C/2017 E3 (PANSTARRS)
ephemeris	date	magn	radius	delta	ra	dec	elong	phase	PA
Nearest approach	25 Apr 2017	16.1	5.907 AU	5.046 AU	12h45m	-41°47'	146.0°	5.5°	39°
Perihelion	6 Jun 2017	16.2	5.899 AU	5.296 AU	12h37m	-33°56'	122.2°	8.4°	97°
Today	13 May 2026	27.2	20.005 AU	19.931 AU	19h23m	+50°54'	92.8°	2.9°	236°

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 + 5 log[∆] + 15.2 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 E3 (PANSTARRS) are:

    e (Eccentricity)                : 1.0042510
    q (Perihelion distance)         : 5.8991910
    i (Inclination)                 : 70.66600
    Ω (Longitude of ascending node) : 220.74250
    ω (Argument of perihelion)      : 334.14790
    L (Longitude of perihelion)     : 211.62881
    B (Latitude of perihelion)      : -24.29648
    T (Time of perihelion passage)  : 2457911.41560

    Epoch                           : 2026 May 12
    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
2026-05-12 00:00 UT   19 23 13.1   +50 50 29    19.932   19.998   92.3    2.9   237   27.2 
2026-05-13 00:00 UT   19 23 06.2   +50 52 59    19.931   20.002   92.6    2.9   237   27.2 
2026-05-13 14:55 UT   19 23 01.8   +50 54 32    19.931   20.005   92.8    2.9   236   27.2 
2026-05-14 00:00 UT   19 22 59.1   +50 55 28    19.930   20.007   92.9    2.9   236   27.2 
2026-05-15 00:00 UT   19 22 51.7   +50 57 55    19.930   20.012   93.2    2.9   235   27.2 
2026-05-16 00:00 UT   19 22 44.0   +51 00 21    19.929   20.016   93.5    2.9   234   27.2 
2026-05-17 00:00 UT   19 22 36.1   +51 02 44    19.928   20.021   93.8    2.9   233   27.2 
2026-05-18 00:00 UT   19 22 27.9   +51 05 06    19.928   20.025   94.1    2.9   232   27.2 
2026-05-19 00:00 UT   19 22 19.4   +51 07 26    19.927   20.030   94.4    2.9   231   27.2 
2026-05-20 00:00 UT   19 22 10.6   +51 09 44    19.927   20.035   94.6    2.9   230   27.2 
2026-05-21 00:00 UT   19 22 01.6   +51 11 60    19.926   20.039   94.9    2.9   229   27.2 
2026-05-22 00:00 UT   19 21 52.4   +51 14 14    19.926   20.044   95.2    2.9   228   27.2 
2026-05-23 00:00 UT   19 21 42.9   +51 16 26    19.925   20.048   95.5    2.9   227   27.2 

    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.