C/2017 K1 (PANSTARRS)
ephemeris	date	magn	radius	delta	ra	dec	elong	phase	PA
Perihelion	17 Mar 2018	19.7	7.280 AU	6.616 AU	15h04m	-15°08'	128.7°	6.1°	284°
Nearest approach	29 Apr 2018	19.6	7.285 AU	6.280 AU	14h31m	-10°55'	176.2°	0.5°	199°
Today	23 Oct 2025	25.6	17.382 AU	17.429 AU	08h58m	+43°24'	85.7°	3.3°	290°

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. (7.0 + 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/2017 K1 (PANSTARRS) are:

    e (Eccentricity)                : 1.0032030
    q (Perihelion distance)         : 7.2795730
    i (Inclination)                 : 154.02210
    Ω (Longitude of ascending node) : 225.74120
    ω (Argument of perihelion)      : 4.38870
    L (Longitude of perihelion)     : 221.79444
    B (Latitude of perihelion)      : 1.92084
    T (Time of perihelion passage)  : 2458195.01890

    Epoch                           : 2023 Apr 14
    Reference                       : MPC115882

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

Ephemerides

Date       Time       RA (2000)    DEC (2000)    delta   radius  elong  phase   PA    magn
2025-10-22 00:00 UT   08 58 14.6   +43 22 54    17.440   17.378   84.8    3.3   290   25.6 
2025-10-23 00:00 UT   08 58 14.2   +43 24 23    17.429   17.382   85.7    3.3   290   25.6 
2025-10-23 00:12 UT   08 58 14.2   +43 24 23    17.429   17.382   85.7    3.3   290   25.6 
2025-10-24 00:00 UT   08 58 13.4   +43 25 53    17.417   17.387   86.6    3.3   290   25.6 
2025-10-25 00:00 UT   08 58 12.4   +43 27 24    17.406   17.391   87.5    3.3   289   25.6 
2025-10-26 00:00 UT   08 58 11.0   +43 28 56    17.394   17.396   88.4    3.3   289   25.6 
2025-10-27 00:00 UT   08 58 09.3   +43 30 30    17.383   17.400   89.3    3.3   288   25.6 
2025-10-28 00:00 UT   08 58 07.3   +43 32 05    17.372   17.405   90.2    3.3   288   25.6 
2025-10-29 00:00 UT   08 58 05.0   +43 33 41    17.360   17.409   91.2    3.3   287   25.6 
2025-10-30 00:00 UT   08 58 02.4   +43 35 19    17.349   17.414   92.1    3.3   287   25.6 
2025-10-31 00:00 UT   08 57 59.4   +43 36 57    17.337   17.418   93.0    3.3   287   25.6 
2025-11-01 00:00 UT   08 57 56.1   +43 38 37    17.326   17.423   93.9    3.3   286   25.6 
2025-11-02 00:00 UT   08 57 52.5   +43 40 18    17.315   17.427   94.8    3.3   286   25.6 

    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.