C/2012 S1 (ISON)
ephemeris date magn radius delta ra dec elong phase PA
Perihelion30 Nov 2013-10.30.013 AU0.996 AU16h26m-21°54'0.5°41.1°127°
Nearest approach27 Dec 20136.80.999 AU0.431 AU16h36m+52°27'79.5°75.4°334°
Today18 Oct 202129.223.319 AU23.204 AU07h37m+37°10'95.4°2.4°278°
C/2012 S1 (ISON)- 2021-10-18

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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/2012 S1 (ISON) are:

            e (eccentricity)                : 1.0002660
            q (perihelion distance)         : 0.0126570
            i (inclination)                 : 65.23130
            Ω (Longitude of ascending node) : 294.65330
            ω (Argument of perihelion)      : 346.05400
            L (Longitude of perihelion)     : 288.71372
            B (Latitude of perihelion)      : -12.64069
            T (Time of perihelion passage)  : 2456626.63770

            Epoch                           : 2020 Sep 26
            Reference                       : MPC 89726

            Classification(s):              : Nearly isotropic; New (a > 10000 AU); Sungrazer

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 (8.50 + 5 log[∆] + 8.00 log[r]), whereas the red curve is being recalculated every 6 hours based on the available COBS/MPC observations (currently 8.67 + 5 log[∆] + 10.00 log[r]). The additional green curve shows the effect of forward scattering, occurring when the comet is between the earth and the sun, for a gas-to-dust light ratio δ90 of 0.30. (See Marcus 2007)

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.