C/2021 G3 (PANSTARRS)
ephemeris	date	magn	radius	delta	ra	dec	elong	phase	PA
Perihelion	18 Oct 2021	21.4	5.188 AU	5.747 AU	10h36m	+18°52'	51.6°	8.7°	300°
Nearest approach	5 Feb 2022	20.9	5.254 AU	4.368 AU	10h28m	+39°48'	151.3°	5.2°	219°
Today	13 Aug 2026	27.1	12.843 AU	12.530 AU	21h08m	+59°28'	105.8°	4.4°	174°

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. The light curve is based on the absolute magnitude and slope parameter as calculated from an MPEC, or the latest values provided by the minor planet center. (10.5 + 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 G3 (PANSTARRS) are:

    e (Eccentricity)                : 0.9997920
    q (Perihelion distance)         : 5.1878030
    i (Inclination)                 : 102.88070
    Ω (Longitude of ascending node) : 147.31800
    ω (Argument of perihelion)      : 10.65570
    L (Longitude of perihelion)     : 144.91625
    B (Latitude of perihelion)      : 10.38455
    T (Time of perihelion passage)  : 2459505.62030

    Epoch                           : 2026 Jul 19
    Reference                       : MPC194174

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

Ephemerides

Date       Time       RA (2000)    DEC (2000)    delta   radius  elong  phase   PA    magn
2026-08-12 00:00 UT   21 09 01.5   +59 32 07    12.529   12.833  105.3    4.4   176   27.1 
2026-08-13 00:00 UT   21 08 28.7   +59 30 07    12.530   12.839  105.5    4.4   175   27.1 
2026-08-13 20:29 UT   21 08 00.7   +59 28 20    12.530   12.843  105.8    4.4   174   27.1 
2026-08-14 00:00 UT   21 07 56.0   +59 28 02    12.530   12.844  105.8    4.4   174   27.1 
2026-08-15 00:00 UT   21 07 23.4   +59 25 51    12.531   12.849  106.1    4.3   173   27.1 
2026-08-16 00:00 UT   21 06 50.9   +59 23 36    12.532   12.854  106.4    4.3   171   27.1 
2026-08-17 00:00 UT   21 06 18.7   +59 21 15    12.533   12.860  106.6    4.3   170   27.1 
2026-08-18 00:00 UT   21 05 46.6   +59 18 50    12.534   12.865  106.9    4.3   169   27.1 
2026-08-19 00:00 UT   21 05 14.7   +59 16 19    12.535   12.870  107.2    4.3   168   27.1 
2026-08-20 00:00 UT   21 04 43.0   +59 13 44    12.536   12.875  107.4    4.3   167   27.1 
2026-08-21 00:00 UT   21 04 11.6   +59 11 04    12.537   12.881  107.6    4.3   166   27.1 
2026-08-22 00:00 UT   21 03 40.4   +59 08 19    12.539   12.886  107.9    4.3   165   27.1 
2026-08-23 00:00 UT   21 03 09.4   +59 05 29    12.540   12.891  108.1    4.3   164   27.1 

    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.