C/2017 S3 (PANSTARRS) - DISINTEGRATED
ephemeris	date	magn	radius	delta	ra	dec	elong	phase	PA
Disintegration	26 Jul 2018	7.3	0.717 AU	0.957 AU	05h57m	+51°45'	42.5°	73.1°	306°
Nearest approach	7 Aug 2018	5.2	0.381 AU	0.756 AU	08h02m	+25°45'	18.5°	122.6°	297°
Perihelion	17 Aug 2018	-	0.203 AU	0.973 AU	09h30m	+02°33'	11.5°	95.4°	197°
Today	14 Nov 2025	-	20.869 AU	20.976 AU	13h37m	+61°38'	82.4°	2.7°	336°

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)                : 1.0000970
    q (Perihelion distance)         : 0.2034580
    i (Inclination)                 : 99.14200
    Ω (Longitude of ascending node) : 171.18370
    ω (Argument of perihelion)      : 255.74140
    L (Longitude of perihelion)     : 139.16986
    B (Latitude of perihelion)      : -73.11366
    T (Time of perihelion passage)  : 2458347.56100

    Epoch                           : 2023 Sep 24
    Reference                       : MPC114599

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

Ephemerides

Date       Time       RA (2000)    DEC (2000)    delta   radius  elong  phase   PA    magn
2025-11-13 00:00 UT   13 37 21.1   +61 37 16    20.980   20.861   81.7    2.7   337   32.1 
2025-11-14 00:00 UT   13 37 41.6   +61 38 15    20.977   20.866   82.2    2.7   336   32.1 
2025-11-14 13:18 UT   13 37 52.9   +61 38 48    20.976   20.869   82.4    2.7   336   32.1 
2025-11-15 00:00 UT   13 38 01.9   +61 39 16    20.975   20.871   82.6    2.7   336   32.1 
2025-11-16 00:00 UT   13 38 22.1   +61 40 19    20.972   20.877   83.1    2.7   335   32.1 
2025-11-17 00:00 UT   13 38 42.1   +61 41 26    20.970   20.882   83.5    2.7   334   32.1 
2025-11-18 00:00 UT   13 39 02.0   +61 42 35    20.967   20.887   84.0    2.7   333   32.1 
2025-11-19 00:00 UT   13 39 21.8   +61 43 46    20.965   20.893   84.4    2.7   332   32.1 
2025-11-20 00:00 UT   13 39 41.3   +61 44 60    20.962   20.898   84.9    2.7   331   32.1 
2025-11-21 00:00 UT   13 40 00.7   +61 46 16    20.959   20.903   85.3    2.7   331   32.1 
2025-11-22 00:00 UT   13 40 20.0   +61 47 34    20.957   20.909   85.8    2.7   330   32.1 
2025-11-23 00:00 UT   13 40 39.0   +61 48 55    20.954   20.914   86.3    2.7   329   32.1 
2025-11-24 00:00 UT   13 40 57.9   +61 50 19    20.952   20.919   86.7    2.7   328   32.1 

    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.