C/2018 X2 (Fitzsimmons)
ephemeris	date	magn	radius	delta	ra	dec	elong	phase	PA
Nearest approach	5 Jan 2019	18.0	2.986 AU	2.253 AU	03h31m	+51°18'	130.5°	14.5°	105°
Perihelion	10 Jul 2019	16.5	2.111 AU	2.989 AU	09h05m	+21°46'	25.0°	11.7°	96°
Today	6 Jul 2026	33.3	18.363 AU	17.406 AU	19h25m	-42°23'	159.7°	1.1°	344°

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. This lightcurve is being recalculated every 6 hours based on the available COBS/MPC observations (currently 9.7 + 5 log[∆] + 13.8 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 X2 (Fitzsimmons) are:

    e (Eccentricity)                : 0.9852370
    q (Perihelion distance)         : 2.1108120
    i (Inclination)                 : 23.12590
    Ω (Longitude of ascending node) : 340.56080
    ω (Argument of perihelion)      : 162.09310
    L (Longitude of perihelion)     : 324.01100
    B (Latitude of perihelion)      : 6.93598
    T (Time of perihelion passage)  : 2458675.20720
    P (Orbital period in years)     : 1709.67

    Epoch                           : 2026 May 29
    Reference                       : MPC194158

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

Ephemerides

Date       Time       RA (2000)    DEC (2000)    delta   radius  elong  phase   PA    magn
2026-07-05 00:00 UT   19 25 39.3   -42 22 52    17.398   18.354  159.4    1.1   340   33.3 
2026-07-06 00:00 UT   19 25 23.3   -42 23 17    17.402   18.359  159.6    1.1   342   33.3 
2026-07-06 17:22 UT   19 25 11.8   -42 23 35    17.406   18.363  159.7    1.1   344   33.3 
2026-07-07 00:00 UT   19 25 07.4   -42 23 42    17.407   18.364  159.7    1.1   345   33.3 
2026-07-08 00:00 UT   19 24 51.4   -42 24 04    17.412   18.370  159.8    1.1   348   33.4 
2026-07-09 00:00 UT   19 24 35.4   -42 24 26    17.417   18.375  159.8    1.1   351   33.4 
2026-07-10 00:00 UT   19 24 19.4   -42 24 46    17.422   18.380  159.8    1.1   354   33.4 
2026-07-11 00:00 UT   19 24 03.4   -42 25 05    17.427   18.385  159.7    1.1   357   33.4 
2026-07-12 00:00 UT   19 23 47.4   -42 25 23    17.433   18.390  159.6    1.1   360   33.4 
2026-07-13 00:00 UT   19 23 31.4   -42 25 39    17.439   18.395  159.5    1.1     3   33.4 
2026-07-14 00:00 UT   19 23 15.4   -42 25 54    17.446   18.400  159.3    1.1     6   33.4 
2026-07-15 00:00 UT   19 22 59.5   -42 26 08    17.452   18.406  159.0    1.1     8   33.4 
2026-07-16 00:00 UT   19 22 43.5   -42 26 20    17.459   18.411  158.7    1.1    11   33.4 

    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.