C/2020 S8 (Lemmon)
ephemeris	date	magn	radius	delta	ra	dec	elong	phase	PA
Perihelion	10 Apr 2021	15.7	2.355 AU	1.468 AU	15h04m	+15°11'	144.3°	14.4°	231°
Nearest approach	23 Apr 2021	15.7	2.360 AU	1.411 AU	14h10m	+12°37'	154.8°	10.4°	185°
Today	18 Aug 2025	27.9	12.947 AU	13.058 AU	05h21m	-38°57'	81.5°	4.4°	246°

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/2020 S8 (Lemmon) are:

            e (Eccentricity)                : 0.9901130
            q (Perihelion distance)         : 2.3554160
            i (Inclination)                 : 108.54580
            Ω (Longitude of ascending node) : 24.00170
            ω (Argument of perihelion)      : 160.12210
            L (Longitude of perihelion)     : 30.56180
            B (Latitude of perihelion)      : 18.80569
            T (Time of perihelion passage)  : 2459314.82250
            P (Orbital period in years)     : 3677.09

            Epoch                           : 2025 Aug 18
            Reference                       : MPEC 2021-P47

            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 (12.50 + 5 log[∆] + 10.00 log[r]), whereas the red curve is being recalculated every 6 hours based on the available COBS/MPC observations (currently 11.19 + 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
2025-08-18 00:00 UT   05 21 46.2   -38 55 11    13.059   12.942   81.1    4.4   245   27.9 
2025-08-18 20:09 UT   05 21 51.1   -38 57 52    13.058   12.947   81.5    4.4   246   27.9 
2025-08-19 00:00 UT   05 21 52.0   -38 58 23    13.058   12.948   81.5    4.4   246   27.9 
2025-08-20 00:00 UT   05 21 57.5   -39 01 37    13.056   12.954   82.0    4.4   247   27.9 
2025-08-21 00:00 UT   05 22 02.6   -39 04 52    13.054   12.960   82.4    4.4   247   27.9 
2025-08-22 00:00 UT   05 22 07.4   -39 08 10    13.052   12.966   82.9    4.4   248   27.9 
2025-08-23 00:00 UT   05 22 11.8   -39 11 29    13.050   12.972   83.3    4.4   249   27.9 
2025-08-24 00:00 UT   05 22 15.8   -39 14 50    13.048   12.978   83.8    4.4   250   27.9 
2025-08-25 00:00 UT   05 22 19.5   -39 18 12    13.047   12.984   84.2    4.4   251   27.9 
2025-08-26 00:00 UT   05 22 22.8   -39 21 36    13.045   12.990   84.7    4.4   252   27.9 
2025-08-27 00:00 UT   05 22 25.8   -39 25 01    13.043   12.996   85.1    4.4   253   27.9 
2025-08-28 00:00 UT   05 22 28.4   -39 28 28    13.041   13.002   85.6    4.4   253   27.9 

    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.