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	21 Oct 2026	29.0	15.430 AU	15.021 AU	04h54m	-40°13'	112.5°	3.4°	308°

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
2026-10-20 00:00 UT   04 55 10.7   -40 10 23    15.020   15.422  112.1    3.4   306   29.0 
2026-10-21 00:00 UT   04 54 54.1   -40 12 45    15.021   15.428  112.4    3.4   307   29.0 
2026-10-21 08:40 UT   04 54 48.0   -40 13 36    15.021   15.430  112.5    3.4   308   29.0 
2026-10-22 00:00 UT   04 54 37.1   -40 15 05    15.022   15.433  112.7    3.4   308   29.0 
2026-10-23 00:00 UT   04 54 19.9   -40 17 22    15.023   15.439  113.0    3.4   309   29.0 
2026-10-24 00:00 UT   04 54 02.5   -40 19 36    15.024   15.445  113.3    3.4   311   29.0 
2026-10-25 00:00 UT   04 53 44.7   -40 21 48    15.025   15.450  113.6    3.4   312   29.0 
2026-10-26 00:00 UT   04 53 26.7   -40 23 58    15.027   15.456  113.8    3.4   313   29.0 
2026-10-27 00:00 UT   04 53 08.4   -40 26 04    15.028   15.461  114.1    3.4   314   29.0 
2026-10-28 00:00 UT   04 52 49.9   -40 28 08    15.030   15.467  114.4    3.4   315   29.0 
2026-10-29 00:00 UT   04 52 31.2   -40 30 09    15.032   15.473  114.6    3.3   316   29.0 
2026-10-30 00:00 UT   04 52 12.2   -40 32 07    15.034   15.478  114.8    3.3   317   29.0 
2026-10-31 00:00 UT   04 51 52.9   -40 34 02    15.036   15.484  115.1    3.3   319   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.