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	24 Apr 2025	-	19.771 AU	19.572 AU	13h21m	+66°38'	99.9°	2.9°	168°

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/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)
        

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 (12.90 + 5 log[∆] + 10.00 log[r]), whereas the red curve is being recalculated every 6 hours based on the available COBS/MPC observations (currently 9.21 + 5 log[∆] + 12.34 log[r]). The additional green curve shows the effect of forward scattering, occurring when the comet is between the earth and the sun, for a gas-to-dust light ratio δ90 of 0.30. (See Marcus 2007)

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
2025-04-24 00:00 UT   13 21 16.5   +66 38 52    19.565   19.768  100.2    2.9   169   31.7 
2025-04-24 13:10 UT   13 21 01.7   +66 38 44    19.572   19.771   99.9    2.9   168   31.7 
2025-04-25 00:00 UT   13 20 49.6   +66 38 36    19.577   19.773   99.8    2.9   168   31.7 
2025-04-26 00:00 UT   13 20 22.8   +66 38 18    19.590   19.779   99.4    2.9   167   31.7 
2025-04-27 00:00 UT   13 19 56.1   +66 37 56    19.602   19.784   98.9    2.9   166   31.7 
2025-04-28 00:00 UT   13 19 29.7   +66 37 31    19.615   19.790   98.5    2.9   165   31.7 
2025-04-29 00:00 UT   13 19 03.4   +66 37 02    19.627   19.795   98.1    2.9   164   31.7 
2025-04-30 00:00 UT   13 18 37.3   +66 36 31    19.640   19.801   97.7    2.9   163   31.7 
2025-05-01 00:00 UT   13 18 11.4   +66 35 56    19.653   19.806   97.3    2.9   162   31.7 
2025-05-02 00:00 UT   13 17 45.7   +66 35 19    19.665   19.811   96.8    2.9   161   31.7 
2025-05-03 00:00 UT   13 17 20.2   +66 34 38    19.678   19.817   96.4    2.9   160   31.7 
2025-05-04 00:00 UT   13 16 55.0   +66 33 54    19.691   19.822   96.0    2.9   159   31.7 

    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.