C/2018 X3 (PANSTARRS)
ephemeris	date	magn	radius	delta	ra	dec	elong	phase	PA
Nearest approach	8 Dec 2018	20.0	2.710 AU	1.732 AU	04h46m	+14°43'	171.2°	3.2°	24°
Perihelion	1 Jan 2019	20.1	2.701 AU	1.825 AU	04h21m	+21°27'	146.7°	11.5°	80°
Today	15 May 2026	31.9	14.789 AU	13.846 AU	15h53m	+02°09'	158.1°	1.5°	196°

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)                : 0.7826850
    q (Perihelion distance)         : 2.7007520
    i (Inclination)                 : 43.42920
    Ω (Longitude of ascending node) : 78.79420
    ω (Argument of perihelion)      : 359.94010
    L (Longitude of perihelion)     : 78.75070
    B (Latitude of perihelion)      : -0.04118
    T (Time of perihelion passage)  : 2458485.02320
    P (Orbital period in years)     : 43.81

    Epoch                           : 2026 May 14
    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
2026-05-14 00:00 UT   15 54 09.1   +02 08 42    13.842   14.783  157.9    1.5   201   31.9 
2026-05-15 00:00 UT   15 53 54.3   +02 09 13    13.844   14.786  158.0    1.5   198   31.9 
2026-05-15 17:04 UT   15 53 43.7   +02 09 34    13.846   14.789  158.1    1.5   196   31.9 
2026-05-16 00:00 UT   15 53 39.4   +02 09 42    13.847   14.789  158.1    1.5   195   31.9 
2026-05-17 00:00 UT   15 53 24.5   +02 10 10    13.849   14.793  158.1    1.5   193   31.9 
2026-05-18 00:00 UT   15 53 09.5   +02 10 35    13.852   14.796  158.1    1.5   190   31.9 
2026-05-19 00:00 UT   15 52 54.6   +02 10 60    13.856   14.799  158.0    1.5   187   31.9 
2026-05-20 00:00 UT   15 52 39.7   +02 11 22    13.859   14.802  157.9    1.5   184   31.9 
2026-05-21 00:00 UT   15 52 24.7   +02 11 43    13.863   14.805  157.7    1.5   182   31.9 
2026-05-22 00:00 UT   15 52 09.8   +02 12 03    13.867   14.808  157.5    1.5   179   31.9 
2026-05-23 00:00 UT   15 51 54.8   +02 12 20    13.872   14.811  157.3    1.5   176   31.9 
2026-05-24 00:00 UT   15 51 39.9   +02 12 36    13.877   14.814  157.0    1.5   174   31.9 
2026-05-25 00:00 UT   15 51 25.0   +02 12 51    13.882   14.817  156.7    1.6   172   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.