C/2017 K2 (PANSTARRS)
ephemeris	date	magn	radius	delta	ra	dec	elong	phase	PA
Nearest approach	13 Jul 2022	8.9	2.644 AU	1.792 AU	16h59m	-03°43'	139.0°	14.6°	119°
Perihelion	18 Dec 2022	8.5	1.800 AU	2.485 AU	17h52m	-60°22'	37.1°	19.2°	176°
Today	8 Jan 2026	16.6	10.338 AU	9.425 AU	05h43m	+30°58'	157.0°	2.1°	107°

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 4.8 + 5 log[∆] + 6.9 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)                : 0.9985790
    q (Perihelion distance)         : 1.8001830
    i (Inclination)                 : 87.63890
    Ω (Longitude of ascending node) : 88.22160
    ω (Argument of perihelion)      : 236.15400
    L (Longitude of perihelion)     : 91.73704
    B (Latitude of perihelion)      : -56.08153
    T (Time of perihelion passage)  : 2459931.61630
    P (Orbital period in years)     : 45090.38

    Epoch                           : 2026 Jan 08
    Reference                       : MPEC 2026-A24

    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
2026-01-07 00:00 UT   05 44 32.3   +30 56 56     9.400   10.325  159.0    2.0   109   16.6 
2026-01-08 00:00 UT   05 44 04.8   +30 57 36     9.413   10.332  157.9    2.0   108   16.6 
2026-01-08 21:51 UT   05 43 40.0   +30 58 12     9.425   10.338  157.0    2.1   107   16.6 
2026-01-09 00:00 UT   05 43 37.5   +30 58 16     9.426   10.338  156.9    2.1   107   16.6 
2026-01-10 00:00 UT   05 43 10.6   +30 58 54     9.440   10.345  155.8    2.2   106   16.6 
2026-01-11 00:00 UT   05 42 43.9   +30 59 30     9.454   10.352  154.8    2.3   105   16.6 
2026-01-12 00:00 UT   05 42 17.4   +31 00 06     9.468   10.359  153.7    2.4   104   16.6 
2026-01-13 00:00 UT   05 41 51.3   +31 00 40     9.482   10.366  152.6    2.5   103   16.7 
2026-01-14 00:00 UT   05 41 25.5   +31 01 13     9.497   10.373  151.6    2.6   103   16.7 
2026-01-15 00:00 UT   05 40 60.0   +31 01 46     9.512   10.380  150.5    2.7   102   16.7 
2026-01-16 00:00 UT   05 40 34.8   +31 02 17     9.527   10.386  149.4    2.8   101   16.7 
2026-01-17 00:00 UT   05 40 10.0   +31 02 47     9.543   10.393  148.4    2.8   101   16.7 
2026-01-18 00:00 UT   05 39 45.5   +31 03 16     9.558   10.400  147.3    2.9   100   16.7 

    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.