C/2020 F7 (Lemmon)
ephemeris	date	magn	radius	delta	ra	dec	elong	phase	PA
Nearest approach	15 Feb 2021	18.0	5.702 AU	4.783 AU	08h58m	-06°13'	156.5°	4.0°	36°
Perihelion	14 Nov 2021	17.9	5.338 AU	5.376 AU	09h05m	-33°37'	82.5°	10.6°	287°
Today	3 Jul 2026	23.3	12.409 AU	11.824 AU	23h08m	-44°29'	123.1°	3.9°	269°

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. 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. (7.0 + 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 F7 (Lemmon) are:

    e (Eccentricity)                : 0.9912960
    q (Perihelion distance)         : 5.3375780
    i (Inclination)                 : 93.99990
    Ω (Longitude of ascending node) : 321.80820
    ω (Argument of perihelion)      : 228.02920
    L (Longitude of perihelion)     : 317.37379
    B (Latitude of perihelion)      : -47.87427
    T (Time of perihelion passage)  : 2459532.94930
    P (Orbital period in years)     : 15185.81

    Epoch                           : 2026 Jul 02
    Reference                       : MPC194166

    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
2026-07-02 00:00 UT   23 09 03.4   -44 27 11    11.829   12.403  122.4    4.0   268   23.3 
2026-07-03 00:00 UT   23 08 48.2   -44 29 33    11.824   12.409  123.1    3.9   269   23.3 
2026-07-03 00:23 UT   23 08 47.9   -44 29 35    11.824   12.409  123.1    3.9   269   23.3 
2026-07-04 00:00 UT   23 08 32.5   -44 31 54    11.819   12.414  123.8    3.9   270   23.3 
2026-07-05 00:00 UT   23 08 16.5   -44 34 16    11.814   12.419  124.5    3.9   271   23.3 
2026-07-06 00:00 UT   23 07 60.0   -44 36 38    11.809   12.424  125.3    3.8   272   23.3 
2026-07-07 00:00 UT   23 07 43.1   -44 38 60    11.804   12.429  126.0    3.8   273   23.3 
2026-07-08 00:00 UT   23 07 25.7   -44 41 21    11.800   12.434  126.7    3.8   274   23.3 
2026-07-09 00:00 UT   23 07 08.0   -44 43 42    11.796   12.440  127.4    3.7   275   23.3 
2026-07-10 00:00 UT   23 06 49.8   -44 46 03    11.792   12.445  128.1    3.7   276   23.3 
2026-07-11 00:00 UT   23 06 31.3   -44 48 23    11.788   12.450  128.8    3.6   277   23.3 
2026-07-12 00:00 UT   23 06 12.3   -44 50 43    11.784   12.455  129.5    3.6   278   23.3 
2026-07-13 00:00 UT   23 05 53.0   -44 53 02    11.780   12.460  130.1    3.6   279   23.3 

    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.