C/2018 U1 (Lemmon)
ephemeris date magn radius delta ra dec elong phase PA
Nearest approach18 Jun 202115.25.101 AU4.139 AU17h19m-03°39'159.1°4.1°161°
Perihelion2 Nov 202115.94.991 AU5.830 AU16h32m-22°15'29.5°5.6°99°
Today26 Apr 202418.48.271 AU7.974 AU08h28m-64°37'103.7°6.8°93°
C/2018 U1 (Lemmon)- 2024-04-26
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 U1 (Lemmon) are:

            e (Eccentricity)                : 1.0010250
            q (Perihelion distance)         : 4.9905160
            i (Inclination)                 : 108.32500
            Ω (Longitude of ascending node) : 75.51100
            ω (Argument of perihelion)      : 180.43160
            L (Longitude of perihelion)     : 75.37530
            B (Latitude of perihelion)      : -0.40971
            T (Time of perihelion passage)  : 2459521.28020

            Epoch                           : 2024 Apr 25
            Reference                       : MPEC 2023-N01

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

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 (5.00 + 5 log[∆] + 10.00 log[r]), whereas the red curve is being recalculated every 6 hours based on the available COBS/MPC observations (currently 6.30 + 5 log[∆] + 8.26 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
2024-04-26 00:00 UT   08 28 57.6   -64 39 18     7.973    8.270  103.7    6.8    93   18.4 
2024-04-26 03:41 UT   08 28 55.0   -64 37 53     7.974    8.271  103.7    6.8    93   18.4 
2024-04-27 00:00 UT   08 28 41.7   -64 30 05     7.981    8.275  103.6    6.8    94   18.4 
2024-04-28 00:00 UT   08 28 27.1   -64 20 53     7.989    8.281  103.4    6.8    95   18.4 
2024-04-29 00:00 UT   08 28 13.8   -64 11 42     7.997    8.286  103.2    6.8    96   18.4 
2024-04-30 00:00 UT   08 28 01.8   -64 02 33     8.005    8.291  103.1    6.8    97   18.4 
2024-05-01 00:00 UT   08 27 51.0   -63 53 27     8.014    8.297  102.9    6.8    98   18.4 
2024-05-02 00:00 UT   08 27 41.5   -63 44 22     8.022    8.302  102.7    6.8    99   18.4 
2024-05-03 00:00 UT   08 27 33.2   -63 35 19     8.030    8.307  102.5    6.8   100   18.4 
2024-05-04 00:00 UT   08 27 26.0   -63 26 19     8.039    8.313  102.3    6.8   101   18.4 
2024-05-05 00:00 UT   08 27 20.0   -63 17 21     8.048    8.318  102.1    6.8   102   18.4 
2024-05-06 00:00 UT   08 27 15.2   -63 08 26     8.057    8.323  101.9    6.8   103   18.4 


    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.