C/2018 K1 (Weiland)
ephemeris	date	magn	radius	delta	ra	dec	elong	phase	PA
Perihelion	8 Apr 2018	18.4	1.880 AU	2.218 AU	21h43m	-21°41'	57.5°	26.7°	246°
Nearest approach	9 Jun 2018	17.0	2.025 AU	1.017 AU	17h51m	-25°09'	170.0°	5.0°	281°
Today	13 Mar 2025	32.4	17.274 AU	16.418 AU	10h13m	+27°28'	148.5°	1.7°	138°

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.)

The orbital elements of C/2018 K1 (Weiland) are:

            e (Eccentricity)                : 0.9378170
            q (Perihelion distance)         : 1.8796280
            i (Inclination)                 : 164.18610
            Ω (Longitude of ascending node) : 260.20330
            ω (Argument of perihelion)      : 325.25290
            L (Longitude of perihelion)     : 293.92230
            B (Latitude of perihelion)      : -8.93539
            T (Time of perihelion passage)  : 2458216.66380
            P (Orbital period in years)     : 166.19

            Epoch                           : 2023 Apr 14
            Reference                       : MPC114602

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

The light curve chart below shows the estimated development of the comet's magnitude. Blue and black dots are visual and photometric CCD observations respectively from COBS or the MPC. The gray curve is based on the absolute magnitude and slope parameter as calculated from the original MPEC, or the latest values provided by the MPC (14.90 + 5 log[∆] + 10.00 log[r]), whereas the red curve is being recalculated every 6 hours based on the available COBS/MPC observations (currently 13.92 + 5 log[∆] + 10.00 log[r]).

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.
A more printer-friendly version of the same chart can be found further down this page as well.

The following chart shows the current location of the comet in a smaller, upside-down telescopic field of view.

A printable version of the short-term path of the comet in a field of view that is optimized for (~10x50) binoculars and finderscopes.

Ephemerides:

Date       Time       RA (2000)    DEC (2000)    delta   radius  elong  phase   PA    magn
2025-03-13 00:00 UT   10 13 23.5   +27 28 13    16.408   17.270  149.2    1.7   139   32.4 
2025-03-13 20:20 UT   10 13 10.0   +27 28 57    16.418   17.274  148.5    1.7   138   32.4 
2025-03-14 00:00 UT   10 13 07.5   +27 29 05    16.420   17.275  148.3    1.7   138   32.4 
2025-03-15 00:00 UT   10 12 51.7   +27 29 56    16.433   17.279  147.4    1.8   137   32.4 
2025-03-16 00:00 UT   10 12 36.0   +27 30 45    16.445   17.284  146.5    1.8   136   32.4 
2025-03-17 00:00 UT   10 12 20.5   +27 31 33    16.458   17.288  145.6    1.9   135   32.4 
2025-03-18 00:00 UT   10 12 05.0   +27 32 18    16.471   17.293  144.6    1.9   134   32.4 
2025-03-19 00:00 UT   10 11 49.7   +27 33 03    16.485   17.297  143.7    2.0   133   32.4 
2025-03-20 00:00 UT   10 11 34.6   +27 33 45    16.498   17.302  142.8    2.0   133   32.4 
2025-03-21 00:00 UT   10 11 19.5   +27 34 26    16.512   17.307  141.8    2.0   132   32.4 
2025-03-22 00:00 UT   10 11 04.7   +27 35 05    16.526   17.311  140.9    2.1   131   32.4 
2025-03-23 00:00 UT   10 10 50.0   +27 35 42    16.541   17.316  139.9    2.1   130   32.4 

    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.