C/2017 K2 (PANSTARRS)
ephemeris	date	magn	radius	delta	ra	dec	elong	phase	PA
Nearest approach	13 Jul 2022	8.9	2.645 AU	1.793 AU	16h59m	-03°41'	138.9°	14.6°	119°
Perihelion	18 Dec 2022	8.5	1.800 AU	2.485 AU	17h52m	-60°22'	37.0°	19.2°	176°
Today	16 Nov 2025	16.5	9.970 AU	9.174 AU	06h09m	+29°53'	141.8°	3.5°	263°

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)                : 0.9986630
    q (Perihelion distance)         : 1.8001000
    i (Inclination)                 : 87.63840
    Ω (Longitude of ascending node) : 88.22160
    ω (Argument of perihelion)      : 236.15810
    L (Longitude of perihelion)     : 91.73832
    B (Latitude of perihelion)      : -56.08559
    T (Time of perihelion passage)  : 2459931.72360
    P (Orbital period in years)     : 49402.38

    Epoch                           : 2025 Nov 15
    Reference                       : MPEC 2025-VD2

    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
2025-11-15 00:00 UT   06 09 42.0   +29 50 12     9.180    9.958  140.0    3.7   263   16.5 
2025-11-16 00:00 UT   06 09 18.1   +29 51 56     9.176    9.965  141.0    3.6   263   16.5 
2025-11-16 17:27 UT   06 09 00.5   +29 53 12     9.174    9.970  141.8    3.5   263   16.5 
2025-11-17 00:00 UT   06 08 53.8   +29 53 40     9.173    9.972  142.1    3.5   263   16.5 
2025-11-18 00:00 UT   06 08 29.2   +29 55 23     9.170    9.979  143.2    3.4   262   16.5 
2025-11-19 00:00 UT   06 08 04.2   +29 57 06     9.167    9.986  144.3    3.3   262   16.5 
2025-11-20 00:00 UT   06 07 38.9   +29 58 47     9.164    9.993  145.3    3.2   261   16.5 
2025-11-21 00:00 UT   06 07 13.2   +30 00 28     9.162   10.000  146.4    3.1   261   16.5 
2025-11-22 00:00 UT   06 06 47.3   +30 02 07     9.160   10.007  147.5    3.0   260   16.5 
2025-11-23 00:00 UT   06 06 21.1   +30 03 46     9.158   10.014  148.6    2.9   260   16.5 
2025-11-24 00:00 UT   06 05 54.5   +30 05 24     9.156   10.021  149.6    2.9   259   16.5 
2025-11-25 00:00 UT   06 05 27.7   +30 07 01     9.155   10.028  150.7    2.8   258   16.5 
2025-11-26 00:00 UT   06 05 00.6   +30 08 37     9.154   10.035  151.8    2.7   258   16.5 

    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.