C/2021 F1 (Lemmon-PANSTARRS)
ephemeris	date	magn	radius	delta	ra	dec	elong	phase	PA
Nearest approach	12 Feb 2022	10.9	1.336 AU	1.416 AU	20h29m	+48°54'	64.7°	41.9°	340°
Perihelion	6 Apr 2022	9.6	1.000 AU	1.904 AU	01h06m	+24°18'	17.8°	17.9°	5°
Today	15 Sep 2025	29.6	11.837 AU	12.083 AU	12h11m	-70°25'	73.5°	4.7°	170°

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.)

The orbital elements of C/2021 F1 (Lemmon-PANSTARRS) are:

            e (Eccentricity)                : 0.9959910
            q (Perihelion distance)         : 0.9995040
            i (Inclination)                 : 107.28370
            Ω (Longitude of ascending node) : 203.56660
            ω (Argument of perihelion)      : 146.95680
            L (Longitude of perihelion)     : 214.50472
            B (Latitude of perihelion)      : 31.37584
            T (Time of perihelion passage)  : 2459676.23980
            P (Orbital period in years)     : 3936.61

            Epoch                           : 2025 Sep 15
            Reference                       : MPEC 2022-QD9

            Classification(s):              : Nearly isotropic; Returning (a < 10000 AU); External (P > 200 years)
        

The light curve chart below shows the estimated development of the comet's magnitude. Blue and black dots are visual and photometric CCD observations respectively from COBS or the MPC. The gray curve is based on the absolute magnitude and slope parameter as calculated from the original MPEC, or the latest values provided by the MPC (13.50 + 5 log[∆] + 10.00 log[r]), whereas the red curve is being recalculated every 6 hours based on the available COBS/MPC observations (currently 8.25 + 5 log[∆] + 14.84 log[r]).

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.
A more printer-friendly version of the same chart can be found further down this page as well.

The following chart shows the current location of the comet in a smaller, upside-down telescopic field of view.

A printable version of the short-term path of the comet in a field of view that is optimized for (~10x50) binoculars and finderscopes.

Ephemerides:

Date       Time       RA (2000)    DEC (2000)    delta   radius  elong  phase   PA    magn
2025-09-15 00:00 UT   12 11 08.2   -70 25 32    12.070   11.831   73.9    4.7   170   29.6 
2025-09-15 22:19 UT   12 11 59.6   -70 25 05    12.083   11.837   73.5    4.7   170   29.6 
2025-09-16 00:00 UT   12 12 03.5   -70 25 03    12.084   11.837   73.5    4.7   170   29.6 
2025-09-17 00:00 UT   12 12 58.8   -70 24 38    12.098   11.844   73.0    4.7   171   29.6 
2025-09-18 00:00 UT   12 13 54.1   -70 24 16    12.112   11.851   72.6    4.6   172   29.6 
2025-09-19 00:00 UT   12 14 49.3   -70 23 58    12.126   11.857   72.2    4.6   172   29.6 
2025-09-20 00:00 UT   12 15 44.6   -70 23 44    12.140   11.864   71.8    4.6   173   29.6 
2025-09-21 00:00 UT   12 16 39.8   -70 23 33    12.153   11.871   71.3    4.6   174   29.6 
2025-09-22 00:00 UT   12 17 35.0   -70 23 26    12.167   11.877   70.9    4.6   174   29.6 
2025-09-23 00:00 UT   12 18 30.2   -70 23 23    12.181   11.884   70.5    4.6   175   29.6 
2025-09-24 00:00 UT   12 19 25.3   -70 23 23    12.194   11.891   70.1    4.6   176   29.6 
2025-09-25 00:00 UT   12 20 20.3   -70 23 27    12.208   11.897   69.7    4.5   176   29.6 

    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.