C/2018 KJ3 (Lemmon)
ephemeris	date	magn	radius	delta	ra	dec	elong	phase	PA
Nearest approach	11 Jun 2019	17.0	3.711 AU	2.735 AU	16h48m	-40°51'	161.3°	5.0°	20°
Perihelion	9 Sep 2019	17.7	3.621 AU	3.966 AU	14h26m	-38°17'	63.0°	14.3°	122°
Today	24 Apr 2024	25.9	12.911 AU	13.172 AU	07h04m	+05°14'	72.8°	4.3°	102°

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 KJ3 (Lemmon) are:

            e (Eccentricity)                : 0.9955810
            q (Perihelion distance)         : 3.6212210
            i (Inclination)                 : 136.63690
            Ω (Longitude of ascending node) : 91.68460
            ω (Argument of perihelion)      : 217.60070
            L (Longitude of perihelion)     : 62.44046
            B (Latitude of perihelion)      : -24.76795
            T (Time of perihelion passage)  : 2458736.17330
            P (Orbital period in years)     : 23458.30

            Epoch                           : 2024 Apr 24
            Reference                       : MPEC 2021-R75

            Classification(s):              : Nearly isotropic; Returning (a < 10000 AU); External (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 (12.20 + 5 log[∆] + 5.00 log[r]), whereas the red curve is being recalculated every 6 hours based on the available COBS/MPC observations (currently 9.16 + 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
2024-04-24 00:00 UT   07 04 35.3   +05 12 50    13.152   12.906   73.7    4.3   102   25.9 
2024-04-24 22:17 UT   07 04 38.6   +05 14 29    13.172   12.911   72.8    4.3   102   25.9 
2024-04-25 00:00 UT   07 04 38.9   +05 14 37    13.173   12.911   72.8    4.3   102   25.9 
2024-04-26 00:00 UT   07 04 42.8   +05 16 23    13.195   12.917   71.8    4.2   102   25.9 
2024-04-27 00:00 UT   07 04 47.0   +05 18 07    13.216   12.923   70.9    4.2   103   25.9 
2024-04-28 00:00 UT   07 04 51.5   +05 19 51    13.237   12.929   70.0    4.2   103   25.9 
2024-04-29 00:00 UT   07 04 56.2   +05 21 33    13.259   12.934   69.1    4.2   103   25.9 
2024-04-30 00:00 UT   07 05 01.2   +05 23 14    13.280   12.940   68.2    4.1   104   25.9 
2024-05-01 00:00 UT   07 05 06.5   +05 24 53    13.301   12.946   67.3    4.1   104   25.9 
2024-05-02 00:00 UT   07 05 12.0   +05 26 31    13.322   12.951   66.4    4.1   104   25.9 
2024-05-03 00:00 UT   07 05 17.7   +05 28 08    13.342   12.957   65.5    4.1   105   25.9 
2024-05-04 00:00 UT   07 05 23.7   +05 29 44    13.363   12.963   64.6    4.0   105   25.9 

    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.