C/2020 F7 (Lemmon)
ephemeris	date	magn	radius	delta	ra	dec	elong	phase	PA
Nearest approach	15 Feb 2021	18.0	5.701 AU	4.782 AU	08h58m	-06°13'	156.5°	4.0°	36°
Perihelion	14 Nov 2021	17.9	5.337 AU	5.377 AU	09h05m	-33°36'	82.4°	10.6°	287°
Today	14 Apr 2026	23.3	11.998 AU	12.443 AU	23h07m	-42°44'	61.5°	4.2°	221°

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)                : 0.9911270
    q (Perihelion distance)         : 5.3369670
    i (Inclination)                 : 93.99760
    Ω (Longitude of ascending node) : 321.80980
    ω (Argument of perihelion)      : 228.01790
    L (Longitude of perihelion)     : 317.37968
    B (Latitude of perihelion)      : -47.86321
    T (Time of perihelion passage)  : 2459532.78470
    P (Orbital period in years)     : 14751.50

    Epoch                           : 2026 Apr 14
    Reference                       : MPEC 2026-E44

    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
2026-04-13 00:00 UT   23 07 20.2   -42 45 10    12.454   11.989   60.3    4.2   220   23.3 
2026-04-14 00:00 UT   23 07 34.9   -42 44 44    12.448   11.994   61.0    4.2   220   23.3 
2026-04-14 17:53 UT   23 07 45.6   -42 44 26    12.443   11.998   61.5    4.2   221   23.3 
2026-04-15 00:00 UT   23 07 49.3   -42 44 20    12.441   11.999   61.7    4.2   221   23.3 
2026-04-16 00:00 UT   23 08 03.5   -42 43 59    12.435   12.004   62.4    4.2   222   23.3 
2026-04-17 00:00 UT   23 08 17.4   -42 43 42    12.429   12.009   63.2    4.3   222   23.3 
2026-04-18 00:00 UT   23 08 31.1   -42 43 28    12.422   12.015   63.9    4.3   223   23.3 
2026-04-19 00:00 UT   23 08 44.6   -42 43 16    12.415   12.020   64.6    4.3   224   23.3 
2026-04-20 00:00 UT   23 08 57.7   -42 43 08    12.408   12.025   65.4    4.4   224   23.3 
2026-04-21 00:00 UT   23 09 10.6   -42 43 03    12.401   12.030   66.1    4.4   225   23.3 
2026-04-22 00:00 UT   23 09 23.3   -42 43 01    12.394   12.035   66.9    4.4   225   23.3 
2026-04-23 00:00 UT   23 09 35.6   -42 43 03    12.387   12.040   67.6    4.4   226   23.3 
2026-04-24 00:00 UT   23 09 47.7   -42 43 07    12.380   12.046   68.4    4.5   227   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.