C/2017 F2 (PANSTARRS)
ephemeris	date	magn	radius	delta	ra	dec	elong	phase	PA
Perihelion	27 Nov 2017	20.2	6.899 AU	7.351 AU	13h19m	+20°41'	59.2°	7.1°	312°
Nearest approach	31 Mar 2018	19.8	6.947 AU	6.042 AU	13h23m	+20°28'	153.0°	3.7°	206°
Today	17 May 2026	26.6	18.871 AU	18.216 AU	18h20m	-60°50'	129.1°	2.4°	306°

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. The light curve is based on the absolute magnitude and slope parameter as calculated from an MPEC, or the latest values provided by the minor planet center. (7.5 + 5 log[∆] + 10.0 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 F2 (PANSTARRS) are:

    e (Eccentricity)                : 1.0021720
    q (Perihelion distance)         : 6.8989990
    i (Inclination)                 : 42.53210
    Ω (Longitude of ascending node) : 38.64420
    ω (Argument of perihelion)      : 134.76320
    L (Longitude of perihelion)     : 2.03129
    B (Latitude of perihelion)      : 28.68396
    T (Time of perihelion passage)  : 2458084.57840

    Epoch                           : 2026 May 16
    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
2026-05-16 00:00 UT   18 20 59.2   -60 48 36    18.220   18.866  128.5    2.4   305   26.6 
2026-05-17 00:00 UT   18 20 43.7   -60 50 08    18.216   18.871  129.1    2.4   306   26.6 
2026-05-17 02:13 UT   18 20 42.3   -60 50 16    18.216   18.871  129.1    2.4   306   26.6 
2026-05-18 00:00 UT   18 20 28.0   -60 51 38    18.213   18.875  129.7    2.4   307   26.6 
2026-05-19 00:00 UT   18 20 11.9   -60 53 07    18.209   18.879  130.3    2.3   308   26.6 
2026-05-20 00:00 UT   18 19 55.6   -60 54 35    18.206   18.884  130.9    2.3   309   26.6 
2026-05-21 00:00 UT   18 19 38.9   -60 56 00    18.203   18.888  131.4    2.3   310   26.6 
2026-05-22 00:00 UT   18 19 22.0   -60 57 24    18.200   18.893  132.0    2.3   311   26.6 
2026-05-23 00:00 UT   18 19 04.8   -60 58 46    18.197   18.897  132.6    2.3   313   26.6 
2026-05-24 00:00 UT   18 18 47.3   -61 00 07    18.195   18.902  133.1    2.2   314   26.6 
2026-05-25 00:00 UT   18 18 29.5   -61 01 25    18.193   18.906  133.6    2.2   315   26.6 
2026-05-26 00:00 UT   18 18 11.5   -61 02 42    18.191   18.911  134.2    2.2   316   26.6 
2026-05-27 00:00 UT   18 17 53.3   -61 03 57    18.189   18.915  134.7    2.2   318   26.6 

    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.