C/2016 R2 (PANSTARRS)
ephemeris	date	magn	radius	delta	ra	dec	elong	phase	PA
Nearest approach	22 Dec 2017	11.6	2.985 AU	2.065 AU	04h33m	+10°21'	154.9°	8.0°	56°
Perihelion	11 May 2018	11.9	2.594 AU	3.290 AU	05h34m	+44°52'	39.7°	14.4°	59°
Today	14 Dec 2025	26.3	19.371 AU	20.339 AU	17h01m	-15°05'	10.0°	0.5°	325°

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 4.3 + 5 log[∆] + 12.0 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/2016 R2 (PANSTARRS) are:

    e (Eccentricity)                : 0.9954710
    q (Perihelion distance)         : 2.5943700
    i (Inclination)                 : 58.38390
    Ω (Longitude of ascending node) : 80.47080
    ω (Argument of perihelion)      : 33.17310
    L (Longitude of perihelion)     : 99.38698
    B (Latitude of perihelion)      : 27.77231
    T (Time of perihelion passage)  : 2458250.42190
    P (Orbital period in years)     : 13710.22

    Epoch                           : 2025 Dec 13
    Reference                       : MPEC 2021-N06

    Classification(s):              : Nearly isotropic; Returning (a < 10000 AU); External (P > 200 years)

Ephemerides

Date       Time       RA (2000)    DEC (2000)    delta   radius  elong  phase   PA    magn
2025-12-13 00:00 UT   17 01 28.2   -15 04 38    20.334   19.364    9.2    0.5   332   26.3 
2025-12-14 00:00 UT   17 01 40.9   -15 05 11    20.338   19.369    9.7    0.5   327   26.3 
2025-12-14 09:08 UT   17 01 45.7   -15 05 24    20.339   19.371   10.0    0.5   325   26.3 
2025-12-15 00:00 UT   17 01 53.6   -15 05 44    20.341   19.374   10.4    0.5   323   26.3 
2025-12-16 00:00 UT   17 02 06.3   -15 06 17    20.343   19.379   11.0    0.6   319   26.3 
2025-12-17 00:00 UT   17 02 19.0   -15 06 49    20.346   19.384   11.7    0.6   316   26.3 
2025-12-18 00:00 UT   17 02 31.6   -15 07 20    20.348   19.389   12.5    0.6   313   26.3 
2025-12-19 00:00 UT   17 02 44.2   -15 07 51    20.350   19.394   13.3    0.7   310   26.3 
2025-12-20 00:00 UT   17 02 56.7   -15 08 22    20.352   19.399   14.1    0.7   308   26.3 
2025-12-21 00:00 UT   17 03 09.2   -15 08 52    20.353   19.404   14.9    0.7   306   26.3 
2025-12-22 00:00 UT   17 03 21.7   -15 09 21    20.354   19.410   15.7    0.8   304   26.3 
2025-12-23 00:00 UT   17 03 34.1   -15 09 50    20.355   19.415   16.6    0.8   302   26.3 
2025-12-24 00:00 UT   17 03 46.5   -15 10 18    20.355   19.420   17.4    0.9   301   26.3 

    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.