C/2018 X3 (PANSTARRS)
ephemeris	date	magn	radius	delta	ra	dec	elong	phase	PA
Nearest approach	8 Dec 2018	20.0	2.708 AU	1.731 AU	04h46m	+14°40'	171.1°	3.2°	24°
Perihelion	1 Jan 2019	20.1	2.699 AU	1.824 AU	04h21m	+21°26'	146.6°	11.6°	80°
Today	8 Mar 2026	31.9	14.573 AU	14.252 AU	16h05m	+00°58'	107.0°	3.7°	275°

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.)

Light curve

The light curve chart below shows the estimated development of the comet's magnitude. Blue and black dots are visual and photometric CCD observations from COBS. 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. (14.5 + 5 log[∆] + 10.0 log[r]). An additional green curve is displayed when an increase in apparent brightness is expected due to forward scattering of sunlight, which occurs when a dust-rich comet is located between the Earth and the Sun. (See Marcus 2007)

Charts

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.

Orbital elements

The orbital elements of C/2018 X3 (PANSTARRS) are:

    e (Eccentricity)                : 0.7827430
    q (Perihelion distance)         : 2.6994970
    i (Inclination)                 : 43.43440
    Ω (Longitude of ascending node) : 78.78970
    ω (Argument of perihelion)      : 359.93030
    L (Longitude of perihelion)     : 78.73909
    B (Latitude of perihelion)      : -0.04792
    T (Time of perihelion passage)  : 2458485.08280
    P (Orbital period in years)     : 43.80

    Epoch                           : 2026 Mar 07
    Reference                       : MPEC 2026-E44

    Classification(s):              : Nearly isotropic; Returning (a < 10000 AU); Halley type (P < 200 years)

Ephemerides

Date       Time       RA (2000)    DEC (2000)    delta   radius  elong  phase   PA    magn
2026-03-07 00:00 UT   16 05 21.1   +00 57 04    14.267   14.569  105.8    3.8   275   31.9 
2026-03-08 00:00 UT   16 05 19.0   +00 58 15    14.255   14.572  106.8    3.7   275   31.9 
2026-03-08 04:30 UT   16 05 18.5   +00 58 29    14.252   14.573  107.0    3.7   275   31.9 
2026-03-09 00:00 UT   16 05 16.5   +00 59 27    14.243   14.576  107.7    3.7   275   31.9 
2026-03-10 00:00 UT   16 05 13.8   +01 00 39    14.231   14.579  108.7    3.7   274   31.9 
2026-03-11 00:00 UT   16 05 10.7   +01 01 51    14.219   14.582  109.6    3.7   274   31.9 
2026-03-12 00:00 UT   16 05 07.4   +01 03 04    14.207   14.585  110.5    3.7   273   31.9 
2026-03-13 00:00 UT   16 05 03.9   +01 04 17    14.195   14.588  111.5    3.6   273   31.9 
2026-03-14 00:00 UT   16 05 00.0   +01 05 31    14.184   14.591  112.4    3.6   273   31.9 
2026-03-15 00:00 UT   16 04 55.9   +01 06 45    14.172   14.595  113.3    3.6   272   31.9 
2026-03-16 00:00 UT   16 04 51.5   +01 07 59    14.161   14.598  114.3    3.6   272   31.9 
2026-03-17 00:00 UT   16 04 46.8   +01 09 13    14.149   14.601  115.2    3.5   271   31.9 
2026-03-18 00:00 UT   16 04 41.9   +01 10 27    14.138   14.604  116.1    3.5   271   31.9 

    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.