C/2020 S8 (Lemmon)
ephemeris	date	magn	radius	delta	ra	dec	elong	phase	PA
Perihelion	10 Apr 2021	15.7	2.356 AU	1.469 AU	15h05m	+15°08'	144.1°	14.4°	232°
Nearest approach	22 Apr 2021	15.7	2.360 AU	1.410 AU	14h10m	+12°33'	154.9°	10.4°	185°
Today	15 Jul 2026	28.8	14.876 AU	15.214 AU	04h56m	-35°50'	68.7°	3.7°	220°

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.)

Light curve

The light curve chart below shows the estimated development of the comet's magnitude. Blue and black dots are visual and photometric CCD observations from COBS. This lightcurve is being recalculated every 6 hours based on the available COBS/MPC observations (currently 11.2 + 5 log[∆] + 10.0 log[r]). An additional green curve is displayed when an increase in apparent brightness is expected due to forward scattering of sunlight, which occurs when a dust-rich comet is located between the Earth and the Sun. (See Marcus 2007)

Charts

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.

Orbital elements

The orbital elements of C/2020 S8 (Lemmon) are:

    e (Eccentricity)                : 0.9899600
    q (Perihelion distance)         : 2.3555200
    i (Inclination)                 : 108.56680
    Ω (Longitude of ascending node) : 23.94660
    ω (Argument of perihelion)      : 160.09570
    L (Longitude of perihelion)     : 30.52319
    B (Latitude of perihelion)      : 18.82815
    T (Time of perihelion passage)  : 2459314.51500
    P (Orbital period in years)     : 3593.60

    Epoch                           : 2026 May 29
    Reference                       : MPC194170

    Classification(s):              : Nearly isotropic; Returning (a < 10000 AU); External (P > 200 years)

Ephemerides

Date       Time       RA (2000)    DEC (2000)    delta   radius  elong  phase   PA    magn
2026-07-14 00:00 UT   04 56 33.5   -35 49 17    15.215   14.870   68.3    3.6   219   28.8 
2026-07-15 00:00 UT   04 56 46.0   -35 50 48    15.214   14.876   68.7    3.6   220   28.8 
2026-07-15 02:05 UT   04 56 47.1   -35 50 56    15.214   14.876   68.7    3.7   220   28.8 
2026-07-16 00:00 UT   04 56 58.4   -35 52 22    15.214   14.881   69.1    3.7   221   28.8 
2026-07-17 00:00 UT   04 57 10.5   -35 53 58    15.212   14.887   69.5    3.7   221   28.8 
2026-07-18 00:00 UT   04 57 22.5   -35 55 37    15.211   14.893   69.9    3.7   222   28.8 
2026-07-19 00:00 UT   04 57 34.2   -35 57 18    15.210   14.898   70.3    3.7   223   28.8 
2026-07-20 00:00 UT   04 57 45.8   -35 59 02    15.209   14.904   70.7    3.7   224   28.8 
2026-07-21 00:00 UT   04 57 57.2   -36 00 49    15.207   14.910   71.1    3.7   225   28.8 
2026-07-22 00:00 UT   04 58 08.3   -36 02 38    15.206   14.915   71.5    3.7   226   28.8 
2026-07-23 00:00 UT   04 58 19.3   -36 04 30    15.204   14.921   71.9    3.7   227   28.8 
2026-07-24 00:00 UT   04 58 30.0   -36 06 24    15.203   14.927   72.4    3.7   227   28.8 
2026-07-25 00:00 UT   04 58 40.5   -36 08 21    15.201   14.932   72.8    3.7   228   28.8 

    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.