65P/Gunn
ephemeris	date	magn	radius	delta	ra	dec	elong	phase	PA
Perihelion	16 Jun 2025	17.1	2.926 AU	1.941 AU	18h49m	-30°37'	162.5°	6.0°	290°
Nearest approach	29 Jun 2025	17.1	2.926 AU	1.917 AU	18h39m	-31°29'	171.6°	2.9°	351°
Today	26 Sep 2026	18.7	3.619 AU	2.630 AU	00h32m	-08°14'	169.2°	3.0°	331°

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 11.0 + 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 65P/Gunn are:

    e (Eccentricity)                : 0.2480800
    q (Perihelion distance)         : 2.9255470
    i (Inclination)                 : 9.17520
    Ω (Longitude of ascending node) : 61.96120
    ω (Argument of perihelion)      : 213.60000
    L (Longitude of perihelion)     : 95.22198
    B (Latitude of perihelion)      : -5.06239
    T (Time of perihelion passage)  : 2460842.60160
    P (Orbital period in years)     : 7.67

    Epoch                           : 2026 Sep 25
    Reference                       : MPC xxxxx

    Classification(s):              : Ecliptic; Jupiter family; Quasi-Hilda
    Tisserand (Jupiter)             : 2.991

Ephemerides

Date       Time       RA (2000)    DEC (2000)    delta   radius  elong  phase   PA    magn
2026-09-25 00:00 UT   00 33 28.9   -08 09 20     2.627    3.616  168.8    3.1   322   18.7 
2026-09-26 00:00 UT   00 32 47.9   -08 12 36     2.629    3.618  169.1    3.0   327   18.7 
2026-09-26 12:53 UT   00 32 25.8   -08 14 20     2.630    3.619  169.2    3.0   331   18.7 
2026-09-27 00:00 UT   00 32 06.8   -08 15 48     2.631    3.620  169.2    3.0   334   18.7 
2026-09-28 00:00 UT   00 31 25.6   -08 18 55     2.633    3.623  169.2    3.0   340   18.7 
2026-09-29 00:00 UT   00 30 44.3   -08 21 58     2.636    3.625  169.1    3.0   346   18.7 
2026-09-30 00:00 UT   00 30 03.1   -08 24 56     2.639    3.627  168.9    3.0   352   18.7 
2026-10-01 00:00 UT   00 29 21.9   -08 27 50     2.642    3.629  168.6    3.1   358   18.7 
2026-10-02 00:00 UT   00 28 40.9   -08 30 38     2.646    3.632  168.1    3.3     3   18.7 
2026-10-03 00:00 UT   00 27 59.9   -08 33 20     2.650    3.634  167.6    3.4     8   18.7 
2026-10-04 00:00 UT   00 27 19.0   -08 35 58     2.654    3.636  167.0    3.6    12   18.7 
2026-10-05 00:00 UT   00 26 38.4   -08 38 29     2.659    3.638  166.3    3.7    16   18.7 
2026-10-06 00:00 UT   00 25 58.0   -08 40 55     2.664    3.641  165.6    3.9    20   18.7 

    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.