C/2020 K6 (Rankin)
ephemeris	date	magn	radius	delta	ra	dec	elong	phase	PA
Nearest approach	1 Jul 2021	19.2	5.889 AU	5.099 AU	18h37m	+19°23'	137.5°	6.7°	178°
Perihelion	14 Sep 2021	19.5	5.865 AU	5.730 AU	17h45m	+20°34'	92.8°	9.9°	95°
Today	12 Dec 2025	23.9	11.704 AU	11.237 AU	10h27m	+61°02'	116.1°	4.3°	271°

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. (8.0 + 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/2020 K6 (Rankin) are:

    e (Eccentricity)                : 1.0016060
    q (Perihelion distance)         : 5.8652660
    i (Inclination)                 : 103.62730
    Ω (Longitude of ascending node) : 291.60310
    ω (Argument of perihelion)      : 44.25610
    L (Longitude of perihelion)     : 278.67399
    B (Latitude of perihelion)      : 42.70478
    T (Time of perihelion passage)  : 2459471.77590

    Epoch                           : 2025 Dec 11
    Reference                       : MPEC 2023-N01

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

Ephemerides

Date       Time       RA (2000)    DEC (2000)    delta   radius  elong  phase   PA    magn
2025-12-11 00:00 UT   10 28 08.0   +60 57 16    11.243   11.696  115.2    4.4   272   23.9 
2025-12-12 00:00 UT   10 27 46.4   +61 00 44    11.239   11.701  115.8    4.3   271   23.9 
2025-12-12 10:58 UT   10 27 36.2   +61 02 19    11.237   11.704  116.1    4.3   271   23.9 
2025-12-13 00:00 UT   10 27 23.9   +61 04 12    11.234   11.706  116.4    4.3   270   23.9 
2025-12-14 00:00 UT   10 27 00.7   +61 07 40    11.230   11.711  117.1    4.3   269   23.9 
2025-12-15 00:00 UT   10 26 36.7   +61 11 08    11.226   11.716  117.7    4.3   268   23.9 
2025-12-16 00:00 UT   10 26 11.8   +61 14 36    11.222   11.721  118.3    4.2   267   23.9 
2025-12-17 00:00 UT   10 25 46.2   +61 18 04    11.218   11.726  118.9    4.2   266   23.9 
2025-12-18 00:00 UT   10 25 19.8   +61 21 31    11.214   11.731  119.6    4.2   265   23.9 
2025-12-19 00:00 UT   10 24 52.6   +61 24 57    11.211   11.736  120.2    4.2   264   23.9 
2025-12-20 00:00 UT   10 24 24.6   +61 28 23    11.208   11.741  120.7    4.1   263   23.9 
2025-12-21 00:00 UT   10 23 55.8   +61 31 48    11.204   11.746  121.3    4.1   262   23.9 
2025-12-22 00:00 UT   10 23 26.2   +61 35 11    11.202   11.751  121.9    4.1   260   23.9 

    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.