C/2016 R2 (PANSTARRS)
ephemeris	date	magn	radius	delta	ra	dec	elong	phase	PA
Nearest approach	22 Dec 2017	11.6	2.988 AU	2.067 AU	04h33m	+10°23'	155.0°	8.0°	56°
Perihelion	12 May 2018	11.9	2.597 AU	3.294 AU	05h34m	+44°52'	39.6°	14.4°	59°
Today	30 May 2026	26.4	20.214 AU	19.217 AU	17h04m	-15°10'	169.3°	0.5°	231°

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)                : 0.9955740
    q (Perihelion distance)         : 2.5970480
    i (Inclination)                 : 58.38360
    Ω (Longitude of ascending node) : 80.49170
    ω (Argument of perihelion)      : 33.17680
    L (Longitude of perihelion)     : 99.41050
    B (Latitude of perihelion)      : 27.77519
    T (Time of perihelion passage)  : 2458250.57360
    P (Orbital period in years)     : 14213.56

    Epoch                           : 2026 May 29
    Reference                       : MPC194149

    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
2026-05-29 00:00 UT   17 04 23.3   -15 10 29    19.213   20.206  168.1    0.6   236   26.4 
2026-05-30 00:00 UT   17 04 11.5   -15 10 26    19.215   20.211  168.9    0.6   233   26.4 
2026-05-30 13:32 UT   17 04 04.9   -15 10 25    19.217   20.214  169.3    0.5   231   26.4 
2026-05-31 00:00 UT   17 03 59.8   -15 10 25    19.218   20.216  169.6    0.5   229   26.4 
2026-06-01 00:00 UT   17 03 48.0   -15 10 23    19.221   20.221  170.2    0.5   225   26.4 
2026-06-02 00:00 UT   17 03 36.2   -15 10 22    19.224   20.226  170.8    0.5   220   26.4 
2026-06-03 00:00 UT   17 03 24.4   -15 10 21    19.227   20.231  171.4    0.4   214   26.4 
2026-06-04 00:00 UT   17 03 12.5   -15 10 20    19.231   20.236  171.8    0.4   208   26.4 
2026-06-05 00:00 UT   17 03 00.7   -15 10 20    19.235   20.241  172.1    0.4   201   26.4 
2026-06-06 00:00 UT   17 02 48.8   -15 10 20    19.240   20.246  172.3    0.4   194   26.4 
2026-06-07 00:00 UT   17 02 37.0   -15 10 20    19.244   20.251  172.4    0.4   187   26.4 
2026-06-08 00:00 UT   17 02 25.1   -15 10 21    19.249   20.256  172.4    0.4   179   26.4 
2026-06-09 00:00 UT   17 02 13.3   -15 10 22    19.254   20.261  172.2    0.4   172   26.4 

    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.