C/2021 U4 (Leonard)
ephemeris	date	magn	radius	delta	ra	dec	elong	phase	PA
Nearest approach	31 Oct 2021	19.7	1.899 AU	0.958 AU	02h36m	-12°00'	153.5°	13.5°	353°
Today	9 Dec 2021	20.6	1.794 AU	1.627 AU	23h22m	-28°48'	82.9°	33.0°	68°
Perihelion	21 Dec 2021	21.0	1.787 AU	1.931 AU	23h01m	-28°53'	66.7°	30.4°	75°

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 U4 (Leonard) are:

            e (eccentricity)                : 0.9601140
            q (perihelion distance)         : 1.7874290
            i (inclination)                 : 152.87720
            Ω (Longitude of ascending node) : 241.80270
            ω (Argument of perihelion)      : 237.27850
            L (Longitude of perihelion)     : 187.62843
            B (Latitude of perihelion)      : -22.55385
            T (Time of perihelion passage)  : 2459570.44480
            P (Orbital period in years)     : 299.99

            Epoch                           : 2021 Dec 08
            Reference                       : MPEC 2021-W31

            Classification(s):              : Nearly isotropic; External (a < 10000 AU)
        

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 the original MPEC, or the latest values provided by the minor planet center. (17.00 + 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.