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	22 Jun 2025	29.0	14.698 AU	14.651 AU	10h24m	-44°59'	90.6°	4.0°	123°

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)                : 0.8416970
            q (Perihelion distance)         : 3.6378000
            i (Inclination)                 : 103.68150
            Ω (Longitude of ascending node) : 171.27110
            ω (Argument of perihelion)      : 178.27180
            L (Longitude of perihelion)     : 171.67998
            B (Latitude of perihelion)      : 1.67915
            T (Time of perihelion passage)  : 2458494.28130
            P (Orbital period in years)     : 110.16

            Epoch                           : 2025 Jun 21
            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
2025-06-22 00:00 UT   10 24 40.4   -45 00 20    14.647   14.696   90.8    4.0   123   29.0 
2025-06-22 06:25 UT   10 24 43.3   -44 59 28    14.651   14.698   90.6    4.0   123   29.0 
2025-06-23 00:00 UT   10 24 51.2   -44 57 09    14.662   14.701   90.2    4.0   124   29.0 
2025-06-24 00:00 UT   10 25 02.4   -44 54 01    14.678   14.705   89.5    4.0   125   29.0 
2025-06-25 00:00 UT   10 25 13.8   -44 50 55    14.693   14.709   88.9    4.0   125   29.0 
2025-06-26 00:00 UT   10 25 25.4   -44 47 52    14.708   14.714   88.3    4.0   126   29.0 
2025-06-27 00:00 UT   10 25 37.3   -44 44 52    14.724   14.718   87.7    4.0   127   29.0 
2025-06-28 00:00 UT   10 25 49.5   -44 41 55    14.739   14.722   87.0    4.0   127   29.0 
2025-06-29 00:00 UT   10 26 01.9   -44 38 60    14.754   14.726   86.4    4.0   128   29.0 
2025-06-30 00:00 UT   10 26 14.6   -44 36 08    14.770   14.731   85.8    3.9   129   29.0 
2025-07-01 00:00 UT   10 26 27.5   -44 33 19    14.785   14.735   85.2    3.9   129   29.0 
2025-07-02 00:00 UT   10 26 40.7   -44 30 32    14.800   14.739   84.6    3.9   130   29.0 

    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.