C/2020 H6 (ATLAS)
ephemeris	date	magn	radius	delta	ra	dec	elong	phase	PA
Nearest approach	30 Apr 2021	15.6	4.853 AU	3.853 AU	13h59m	-12°27'	172.3°	1.6°	108°
Perihelion	30 Sep 2021	16.2	4.700 AU	5.542 AU	14h21m	+03°39'	29.8°	6.1°	78°
Today	19 Oct 2025	21.9	11.418 AU	10.930 AU	22h07m	+59°37'	117.1°	4.5°	119°

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 5.1 + 5 log[∆] + 11.0 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 H6 (ATLAS) are:

    e (Eccentricity)                : 0.9984330
    q (Perihelion distance)         : 4.6996370
    i (Inclination)                 : 79.97870
    Ω (Longitude of ascending node) : 213.71630
    ω (Argument of perihelion)      : 20.24510
    L (Longitude of perihelion)     : 217.38853
    B (Latitude of perihelion)      : 19.92302
    T (Time of perihelion passage)  : 2459487.62440
    P (Orbital period in years)     : 164245.31

    Epoch                           : 2024 Jun 06
    Reference                       : MPEC 2024-KD0

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

Ephemerides

Date       Time       RA (2000)    DEC (2000)    delta   radius  elong  phase   PA    magn
2025-10-18 00:00 UT   22 07 31.6   +59 44 30    10.921   11.411  117.2    4.5   121   21.9 
2025-10-19 00:00 UT   22 07 20.9   +59 39 19    10.928   11.416  117.1    4.5   120   21.9 
2025-10-19 06:28 UT   22 07 18.1   +59 37 55    10.930   11.418  117.1    4.5   119   21.9 
2025-10-20 00:00 UT   22 07 10.8   +59 34 06    10.934   11.422  117.0    4.5   118   21.9 
2025-10-21 00:00 UT   22 07 01.3   +59 28 51    10.941   11.427  117.0    4.5   117   21.9 
2025-10-22 00:00 UT   22 06 52.5   +59 23 34    10.948   11.433  116.9    4.5   116   21.9 
2025-10-23 00:00 UT   22 06 44.3   +59 18 15    10.956   11.438  116.8    4.5   115   21.9 
2025-10-24 00:00 UT   22 06 36.8   +59 12 54    10.963   11.444  116.6    4.5   114   22.0 
2025-10-25 00:00 UT   22 06 29.9   +59 07 32    10.970   11.449  116.5    4.5   112   22.0 
2025-10-26 00:00 UT   22 06 23.7   +59 02 09    10.978   11.455  116.4    4.5   111   22.0 
2025-10-27 00:00 UT   22 06 18.2   +58 56 44    10.986   11.461  116.2    4.5   110   22.0 
2025-10-28 00:00 UT   22 06 13.2   +58 51 17    10.994   11.466  116.1    4.5   109   22.0 
2025-10-29 00:00 UT   22 06 09.0   +58 45 50    11.002   11.472  115.9    4.5   108   22.0 

    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.