C/2018 K1 (Weiland)
ephemeris	date	magn	radius	delta	ra	dec	elong	phase	PA
Perihelion	9 Apr 2018	18.3	1.860 AU	2.187 AU	21h46m	-21°31'	57.9°	27.1°	246°
Nearest approach	9 Jun 2018	16.9	2.004 AU	0.996 AU	17h52m	-25°15'	170.0°	5.0°	281°
Today	15 Nov 2026	33.4	19.931 AU	19.972 AU	10h15m	+25°58'	86.2°	2.8°	293°

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 13.9 + 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/2018 K1 (Weiland) are:

    e (Eccentricity)                : 0.9380720
    q (Perihelion distance)         : 1.8597350
    i (Inclination)                 : 164.18280
    Ω (Longitude of ascending node) : 260.24880
    ω (Argument of perihelion)      : 325.06250
    L (Longitude of perihelion)     : 294.15512
    B (Latitude of perihelion)      : -8.98034
    T (Time of perihelion passage)  : 2458217.80370
    P (Orbital period in years)     : 164.57

    Epoch                           : 2026 May 29
    Reference                       : MPC194156

    Classification(s):              : Nearly isotropic; Returning (a < 10000 AU); Halley type (P < 200 years)

Ephemerides

Date       Time       RA (2000)    DEC (2000)    delta   radius  elong  phase   PA    magn
2026-11-14 00:00 UT   10 15 44.0   +25 57 32    19.988   19.926   85.0    2.8   293   33.4 
2026-11-15 00:00 UT   10 15 44.6   +25 58 13    19.975   19.931   86.0    2.8   293   33.4 
2026-11-15 04:36 UT   10 15 44.7   +25 58 22    19.972   19.931   86.2    2.8   293   33.4 
2026-11-16 00:00 UT   10 15 45.1   +25 58 56    19.962   19.935   87.0    2.8   292   33.4 
2026-11-17 00:00 UT   10 15 45.4   +25 59 40    19.949   19.939   87.9    2.8   292   33.4 
2026-11-18 00:00 UT   10 15 45.4   +26 00 25    19.936   19.943   88.9    2.8   292   33.4 
2026-11-19 00:00 UT   10 15 45.2   +26 01 12    19.924   19.947   89.9    2.8   292   33.4 
2026-11-20 00:00 UT   10 15 44.8   +26 01 60    19.911   19.951   90.9    2.8   291   33.4 
2026-11-21 00:00 UT   10 15 44.2   +26 02 48    19.898   19.955   91.9    2.8   291   33.4 
2026-11-22 00:00 UT   10 15 43.4   +26 03 39    19.885   19.960   92.9    2.8   291   33.4 
2026-11-23 00:00 UT   10 15 42.4   +26 04 30    19.872   19.964   93.9    2.8   291   33.4 
2026-11-24 00:00 UT   10 15 41.1   +26 05 22    19.860   19.968   94.8    2.8   290   33.4 
2026-11-25 00:00 UT   10 15 39.6   +26 06 16    19.847   19.972   95.8    2.8   290   33.4 

    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.