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	14 Mar 2026	-	21.502 AU	21.100 AU	13h41m	+66°16'	112.6°	2.4°	214°

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)         : 0.2022460
    i (Inclination)                 : 98.75040
    Ω (Longitude of ascending node) : 170.37840
    ω (Argument of perihelion)      : 255.57510
    L (Longitude of perihelion)     : 139.77658
    B (Latitude of perihelion)      : -73.17680
    T (Time of perihelion passage)  : 2458347.34890

    Epoch                           : 2026 Mar 13
    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
2026-03-13 00:00 UT   13 41 54.8   +66 13 41    21.087   21.494  112.9    2.4   216   32.3 
2026-03-14 00:00 UT   13 41 33.9   +66 15 31    21.095   21.499  112.7    2.4   215   32.3 
2026-03-14 15:59 UT   13 41 19.8   +66 16 42    21.100   21.502  112.6    2.4   214   32.3 
2026-03-15 00:00 UT   13 41 12.7   +66 17 18    21.103   21.504  112.5    2.4   214   32.3 
2026-03-16 00:00 UT   13 40 51.2   +66 19 03    21.111   21.509  112.3    2.5   212   32.3 
2026-03-17 00:00 UT   13 40 29.4   +66 20 45    21.119   21.514  112.1    2.5   211   32.3 
2026-03-18 00:00 UT   13 40 07.4   +66 22 25    21.128   21.520  111.9    2.5   210   32.3 
2026-03-19 00:00 UT   13 39 45.1   +66 24 02    21.136   21.525  111.7    2.5   209   32.3 
2026-03-20 00:00 UT   13 39 22.5   +66 25 36    21.145   21.530  111.5    2.5   208   32.3 
2026-03-21 00:00 UT   13 38 59.8   +66 27 07    21.153   21.535  111.3    2.5   207   32.3 
2026-03-22 00:00 UT   13 38 36.7   +66 28 36    21.162   21.541  111.0    2.5   206   32.3 
2026-03-23 00:00 UT   13 38 13.5   +66 30 03    21.171   21.546  110.8    2.5   204   32.3 
2026-03-24 00:00 UT   13 37 50.1   +66 31 26    21.180   21.551  110.5    2.5   203   32.3 

    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.