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°41'	30.3°	6.2°	79°
Today	1 May 2026	22.7	12.477 AU	13.055 AU	23h24m	+53°37'	53.1°	3.7°	298°

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)                : 0.9973220
    q (Perihelion distance)         : 4.6952490
    i (Inclination)                 : 80.00680
    Ω (Longitude of ascending node) : 213.66240
    ω (Argument of perihelion)      : 20.17080
    L (Longitude of perihelion)     : 217.30988
    B (Latitude of perihelion)      : 19.85180
    T (Time of perihelion passage)  : 2459486.82270
    P (Orbital period in years)     : 73412.85

    Epoch                           : 2026 Apr 30
    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
2026-04-30 00:00 UT   23 24 23.2   +53 34 32    13.053   12.471   52.9    3.7   300   22.7 
2026-05-01 00:00 UT   23 24 47.1   +53 37 24    13.055   12.477   53.1    3.7   298   22.7 
2026-05-01 01:00 UT   23 24 48.1   +53 37 31    13.055   12.477   53.1    3.7   298   22.7 
2026-05-02 00:00 UT   23 25 10.7   +53 40 16    13.058   12.482   53.3    3.7   297   22.7 
2026-05-03 00:00 UT   23 25 34.0   +53 43 11    13.060   12.488   53.5    3.7   296   22.7 
2026-05-04 00:00 UT   23 25 57.0   +53 46 06    13.062   12.493   53.8    3.7   295   22.8 
2026-05-05 00:00 UT   23 26 19.6   +53 49 03    13.064   12.499   54.0    3.7   294   22.8 
2026-05-06 00:00 UT   23 26 41.9   +53 52 01    13.065   12.504   54.3    3.8   293   22.8 
2026-05-07 00:00 UT   23 27 03.9   +53 55 00    13.067   12.509   54.5    3.8   292   22.8 
2026-05-08 00:00 UT   23 27 25.5   +53 58 01    13.069   12.515   54.8    3.8   291   22.8 
2026-05-09 00:00 UT   23 27 46.8   +54 01 02    13.070   12.520   55.1    3.8   290   22.8 
2026-05-10 00:00 UT   23 28 07.7   +54 04 05    13.071   12.526   55.4    3.8   289   22.8 
2026-05-11 00:00 UT   23 28 28.3   +54 07 08    13.072   12.531   55.7    3.8   288   22.8 

    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.