C/2023 X4 (Hogan)
ephemeris	date	magn	radius	delta	ra	dec	elong	phase	PA
Nearest approach	11 Jan 2024	20.0	3.782 AU	2.829 AU	07h06m	+37°49'	163.2°	4.3°	161°
Perihelion	25 May 2024	20.7	3.659 AU	4.175 AU	08h03m	+30°35'	53.2°	12.8°	94°
Today	14 Nov 2025	23.0	5.154 AU	6.054 AU	13h49m	-10°32'	22.5°	4.2°	292°

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. (12.0 + 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/2023 X4 (Hogan) are:

    e (Eccentricity)                : 0.6314240
    q (Perihelion distance)         : 3.6589320
    i (Inclination)                 : 11.59230
    Ω (Longitude of ascending node) : 28.77060
    ω (Argument of perihelion)      : 100.61200
    L (Longitude of perihelion)     : -50.40160
    B (Latitude of perihelion)      : 11.39136
    T (Time of perihelion passage)  : 2460455.68120
    P (Orbital period in years)     : 31.28

    Epoch                           : 2025 Nov 13
    Reference                       : MPC184411

    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
2025-11-13 00:00 UT   13 48 25.8   -10 26 33     6.056    5.149   21.6    4.1   292   23.0 
2025-11-14 00:00 UT   13 49 15.7   -10 32 08     6.054    5.153   22.4    4.2   292   23.0 
2025-11-14 03:14 UT   13 49 22.5   -10 32 53     6.054    5.154   22.5    4.2   292   23.0 
2025-11-15 00:00 UT   13 50 05.5   -10 37 41     6.052    5.157   23.2    4.3   292   23.0 
2025-11-16 00:00 UT   13 50 55.0   -10 43 13     6.050    5.162   24.0    4.5   292   23.0 
2025-11-17 00:00 UT   13 51 44.4   -10 48 42     6.047    5.166   24.7    4.6   292   23.0 
2025-11-18 00:00 UT   13 52 33.6   -10 54 10     6.045    5.170   25.5    4.7   292   23.0 
2025-11-19 00:00 UT   13 53 22.5   -10 59 37     6.042    5.175   26.3    4.9   292   23.0 
2025-11-20 00:00 UT   13 54 11.3   -11 05 01     6.039    5.179   27.1    5.0   292   23.0 
2025-11-21 00:00 UT   13 54 59.8   -11 10 23     6.035    5.183   27.9    5.1   291   23.0 
2025-11-22 00:00 UT   13 55 48.1   -11 15 44     6.032    5.187   28.7    5.2   291   23.1 
2025-11-23 00:00 UT   13 56 36.2   -11 21 03     6.028    5.192   29.5    5.4   291   23.1 
2025-11-24 00:00 UT   13 57 24.1   -11 26 19     6.025    5.196   30.3    5.5   291   23.1 

    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.