C/2018 EF9 (Lemmon)
ephemeris date magn radius delta ra dec elong phase PA
Nearest approach13 Mar 201814.81.816 AU1.060 AU14h01m+48°44'124.3°26.9°227°
Perihelion20 May 201815.21.564 AU1.684 AU04h56m+85°13'65.5°36.1°18°
Today29 Mar 202430.616.768 AU17.556 AU00h54m-32°57'36.8°2.0°171°
C/2018 EF9 (Lemmon)- 2024-03-29
astro.vanbuitenen.nl


 
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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 EF9 (Lemmon) are:

            e (Eccentricity)                : 0.9963920
            q (Perihelion distance)         : 1.5637500
            i (Inclination)                 : 84.65510
            Ω (Longitude of ascending node) : 172.58050
            ω (Argument of perihelion)      : 72.64170
            L (Longitude of perihelion)     : 189.17480
            B (Latitude of perihelion)      : 71.86168
            T (Time of perihelion passage)  : 2458258.93940
            P (Orbital period in years)     : 9023.00

            Epoch                           : 2023 Sep 24
            Reference                       : MPEC 2023-CD7

            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 (18.00 + 5 log[∆] + 5.00 log[r]), whereas the red curve is being recalculated every 6 hours based on the available COBS/MPC observations (currently 12.11 + 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
2024-03-29 00:00 UT   00 54 14.2   -32 58 19    17.555   16.766   36.7    2.0   170   30.6 
2024-03-29 10:15 UT   00 54 20.9   -32 57 55    17.556   16.768   36.8    2.0   171   30.6 
2024-03-30 00:00 UT   00 54 29.9   -32 57 23    17.558   16.771   37.0    2.1   172   30.6 
2024-03-31 00:00 UT   00 54 45.7   -32 56 29    17.560   16.777   37.3    2.1   173   30.6 
2024-04-01 00:00 UT   00 55 01.4   -32 55 37    17.563   16.783   37.6    2.1   175   30.6 
2024-04-02 00:00 UT   00 55 17.2   -32 54 47    17.565   16.788   37.9    2.1   176   30.6 
2024-04-03 00:00 UT   00 55 33.0   -32 53 59    17.567   16.794   38.2    2.1   177   30.6 
2024-04-04 00:00 UT   00 55 48.7   -32 53 13    17.569   16.799   38.6    2.1   179   30.6 
2024-04-05 00:00 UT   00 56 04.5   -32 52 29    17.571   16.805   38.9    2.1   180   30.6 
2024-04-06 00:00 UT   00 56 20.3   -32 51 48    17.572   16.811   39.3    2.2   182   30.6 
2024-04-07 00:00 UT   00 56 36.0   -32 51 08    17.574   16.816   39.7    2.2   183   30.6 
2024-04-08 00:00 UT   00 56 51.8   -32 50 30    17.575   16.822   40.1    2.2   184   30.6 


    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.