C/2020 F7 (Lemmon)
ephemeris	date	magn	radius	delta	ra	dec	elong	phase	PA
Nearest approach	15 Feb 2021	18.0	5.702 AU	4.782 AU	08h58m	-06°13'	156.5°	4.0°	36°
Perihelion	14 Nov 2021	17.9	5.337 AU	5.376 AU	09h05m	-33°37'	82.5°	10.6°	287°
Today	4 Jun 2026	23.3	12.263 AU	12.024 AU	23h13m	-43°27'	101.3°	4.7°	250°

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)                : 0.9912390
    q (Perihelion distance)         : 5.3373750
    i (Inclination)                 : 93.99950
    Ω (Longitude of ascending node) : 321.80850
    ω (Argument of perihelion)      : 228.02540
    L (Longitude of perihelion)     : 317.37512
    B (Latitude of perihelion)      : -47.87053
    T (Time of perihelion passage)  : 2459532.89260
    P (Orbital period in years)     : 15036.99

    Epoch                           : 2026 Jun 04
    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
2026-06-03 00:00 UT   23 13 16.0   -43 24 10    12.040   12.253   99.8    4.7   249   23.3 
2026-06-04 00:00 UT   23 13 13.4   -43 26 01    12.031   12.258  100.6    4.7   249   23.3 
2026-06-04 21:08 UT   23 13 10.7   -43 27 40    12.024   12.263  101.3    4.7   250   23.3 
2026-06-05 00:00 UT   23 13 10.3   -43 27 54    12.023   12.264  101.4    4.7   250   23.3 
2026-06-06 00:00 UT   23 13 06.8   -43 29 49    12.015   12.269  102.2    4.6   250   23.3 
2026-06-07 00:00 UT   23 13 02.9   -43 31 45    12.006   12.274  103.0    4.6   251   23.3 
2026-06-08 00:00 UT   23 12 58.6   -43 33 44    11.998   12.279  103.8    4.6   251   23.3 
2026-06-09 00:00 UT   23 12 53.8   -43 35 44    11.990   12.284  104.5    4.6   252   23.3 
2026-06-10 00:00 UT   23 12 48.6   -43 37 45    11.981   12.289  105.3    4.6   253   23.3 
2026-06-11 00:00 UT   23 12 43.0   -43 39 48    11.973   12.295  106.1    4.5   253   23.3 
2026-06-12 00:00 UT   23 12 36.9   -43 41 53    11.965   12.300  106.9    4.5   254   23.3 
2026-06-13 00:00 UT   23 12 30.4   -43 43 59    11.957   12.305  107.7    4.5   255   23.3 
2026-06-14 00:00 UT   23 12 23.4   -43 46 07    11.950   12.310  108.5    4.5   255   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.