C/2017 S3 (PANSTARRS) - DISINTEGRATED
ephemeris	date	magn	radius	delta	ra	dec	elong	phase	PA
Disintegration	26 Jul 2018	7.3	0.712 AU	0.947 AU	05h59m	+51°59'	42.4°	74.0°	307°
Nearest approach	7 Aug 2018	5.3	0.383 AU	0.754 AU	08h01m	+26°11'	18.5°	122.9°	299°
Perihelion	16 Aug 2018	-	0.202 AU	0.973 AU	09h29m	+02°42'	11.5°	95.4°	198°
Today	8 May 2026	-	21.789 AU	21.694 AU	13h19m	+66°42'	94.1°	2.6°	156°

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 9.2 + 5 log[∆] + 12.3 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/2017 S3 (PANSTARRS) are:

    e (Eccentricity)                : 1.0000860
    q (Perihelion distance)         : 0.2022550
    i (Inclination)                 : 98.74910
    Ω (Longitude of ascending node) : 170.37560
    ω (Argument of perihelion)      : 255.57490
    L (Longitude of perihelion)     : 139.77785
    B (Latitude of perihelion)      : -73.17729
    T (Time of perihelion passage)  : 2458347.34350

    Epoch                           : 2026 Mar 16
    Reference                       : MPEC 2026-E44

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

Ephemerides

Date       Time       RA (2000)    DEC (2000)    delta   radius  elong  phase   PA    magn
2026-05-07 00:00 UT   13 19 42.2   +66 43 59    21.673   21.781   94.8    2.6   157   32.4 
2026-05-08 00:00 UT   13 19 19.6   +66 43 11    21.685   21.786   94.4    2.6   156   32.4 
2026-05-08 15:55 UT   13 19 04.8   +66 42 38    21.694   21.789   94.1    2.6   156   32.4 
2026-05-09 00:00 UT   13 18 57.3   +66 42 20    21.698   21.791   93.9    2.6   155   32.4 
2026-05-10 00:00 UT   13 18 35.2   +66 41 27    21.711   21.796   93.5    2.7   154   32.4 
2026-05-11 00:00 UT   13 18 13.4   +66 40 30    21.723   21.801   93.1    2.7   153   32.4 
2026-05-12 00:00 UT   13 17 51.8   +66 39 32    21.736   21.807   92.6    2.7   152   32.4 
2026-05-13 00:00 UT   13 17 30.5   +66 38 30    21.749   21.812   92.2    2.7   152   32.4 
2026-05-14 00:00 UT   13 17 09.5   +66 37 27    21.762   21.817   91.8    2.7   151   32.4 
2026-05-15 00:00 UT   13 16 48.8   +66 36 20    21.774   21.822   91.3    2.7   150   32.4 
2026-05-16 00:00 UT   13 16 28.3   +66 35 11    21.787   21.827   90.9    2.7   149   32.4 
2026-05-17 00:00 UT   13 16 08.2   +66 34 00    21.800   21.833   90.5    2.7   148   32.4 
2026-05-18 00:00 UT   13 15 48.3   +66 32 47    21.813   21.838   90.0    2.7   147   32.4 

    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.