C/2017 K2 (PANSTARRS)
ephemeris	date	magn	radius	delta	ra	dec	elong	phase	PA
Nearest approach	13 Jul 2022	8.9	2.641 AU	1.788 AU	16h59m	-03°50'	139.1°	14.6°	119°
Perihelion	17 Dec 2022	8.4	1.801 AU	2.485 AU	17h51m	-60°22'	37.1°	19.2°	176°
Today	5 Aug 2026	17.6	11.732 AU	12.469 AU	06h09m	+32°56'	41.7°	3.3°	282°

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 4.7 + 5 log[∆] + 7.0 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/2017 K2 (PANSTARRS) are:

    e (Eccentricity)                : 0.9983370
    q (Perihelion distance)         : 1.8005470
    i (Inclination)                 : 87.65000
    Ω (Longitude of ascending node) : 88.22340
    ω (Argument of perihelion)      : 236.14340
    L (Longitude of perihelion)     : 91.72096
    B (Latitude of perihelion)      : -56.07164
    T (Time of perihelion passage)  : 2459931.24490
    P (Orbital period in years)     : 35626.10

    Epoch                           : 2026 Aug 04
    Reference                       : MPEC 2026-O98

    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
2026-08-04 00:00 UT   06 08 40.1   +32 54 21    12.476   11.722   40.4    3.2   282   17.6 
2026-08-05 00:00 UT   06 08 56.8   +32 55 35    12.471   11.728   41.3    3.3   282   17.6 
2026-08-05 12:02 UT   06 09 05.2   +32 56 12    12.469   11.732   41.7    3.3   282   17.6 
2026-08-06 00:00 UT   06 09 13.4   +32 56 49    12.467   11.735   42.1    3.3   282   17.6 
2026-08-07 00:00 UT   06 09 29.7   +32 58 04    12.462   11.741   43.0    3.4   281   17.6 
2026-08-08 00:00 UT   06 09 45.8   +32 59 20    12.457   11.748   43.9    3.4   281   17.6 
2026-08-09 00:00 UT   06 10 01.7   +33 00 36    12.452   11.754   44.8    3.5   281   17.6 
2026-08-10 00:00 UT   06 10 17.3   +33 01 52    12.447   11.761   45.7    3.5   281   17.6 
2026-08-11 00:00 UT   06 10 32.7   +33 03 10    12.441   11.767   46.5    3.6   280   17.6 
2026-08-12 00:00 UT   06 10 47.8   +33 04 27    12.435   11.774   47.4    3.6   280   17.6 
2026-08-13 00:00 UT   06 11 02.6   +33 05 46    12.429   11.780   48.3    3.7   280   17.6 
2026-08-14 00:00 UT   06 11 17.3   +33 07 05    12.423   11.787   49.2    3.7   280   17.6 
2026-08-15 00:00 UT   06 11 31.6   +33 08 24    12.417   11.793   50.1    3.8   279   17.6 

    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.