C/2018 R5 (Lemmon)
ephemeris	date	magn	radius	delta	ra	dec	elong	phase	PA
Nearest approach	28 Sep 2018	19.5	3.739 AU	2.838 AU	22h49m	+23°02'	150.0°	7.7°	132°
Perihelion	10 Jan 2019	20.2	3.638 AU	4.194 AU	22h43m	-06°33'	49.8°	11.9°	67°
Today	3 Jul 2025	29.0	14.748 AU	14.831 AU	10h27m	-44°25'	83.3°	3.9°	132°

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 R5 (Lemmon) are:

            e (Eccentricity)                : 0.8416980
            q (Perihelion distance)         : 3.6377620
            i (Inclination)                 : 103.68030
            Ω (Longitude of ascending node) : 171.27270
            ω (Argument of perihelion)      : 178.27180
            L (Longitude of perihelion)     : 171.68154
            B (Latitude of perihelion)      : 1.67916
            T (Time of perihelion passage)  : 2458494.28490
            P (Orbital period in years)     : 110.16

            Epoch                           : 2025 Jul 03
            Reference                       : MPC114603

            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 light curve is based on the absolute magnitude and slope parameter as calculated from an MPEC, or the latest values provided by the minor planet center. (11.50 + 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
2025-07-03 00:00 UT   10 26 54.1   -44 27 49    14.816   14.743   83.9    3.9   131   29.0 
2025-07-03 23:45 UT   10 27 07.6   -44 25 10    14.831   14.748   83.3    3.9   132   29.0 
2025-07-04 00:00 UT   10 27 07.7   -44 25 08    14.831   14.748   83.3    3.9   132   29.0 
2025-07-05 00:00 UT   10 27 21.6   -44 22 30    14.846   14.752   82.7    3.9   132   29.0 
2025-07-06 00:00 UT   10 27 35.7   -44 19 55    14.861   14.756   82.1    3.9   133   29.1 
2025-07-07 00:00 UT   10 27 49.9   -44 17 23    14.877   14.760   81.5    3.9   134   29.1 
2025-07-08 00:00 UT   10 28 04.5   -44 14 54    14.892   14.765   80.9    3.9   134   29.1 
2025-07-09 00:00 UT   10 28 19.2   -44 12 28    14.907   14.769   80.2    3.9   135   29.1 
2025-07-10 00:00 UT   10 28 34.1   -44 10 04    14.922   14.773   79.6    3.9   136   29.1 
2025-07-11 00:00 UT   10 28 49.2   -44 07 44    14.937   14.777   79.0    3.9   136   29.1 
2025-07-12 00:00 UT   10 29 04.5   -44 05 26    14.952   14.782   78.4    3.9   137   29.1 
2025-07-13 00:00 UT   10 29 20.0   -44 03 12    14.967   14.786   77.8    3.9   138   29.1 

    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.