inclination)                 : 23.46770
    Ω (Longitude of ascending node) : 71.18860
    ω (Argument of perihelion)      : 328.68280
    L (Longitude of perihelion)     : 42.02293
    B (Latitude of perihelion)      : -11.94609
    T (Time of perihelion passage)  : 2459148.06170
    P (Orbital period in years)     : 142.80

    Epoch                           : 2025 Nov 12
    Reference                       : MPEC 2022-H30

    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
2025-11-15 00:00 UT   13 24 10.1   +12 07 58    15.053   14.332   41.9    2.6   316   33.4 
2025-11-16 00:00 UT   13 24 24.3   +12 07 18    15.048   14.337   42.7    2.7   316   33.4 
2025-11-16 08:00 UT   13 24 29.0   +12 07 05    15.046   14.339   43.0    2.7   315   33.4 
2025-11-17 00:00 UT   13 24 38.4   +12 06 40    15.043   14.342   43.5    2.7   315   33.4 
2025-11-18 00:00 UT   13 24 52.4   +12 06 04    15.037   14.348   44.4    2.8   314   33.4 
2025-11-19 00:00 UT   13 25 06.2   +12 05 30    15.031   14.353   45.2    2.8   314   33.4 
2025-11-20 00:00 UT   13 25 19.9   +12 04 58    15.026   14.358   46.1    2.8   313   33.4 
2025-11-21 00:00 UT   13 25 33.5   +12 04 29    15.019   14.363   46.9    2.9   312   33.4 
2025-11-22 00:00 UT   13 25 46.9   +12 04 01    15.013   14.368   47.8    2.9   312   33.4 
2025-11-23 00:00 UT   13 26 00.2   +12 03 35    15.007   14.374   48.6    3.0   311   33.5 
2025-11-24 00:00 UT   13 26 13.3   +12 03 11    15.000   14.379   49.5    3.0   311   33.5 
2025-11-25 00:00 UT   13 26 26.3   +12 02 49    14.993   14.384   50.4    3.0   310   33.5 
2025-11-26 00:00 UT   13 26 39.1   +12 02 29    14.986   14.389   51.2    3.1   310   33.5 

    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.