C/2021 G2 (ATLAS)
ephemeris	date	magn	radius	delta	ra	dec	elong	phase	PA
Nearest approach	15 Apr 2024	13.7	5.109 AU	4.238 AU	11h55m	-33°40'	147.1°	6.1°	49°
Perihelion	9 Sep 2024	14.2	4.982 AU	5.743 AU	13h07m	-18°50'	37.5°	7.1°	127°
Today	22 Mar 2026	15.6	6.519 AU	6.287 AU	17h29m	+07°38'	99.1°	8.7°	268°

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 3.5 + 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/2021 G2 (ATLAS) are:

    e (Eccentricity)                : 1.0010760
    q (Perihelion distance)         : 4.9820250
    i (Inclination)                 : 48.45870
    Ω (Longitude of ascending node) : 221.08800
    ω (Argument of perihelion)      : 343.26760
    L (Longitude of perihelion)     : 209.81298
    B (Latitude of perihelion)      : -12.44418
    T (Time of perihelion passage)  : 2460562.66000

    Epoch                           : 2026 Mar 22
    Reference                       : MPEC 2026-FC3

    Classification(s):              : Nearly isotropic; New (a > 10000 AU)

Ephemerides

Date       Time       RA (2000)    DEC (2000)    delta   radius  elong  phase   PA    magn
2026-03-21 00:00 UT   17 29 38.1   +07 24 17     6.304    6.511   97.5    8.7   269   15.6 
2026-03-22 00:00 UT   17 29 47.7   +07 31 31     6.295    6.515   98.4    8.7   268   15.6 
2026-03-22 21:45 UT   17 29 55.8   +07 38 04     6.287    6.519   99.1    8.7   268   15.6 
2026-03-23 00:00 UT   17 29 56.6   +07 38 45     6.286    6.520   99.2    8.7   268   15.6 
2026-03-24 00:00 UT   17 30 04.9   +07 46 00     6.277    6.524  100.0    8.7   267   15.6 
2026-03-25 00:00 UT   17 30 12.6   +07 53 16     6.269    6.529  100.8    8.6   267   15.6 
2026-03-26 00:00 UT   17 30 19.7   +08 00 32     6.260    6.534  101.6    8.6   266   15.6 
2026-03-27 00:00 UT   17 30 26.1   +08 07 49     6.251    6.538  102.4    8.6   266   15.6 
2026-03-28 00:00 UT   17 30 31.9   +08 15 07     6.243    6.543  103.2    8.5   265   15.6 
2026-03-29 00:00 UT   17 30 37.2   +08 22 25     6.234    6.548  104.0    8.5   265   15.6 
2026-03-30 00:00 UT   17 30 41.8   +08 29 43     6.226    6.552  104.8    8.5   264   15.6 
2026-03-31 00:00 UT   17 30 45.7   +08 37 01     6.217    6.557  105.6    8.4   263   15.6 
2026-04-01 00:00 UT   17 30 49.1   +08 44 20     6.209    6.562  106.4    8.4   263   15.6 

    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.