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	12 Aug 2026	28.9	15.035 AU	15.159 AU	05h01m	-36°50'	81.1°	3.8°	243°

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
2026-08-11 00:00 UT   05 01 03.3   -36 47 09    15.162   15.029   80.5    3.8   242   28.9 
2026-08-12 00:00 UT   05 01 09.4   -36 49 44    15.159   15.034   81.0    3.8   243   28.9 
2026-08-12 04:44 UT   05 01 10.6   -36 50 15    15.159   15.035   81.1    3.8   243   28.9 
2026-08-13 00:00 UT   05 01 15.2   -36 52 21    15.156   15.040   81.5    3.8   244   28.9 
2026-08-14 00:00 UT   05 01 20.7   -36 55 00    15.153   15.046   82.0    3.8   245   28.9 
2026-08-15 00:00 UT   05 01 25.9   -36 57 41    15.151   15.051   82.4    3.8   246   28.9 
2026-08-16 00:00 UT   05 01 30.9   -37 00 23    15.148   15.057   82.9    3.8   247   28.9 
2026-08-17 00:00 UT   05 01 35.5   -37 03 07    15.145   15.063   83.4    3.8   247   28.9 
2026-08-18 00:00 UT   05 01 39.9   -37 05 52    15.142   15.068   83.9    3.8   248   28.9 
2026-08-19 00:00 UT   05 01 43.9   -37 08 39    15.139   15.074   84.4    3.8   249   28.9 
2026-08-20 00:00 UT   05 01 47.7   -37 11 27    15.136   15.079   84.9    3.8   250   28.9 
2026-08-21 00:00 UT   05 01 51.1   -37 14 17    15.133   15.085   85.3    3.8   251   28.9 
2026-08-22 00:00 UT   05 01 54.2   -37 17 08    15.130   15.091   85.8    3.8   252   28.9 

    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.