P/2024 FG9 (Nanshan-Hahn)
ephemeris	date	magn	radius	delta	ra	dec	elong	phase	PA
Nearest approach	8 Dec 2023	17.9	2.188 AU	1.261 AU	03h05m	+18°05'	153.6°	11.5°	75°
Perihelion	20 May 2024	17.6	1.596 AU	2.041 AU	07h24m	+20°45'	50.2°	29.2°	99°
Today	12 Oct 2025	23.0	3.895 AU	4.219 AU	17h33m	-22°38'	64.5°	13.4°	92°

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 respectively from COBS or the MPC. 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. (14.0 + 5 log[∆] + 10.0 log[r]). An additional green curve will be shown if an increase in apparent brightness can be expected from forward scattering. This happens when a dust-rich comet is 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 P/2024 FG9 (Nanshan-Hahn) are:

    e (Eccentricity)                : 0.5099710
    q (Perihelion distance)         : 1.5964280
    i (Inclination)                 : 1.73120
    Ω (Longitude of ascending node) : 253.04200
    ω (Argument of perihelion)      : 245.93870
    L (Longitude of perihelion)     : 318.97096
    B (Latitude of perihelion)      : -1.58074
    T (Time of perihelion passage)  : 2460450.94200
    P (Orbital period in years)     : 5.88

    Epoch                           : 2025 Oct 11
    Reference                       : MPEC 2024-UA9

    Classification(s):              : Ecliptic; Jupiter family
    Tisserand (Jupiter)             : 2.958

Ephemerides

Date       Time       RA (2000)    DEC (2000)    delta   radius  elong  phase   PA    magn
2025-10-12 00:00 UT   17 32 58.9   -22 38 09     4.203    3.891   65.2   13.5    92   23.0 
2025-10-12 21:32 UT   17 33 46.9   -22 38 39     4.219    3.895   64.5   13.4    92   23.0 
2025-10-13 00:00 UT   17 33 52.4   -22 38 42     4.221    3.895   64.4   13.4    92   23.0 
2025-10-14 00:00 UT   17 34 46.3   -22 39 13     4.238    3.899   63.6   13.3    92   23.0 
2025-10-15 00:00 UT   17 35 40.8   -22 39 44     4.255    3.903   62.9   13.1    92   23.1 
2025-10-16 00:00 UT   17 36 35.7   -22 40 14     4.273    3.906   62.1   13.0    92   23.1 
2025-10-17 00:00 UT   17 37 31.1   -22 40 42     4.290    3.910   61.3   12.9    92   23.1 
2025-10-18 00:00 UT   17 38 26.9   -22 41 10     4.307    3.914   60.5   12.8    92   23.1 
2025-10-19 00:00 UT   17 39 23.2   -22 41 37     4.324    3.918   59.7   12.7    92   23.1 
2025-10-20 00:00 UT   17 40 20.0   -22 42 02     4.341    3.921   59.0   12.6    92   23.1 
2025-10-21 00:00 UT   17 41 17.1   -22 42 27     4.357    3.925   58.2   12.4    91   23.1 
2025-10-22 00:00 UT   17 42 14.7   -22 42 50     4.374    3.929   57.4   12.3    91   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.