C/2020 F7 (Lemmon)
ephemeris	date	magn	radius	delta	ra	dec	elong	phase	PA
Nearest approach	15 Feb 2021	18.0	5.700 AU	4.781 AU	08h58m	-06°14'	156.5°	4.0°	36°
Perihelion	14 Nov 2021	17.9	5.336 AU	5.378 AU	09h05m	-33°34'	82.3°	10.6°	287°
Today	7 Jan 2026	23.0	11.493 AU	12.134 AU	22h38m	-47°02'	47.5°	3.6°	103°

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)                : 0.9909500
    q (Perihelion distance)         : 5.3362380
    i (Inclination)                 : 93.99290
    Ω (Longitude of ascending node) : 321.81330
    ω (Argument of perihelion)      : 228.00530
    L (Longitude of perihelion)     : 317.39031
    B (Latitude of perihelion)      : -47.85104
    T (Time of perihelion passage)  : 2459532.62210
    P (Orbital period in years)     : 14317.92

    Epoch                           : 2026 Jan 07
    Reference                       : MPEC 2024-A43

    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
2026-01-06 00:00 UT   22 37 47.2   -47 10 52    12.109   11.484   48.7    3.7   101   23.0 
2026-01-07 00:00 UT   22 38 00.3   -47 06 22    12.123   11.489   48.0    3.6   102   23.0 
2026-01-07 20:44 UT   22 38 11.9   -47 02 29    12.134   11.493   47.5    3.6   103   23.0 
2026-01-08 00:00 UT   22 38 13.7   -47 01 53    12.136   11.494   47.4    3.6   103   23.0 
2026-01-09 00:00 UT   22 38 27.4   -46 57 25    12.150   11.499   46.8    3.6   104   23.0 
2026-01-10 00:00 UT   22 38 41.5   -46 52 59    12.163   11.504   46.2    3.5   105   23.0 
2026-01-11 00:00 UT   22 38 55.8   -46 48 34    12.176   11.510   45.6    3.5   106   23.0 
2026-01-12 00:00 UT   22 39 10.3   -46 44 11    12.188   11.515   45.0    3.5   107   23.0 
2026-01-13 00:00 UT   22 39 25.2   -46 39 49    12.201   11.520   44.5    3.4   108   23.0 
2026-01-14 00:00 UT   22 39 40.3   -46 35 29    12.213   11.525   43.9    3.4   109   23.1 
2026-01-15 00:00 UT   22 39 55.7   -46 31 11    12.226   11.531   43.3    3.4   111   23.1 
2026-01-16 00:00 UT   22 40 11.3   -46 26 54    12.238   11.536   42.8    3.3   112   23.1 
2026-01-17 00:00 UT   22 40 27.2   -46 22 38    12.250   11.541   42.3    3.3   113   23.1 

    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.