C/2021 C5 (PANSTARRS)
ephemeris	date	magn	radius	delta	ra	dec	elong	phase	PA
Perihelion	11 Feb 2023	16.8	3.237 AU	3.417 AU	16h40m	-69°59'	71.2°	16.8°	260°
Nearest approach	20 Jun 2023	16.6	3.463 AU	2.800 AU	20h10m	-77°51'	123.3°	14.2°	322°
Today	28 Aug 2026	24.3	10.744 AU	9.795 AU	22h15m	+11°14'	158.9°	1.9°	172°

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. (9.0 + 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 C5 (PANSTARRS) are:

    e (Eccentricity)                : 0.9981130
    q (Perihelion distance)         : 3.2372550
    i (Inclination)                 : 50.80910
    Ω (Longitude of ascending node) : 323.67600
    ω (Argument of perihelion)      : 270.84860
    L (Longitude of perihelion)     : 235.01877
    B (Latitude of perihelion)      : -50.80139
    T (Time of perihelion passage)  : 2459986.64790
    P (Orbital period in years)     : 71057.11

    Epoch                           : 2026 Aug 27
    Reference                       : MPC194173

    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
2026-08-27 00:00 UT   22 16 13.3   +11 15 40     9.786   10.733  158.4    2.0   177   24.3 
2026-08-28 00:00 UT   22 15 52.6   +11 14 52     9.791   10.739  158.7    2.0   174   24.3 
2026-08-28 18:55 UT   22 15 36.2   +11 14 12     9.795   10.744  158.9    1.9   172   24.3 
2026-08-29 00:00 UT   22 15 31.8   +11 14 01     9.796   10.745  159.0    1.9   171   24.3 
2026-08-30 00:00 UT   22 15 11.2   +11 13 08     9.801   10.751  159.1    1.9   168   24.3 
2026-08-31 00:00 UT   22 14 50.6   +11 12 13     9.807   10.758  159.3    1.9   165   24.3 
2026-09-01 00:00 UT   22 14 30.0   +11 11 16     9.813   10.764  159.4    1.9   162   24.3 
2026-09-02 00:00 UT   22 14 09.5   +11 10 17     9.819   10.770  159.4    1.9   159   24.3 
2026-09-03 00:00 UT   22 13 49.1   +11 09 16     9.826   10.776  159.4    1.9   156   24.3 
2026-09-04 00:00 UT   22 13 28.8   +11 08 13     9.832   10.782  159.3    1.9   153   24.3 
2026-09-05 00:00 UT   22 13 08.6   +11 07 08     9.839   10.788  159.2    1.9   150   24.3 
2026-09-06 00:00 UT   22 12 48.4   +11 06 01     9.847   10.795  159.0    1.9   147   24.3 
2026-09-07 00:00 UT   22 12 28.4   +11 04 52     9.854   10.801  158.8    1.9   145   24.3 

    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.