C/2025 F2 (SWAN) - DISINTEGRATED
ephemeris	date	magn	radius	delta	ra	dec	elong	phase	PA
Disintegration	16 Apr 2025	8.1	0.543 AU	1.197 AU	00h30m	+32°00'	26.8°	56.4°	322°
Perihelion	1 May 2025	8.4	0.333 AU	0.963 AU	03h33m	+28°15'	19.3°	88.0°	50°
Nearest approach	1 May 2025	8.4	0.334 AU	0.963 AU	03h38m	+27°36'	19.3°	88.0°	53°
Today	31 May 2025	-	0.869 AU	1.366 AU	05h29m	-15°11'	39.5°	47.9°	160°

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.)

The orbital elements of C/2025 F2 (SWAN) are:

            e (Eccentricity)                : 1.0001070
            q (Perihelion distance)         : 0.3334940
            i (Inclination)                 : 90.36490
            Ω (Longitude of ascending node) : 329.84080
            ω (Argument of perihelion)      : 153.83720
            L (Longitude of perihelion)     : 330.02006
            B (Latitude of perihelion)      : 26.16223
            T (Time of perihelion passage)  : 2460796.66150

            Epoch                           : 2025 May 30
            Reference                       : MPEC 2025-J92

            Classification(s):              : Nearly isotropic; New (a > 10000 AU)
        

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 gray curve is based on the absolute magnitude and slope parameter as calculated from the original MPEC, or the latest values provided by the MPC (11.20 + 5 log[∆] + 10.00 log[r]), whereas the red curve is being recalculated every 6 hours based on the available COBS/MPC observations (currently 10.38 + 5 log[∆] + 10.00 log[r]).

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.
A more printer-friendly version of the same chart can be found further down this page as well.

The following chart shows the current location of the comet in a smaller, upside-down telescopic field of view.

A printable version of the short-term path of the comet in a field of view that is optimized for (~10x50) binoculars and finderscopes.

Ephemerides:

Date       Time       RA (2000)    DEC (2000)    delta   radius  elong  phase   PA    magn
2025-05-31 00:00 UT   05 27 47.4   -14 25 25     1.352    0.849   38.9   48.5   159   10.3 
2025-05-31 23:33 UT   05 29 03.5   -15 11 33     1.366    0.869   39.5   47.9   160   10.5 
2025-06-01 00:00 UT   05 29 04.9   -15 12 25     1.366    0.870   39.5   47.9   160   10.5 
2025-06-02 00:00 UT   05 30 21.1   -15 58 12     1.380    0.890   40.1   47.2   161   10.6 
2025-06-03 00:00 UT   05 31 36.0   -16 42 50     1.394    0.911   40.7   46.6   163   10.7 
2025-06-04 00:00 UT   05 32 49.8   -17 26 25     1.407    0.931   41.3   46.1   164   10.8 
2025-06-05 00:00 UT   05 34 02.5   -18 09 01     1.421    0.951   42.0   45.5   165   10.9 
2025-06-06 00:00 UT   05 35 14.4   -18 50 41     1.434    0.971   42.6   45.0   166   11.0 
2025-06-07 00:00 UT   05 36 25.5   -19 31 32     1.447    0.991   43.2   44.5   168   11.1 
2025-06-08 00:00 UT   05 37 35.9   -20 11 35     1.460    1.011   43.8   44.0   169   11.3 
2025-06-09 00:00 UT   05 38 45.6   -20 50 54     1.472    1.031   44.4   43.5   170   11.4 
2025-06-10 00:00 UT   05 39 54.8   -21 29 33     1.485    1.050   45.0   43.1   171   11.5 

    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.