ephemeris date magn radius delta ra dec elong phase PA
Today22 Apr 202428.05.049 AU5.921 AU00h38m-05°53'27.3°5.2°228°
Perihelion22 Sep 202614.92.157 AU3.054 AU11h01m+17°32'22.1°10.1°320°
Nearest approach17 Apr 202716.42.652 AU1.675 AU14h47m-12°08'163.3°6.2°274°
123P/West-Hartley- 2024-04-22

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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 123P/West-Hartley are:

            e (Eccentricity)                : 0.4443000
            q (Perihelion distance)         : 2.1570360
            i (Inclination)                 : 15.28010
            Ω (Longitude of ascending node) : 45.90190
            ω (Argument of perihelion)      : 104.01600
            L (Longitude of perihelion)     : -29.58978
            B (Latitude of perihelion)      : 14.81459
            T (Time of perihelion passage)  : 2461306.13140
            P (Orbital period in years)     : 7.65

            Epoch                           : 2024 Apr 21
            Reference                       : MPEC 2021-F20

            Classification(s):              : Ecliptic; Jupiter family
            Tisserand (Jupiter)             : 2.833

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 (12.20 + 5 log[∆] + 10.00 log[r]), whereas the red curve is being recalculated every 6 hours based on the available COBS/MPC observations (currently 1.93 + 5 log[∆] + 31.52 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.