C/2020 H6 (ATLAS)
ephemeris	date	magn	radius	delta	ra	dec	elong	phase	PA
Nearest approach	30 Apr 2021	15.6	4.847 AU	3.847 AU	13h59m	-12°27'	172.3°	1.6°	108°
Perihelion	29 Sep 2021	16.2	4.695 AU	5.533 AU	14h21m	+03°40'	30.3°	6.2°	79°
Today	13 Mar 2026	22.6	12.212 AU	12.749 AU	23h00m	+51°58'	55.4°	3.8°	350°

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)                : 0.9973510
    q (Perihelion distance)         : 4.6954290
    i (Inclination)                 : 80.00300
    Ω (Longitude of ascending node) : 213.66800
    ω (Argument of perihelion)      : 20.17260
    L (Longitude of perihelion)     : 217.31720
    B (Latitude of perihelion)      : 19.85333
    T (Time of perihelion passage)  : 2459486.84710
    P (Orbital period in years)     : 74625.97

    Epoch                           : 2026 Mar 12
    Reference                       : MPEC 2026-E44

    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
2026-03-12 00:00 UT   22 59 51.1   +51 57 02    12.735   12.205   55.8    3.9   352   22.6 
2026-03-13 00:00 UT   23 00 25.2   +51 57 57    12.745   12.210   55.5    3.8   351   22.6 
2026-03-13 09:00 UT   23 00 38.0   +51 58 18    12.749   12.212   55.4    3.8   350   22.6 
2026-03-14 00:00 UT   23 00 59.3   +51 58 55    12.755   12.216   55.2    3.8   350   22.6 
2026-03-15 00:00 UT   23 01 33.2   +51 59 56    12.765   12.221   54.9    3.8   349   22.6 
2026-03-16 00:00 UT   23 02 07.1   +52 00 60    12.775   12.227   54.6    3.8   348   22.6 
2026-03-17 00:00 UT   23 02 40.8   +52 02 07    12.785   12.232   54.4    3.8   347   22.6 
2026-03-18 00:00 UT   23 03 14.4   +52 03 17    12.794   12.238   54.1    3.8   346   22.6 
2026-03-19 00:00 UT   23 03 47.9   +52 04 31    12.803   12.243   53.9    3.8   345   22.6 
2026-03-20 00:00 UT   23 04 21.3   +52 05 48    12.813   12.249   53.6    3.8   344   22.6 
2026-03-21 00:00 UT   23 04 54.5   +52 07 07    12.822   12.254   53.4    3.7   343   22.6 
2026-03-22 00:00 UT   23 05 27.6   +52 08 30    12.830   12.259   53.2    3.7   342   22.6 
2026-03-23 00:00 UT   23 06 00.6   +52 09 56    12.839   12.265   53.0    3.7   341   22.6 

    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.