C/2021 U4 (Leonard)
ephemeris date magn radius delta ra dec elong phase PA
Nearest approach31 Oct 202119.71.900 AU0.959 AU02h36m-12°00'153.5°13.5°353°
Perihelion21 Dec 202121.01.788 AU1.932 AU23h01m-28°53'66.7°30.3°75°
Today2 Jun 202328.05.777 AU4.766 AU16h25m-26°25'174.5°1.0°41°
C/2021 U4 (Leonard)- 2023-06-02
astro.vanbuitenen.nl


 
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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)                : 0.9601350
            q (Perihelion distance)         : 1.7882080
            i (Inclination)                 : 152.88230
            Ω (Longitude of ascending node) : 241.80920
            ω (Argument of perihelion)      : 237.30270
            L (Longitude of perihelion)     : 187.60843
            B (Latitude of perihelion)      : -22.55617
            T (Time of perihelion passage)  : 2459570.44870
            P (Orbital period in years)     : 300.43

            Epoch                           : 2023 Jun 02
            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.