C/2021 G2 (ATLAS)
ephemeris	date	magn	radius	delta	ra	dec	elong	phase	PA
Nearest approach	15 Apr 2024	13.5	5.109 AU	4.238 AU	11h55m	-33°41'	147.1°	6.1°	49°
Perihelion	9 Sep 2024	14.0	4.982 AU	5.743 AU	13h07m	-18°50'	37.5°	7.1°	127°
Today	26 Jun 2025	14.0	5.454 AU	4.766 AU	15h05m	-01°54'	128.2°	8.4°	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.)

The orbital elements of C/2021 G2 (ATLAS) are:

            e (Eccentricity)                : 1.0007280
            q (Perihelion distance)         : 4.9822860
            i (Inclination)                 : 48.46690
            Ω (Longitude of ascending node) : 221.09460
            ω (Argument of perihelion)      : 343.26670
            L (Longitude of perihelion)     : 209.82073
            B (Latitude of perihelion)      : -12.44644
            T (Time of perihelion passage)  : 2460562.63670

            Epoch                           : 2025 Jun 24
            Reference                       : MPC184409

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

The light curve chart below shows the estimated development of the comet's magnitude. Blue and black dots are visual and photometric CCD observations respectively from COBS or the MPC. The gray curve is based on the absolute magnitude and slope parameter as calculated from the original MPEC, or the latest values provided by the MPC (5.50 + 5 log[∆] + 10.00 log[r]), whereas the red curve is being recalculated every 6 hours based on the available COBS/MPC observations (currently 3.27 + 5 log[∆] + 10.00 log[r]).

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.
A more printer-friendly version of the same chart can be found further down this page as well.

The following chart shows the current location of the comet in a smaller, upside-down telescopic field of view.

A printable version of the short-term path of the comet in a field of view that is optimized for (~10x50) binoculars and finderscopes.

Ephemerides:

Date       Time       RA (2000)    DEC (2000)    delta   radius  elong  phase   PA    magn
2025-06-26 00:00 UT   15 05 23.8   -01 55 11     4.762    5.453  128.5    8.4   119   14.0 
2025-06-26 07:25 UT   15 05 21.4   -01 54 03     4.766    5.454  128.2    8.4   119   14.0 
2025-06-27 00:00 UT   15 05 16.3   -01 51 33     4.777    5.456  127.6    8.5   118   14.0 
2025-06-28 00:00 UT   15 05 09.4   -01 48 00     4.792    5.459  126.6    8.6   118   14.0 
2025-06-29 00:00 UT   15 05 03.2   -01 44 34     4.807    5.463  125.7    8.7   118   14.1 
2025-06-30 00:00 UT   15 04 57.5   -01 41 13     4.822    5.466  124.7    8.8   117   14.1 
2025-07-01 00:00 UT   15 04 52.5   -01 37 59     4.838    5.469  123.8    8.9   117   14.1 
2025-07-02 00:00 UT   15 04 48.2   -01 34 50     4.854    5.472  122.8    9.0   117   14.1 
2025-07-03 00:00 UT   15 04 44.4   -01 31 47     4.869    5.475  121.9    9.1   116   14.1 
2025-07-04 00:00 UT   15 04 41.3   -01 28 50     4.885    5.478  120.9    9.2   116   14.1 
2025-07-05 00:00 UT   15 04 38.9   -01 25 58     4.902    5.481  120.0    9.2   116   14.1 
2025-07-06 00:00 UT   15 04 37.1   -01 23 12     4.918    5.484  119.1    9.3   115   14.1 

    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.