C/2017 E3 (PANSTARRS)
ephemeris	date	magn	radius	delta	ra	dec	elong	phase	PA
Nearest approach	25 Apr 2017	16.2	5.908 AU	5.047 AU	12h45m	-41°46'	146.0°	5.5°	39°
Perihelion	6 Jun 2017	16.2	5.900 AU	5.296 AU	12h37m	-33°57'	122.3°	8.4°	97°
Today	9 Mar 2026	27.1	19.704 AU	19.963 AU	19h20m	+47°47'	73.5°	2.8°	297°

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)                : 1.0042430
    q (Perihelion distance)         : 5.9000290
    i (Inclination)                 : 70.66650
    Ω (Longitude of ascending node) : 220.75520
    ω (Argument of perihelion)      : 334.14860
    L (Longitude of perihelion)     : 211.64201
    B (Latitude of perihelion)      : -24.29591
    T (Time of perihelion passage)  : 2457911.32190

    Epoch                           : 2026 Mar 08
    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
2026-03-08 00:00 UT   19 20 05.6   +47 44 15    19.962   19.699   73.2    2.8   298   27.1 
2026-03-09 00:00 UT   19 20 17.4   +47 46 56    19.962   19.704   73.5    2.8   297   27.1 
2026-03-09 03:23 UT   19 20 19.1   +47 47 19    19.963   19.704   73.5    2.8   297   27.1 
2026-03-10 00:00 UT   19 20 29.1   +47 49 38    19.963   19.708   73.7    2.8   296   27.1 
2026-03-11 00:00 UT   19 20 40.5   +47 52 21    19.964   19.713   73.9    2.8   295   27.1 
2026-03-12 00:00 UT   19 20 51.7   +47 55 06    19.965   19.717   74.2    2.8   294   27.1 
2026-03-13 00:00 UT   19 21 02.6   +47 57 52    19.965   19.722   74.4    2.8   293   27.1 
2026-03-14 00:00 UT   19 21 13.2   +48 00 38    19.966   19.727   74.7    2.8   292   27.1 
2026-03-15 00:00 UT   19 21 23.6   +48 03 26    19.966   19.731   74.9    2.8   291   27.1 
2026-03-16 00:00 UT   19 21 33.7   +48 06 15    19.966   19.736   75.2    2.8   290   27.1 
2026-03-17 00:00 UT   19 21 43.6   +48 09 05    19.967   19.740   75.4    2.8   289   27.1 
2026-03-18 00:00 UT   19 21 53.2   +48 11 56    19.967   19.745   75.7    2.8   288   27.1 
2026-03-19 00:00 UT   19 22 02.6   +48 14 47    19.967   19.750   76.0    2.8   288   27.1 

    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.