C/2020 B2 (Lemmon)
ephemeris	date	magn	radius	delta	ra	dec	elong	phase	PA
Perihelion	26 Jan 2020	16.0	2.758 AU	2.077 AU	12h33m	+41°33'	124.6°	17.1°	265°
Nearest approach	2 Mar 2020	15.8	2.782 AU	1.892 AU	11h32m	+37°52'	147.9°	10.9°	198°
Today	27 Apr 2024	26.2	12.211 AU	11.850 AU	17h50m	-81°49'	108.7°	4.5°	305°

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 B2 (Lemmon) are:

            e (Eccentricity)                : 0.9592380
            q (Perihelion distance)         : 2.7582220
            i (Inclination)                 : 55.75240
            Ω (Longitude of ascending node) : 354.26330
            ω (Argument of perihelion)      : 143.59400
            L (Longitude of perihelion)     : 331.72480
            B (Latitude of perihelion)      : 29.37987
            T (Time of perihelion passage)  : 2458875.28890
            P (Orbital period in years)     : 556.62

            Epoch                           : 2024 Apr 26
            Reference                       : MPEC 2020-HN5

            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. (10.00 + 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
2024-04-27 00:00 UT   17 50 42.5   -81 48 48    11.851   12.210  108.6    4.5   305   26.2 
2024-04-27 05:06 UT   17 50 29.2   -81 49 29    11.850   12.211  108.7    4.5   305   26.2 
2024-04-28 00:00 UT   17 49 38.8   -81 51 57    11.849   12.215  109.0    4.5   306   26.2 
2024-04-29 00:00 UT   17 48 32.5   -81 55 03    11.848   12.221  109.5    4.5   307   26.2 
2024-04-30 00:00 UT   17 47 23.4   -81 58 04    11.847   12.227  109.9    4.4   309   26.2 
2024-05-01 00:00 UT   17 46 11.8   -82 01 03    11.847   12.233  110.3    4.4   310   26.2 
2024-05-02 00:00 UT   17 44 57.4   -82 03 57    11.846   12.239  110.7    4.4   311   26.2 
2024-05-03 00:00 UT   17 43 40.4   -82 06 48    11.845   12.244  111.1    4.4   312   26.2 
2024-05-04 00:00 UT   17 42 20.8   -82 09 34    11.845   12.250  111.5    4.4   314   26.2 
2024-05-05 00:00 UT   17 40 58.5   -82 12 16    11.844   12.256  111.8    4.4   315   26.3 
2024-05-06 00:00 UT   17 39 33.7   -82 14 54    11.844   12.262  112.2    4.4   316   26.3 
2024-05-07 00:00 UT   17 38 06.2   -82 17 27    11.844   12.267  112.6    4.4   318   26.3 

    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.