C/2020 H7 (Lemmon)
ephemeris	date	magn	radius	delta	ra	dec	elong	phase	PA
Nearest approach	26 May 2020	20.3	4.420 AU	3.750 AU	16h53m	+32°09'	125.8°	10.7°	192°
Perihelion	2 Jun 2020	20.3	4.420 AU	3.762 AU	16h37m	+32°52'	124.8°	10.9°	178°
Today	14 Jul 2025	28.1	13.603 AU	14.541 AU	08h49m	+08°48'	21.8°	1.6°	128°

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/2020 H7 (Lemmon) are:

            e (Eccentricity)                : 0.9968540
            q (Perihelion distance)         : 4.4195450
            i (Inclination)                 : 135.92350
            Ω (Longitude of ascending node) : 323.51940
            ω (Argument of perihelion)      : 82.67800
            L (Longitude of perihelion)     : 243.65995
            B (Latitude of perihelion)      : 43.62582
            T (Time of perihelion passage)  : 2459003.45090
            P (Orbital period in years)     : 52653.62

            Epoch                           : 
            Reference                       : MPEC 2020-KB7

            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 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. (11.00 + 5 log[∆] + 10.00 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
2025-07-14 00:00 UT   08 49 29.2   +08 49 25    14.531   13.598   22.5    1.6   127   28.1 
2025-07-14 20:55 UT   08 49 39.4   +08 48 19    14.541   13.603   21.8    1.6   128   28.1 
2025-07-15 00:00 UT   08 49 41.0   +08 48 10    14.542   13.603   21.7    1.6   128   28.1 
2025-07-16 00:00 UT   08 49 52.8   +08 46 54    14.553   13.609   20.9    1.5   129   28.2 
2025-07-17 00:00 UT   08 50 04.7   +08 45 38    14.564   13.614   20.0    1.5   130   28.2 
2025-07-18 00:00 UT   08 50 16.6   +08 44 20    14.574   13.619   19.2    1.4   132   28.2 
2025-07-19 00:00 UT   08 50 28.6   +08 43 02    14.585   13.625   18.4    1.4   133   28.2 
2025-07-20 00:00 UT   08 50 40.6   +08 41 43    14.595   13.630   17.7    1.3   134   28.2 
2025-07-21 00:00 UT   08 50 52.7   +08 40 23    14.604   13.636   16.9    1.2   136   28.2 
2025-07-22 00:00 UT   08 51 04.8   +08 39 03    14.614   13.641   16.1    1.2   138   28.2 
2025-07-23 00:00 UT   08 51 17.0   +08 37 42    14.623   13.646   15.4    1.1   140   28.2 
2025-07-24 00:00 UT   08 51 29.2   +08 36 20    14.632   13.652   14.7    1.1   142   28.2 

    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.