C/2017 F2 (PANSTARRS)
ephemeris	date	magn	radius	delta	ra	dec	elong	phase	PA
Perihelion	27 Nov 2017	20.2	6.899 AU	7.349 AU	13h19m	+20°41'	59.4°	7.1°	312°
Nearest approach	31 Mar 2018	19.8	6.947 AU	6.042 AU	13h23m	+20°29'	153.0°	3.7°	206°
Today	19 Jul 2026	26.6	19.152 AU	18.419 AU	17h59m	-61°20'	135.1°	2.1°	39°

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)                : 1.0022820
    q (Perihelion distance)         : 6.8994960
    i (Inclination)                 : 42.52870
    Ω (Longitude of ascending node) : 38.63520
    ω (Argument of perihelion)      : 134.77700
    L (Longitude of perihelion)     : 2.03401
    B (Latitude of perihelion)      : 28.67444
    T (Time of perihelion passage)  : 2458084.78220

    Epoch                           : 2026 Jul 18
    Reference                       : MPC194151

    Classification(s):              : Nearly isotropic; New (a > 10000 AU)

Ephemerides

Date       Time       RA (2000)    DEC (2000)    delta   radius  elong  phase   PA    magn
2026-07-18 00:00 UT   17 59 54.2   -61 20 56    18.407   19.147  135.6    2.1    37   26.6 
2026-07-19 00:00 UT   17 59 35.3   -61 20 20    18.417   19.152  135.1    2.1    39   26.6 
2026-07-19 03:38 UT   17 59 32.5   -61 20 14    18.419   19.152  135.1    2.1    39   26.6 
2026-07-20 00:00 UT   17 59 16.7   -61 19 41    18.428   19.156  134.6    2.2    40   26.7 
2026-07-21 00:00 UT   17 58 58.3   -61 19 01    18.439   19.161  134.1    2.2    41   26.7 
2026-07-22 00:00 UT   17 58 40.2   -61 18 19    18.449   19.165  133.6    2.2    42   26.7 
2026-07-23 00:00 UT   17 58 22.3   -61 17 35    18.460   19.169  133.1    2.2    44   26.7 
2026-07-24 00:00 UT   17 58 04.6   -61 16 50    18.472   19.174  132.6    2.2    45   26.7 
2026-07-25 00:00 UT   17 57 47.3   -61 16 03    18.483   19.178  132.0    2.3    46   26.7 
2026-07-26 00:00 UT   17 57 30.2   -61 15 13    18.495   19.183  131.5    2.3    47   26.7 
2026-07-27 00:00 UT   17 57 13.4   -61 14 23    18.507   19.187  130.9    2.3    48   26.7 
2026-07-28 00:00 UT   17 56 56.9   -61 13 30    18.519   19.192  130.3    2.3    49   26.7 
2026-07-29 00:00 UT   17 56 40.6   -61 12 36    18.531   19.196  129.7    2.3    50   26.7 

    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.