C/2017 T2 (PANSTARRS)
ephemeris	date	magn	radius	delta	ra	dec	elong	phase	PA
Nearest approach	28 Dec 2019	9.8	2.335 AU	1.524 AU	03h34m	+52°45'	136.1°	17.0°	115°
Perihelion	6 May 2020	8.6	1.602 AU	1.699 AU	07h02m	+75°28'	67.0°	35.4°	67°
Today	13 Dec 2025	22.4	16.266 AU	16.932 AU	19h22m	-64°50'	46.2°	2.5°	140°

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 5.7 + 5 log[∆] + 8.8 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 T2 (PANSTARRS) are:

    e (Eccentricity)                : 0.9990480
    q (Perihelion distance)         : 1.6020440
    i (Inclination)                 : 57.27160
    Ω (Longitude of ascending node) : 64.41460
    ω (Argument of perihelion)      : 92.77300
    L (Longitude of perihelion)     : -20.46612
    B (Latitude of perihelion)      : 57.16736
    T (Time of perihelion passage)  : 2458975.96960
    P (Orbital period in years)     : 69032.92

    Epoch                           : 2025 Dec 12
    Reference                       : MPEC 2024-A43

    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
2025-12-12 00:00 UT   19 22 06.7   -64 51 24    16.921   16.260   46.6    2.5   138   22.4 
2025-12-13 00:00 UT   19 22 39.2   -64 50 10    16.931   16.266   46.2    2.5   140   22.4 
2025-12-13 02:12 UT   19 22 42.2   -64 50 04    16.932   16.266   46.2    2.5   140   22.4 
2025-12-14 00:00 UT   19 23 11.9   -64 48 59    16.941   16.272   45.9    2.5   141   22.4 
2025-12-15 00:00 UT   19 23 44.8   -64 47 48    16.951   16.277   45.5    2.5   142   22.4 
2025-12-16 00:00 UT   19 24 17.8   -64 46 40    16.961   16.283   45.2    2.5   143   22.4 
2025-12-17 00:00 UT   19 24 51.0   -64 45 33    16.970   16.289   44.9    2.4   144   22.4 
2025-12-18 00:00 UT   19 25 24.4   -64 44 28    16.979   16.295   44.6    2.4   145   22.4 
2025-12-19 00:00 UT   19 25 58.0   -64 43 25    16.989   16.300   44.4    2.4   147   22.4 
2025-12-20 00:00 UT   19 26 31.6   -64 42 23    16.997   16.306   44.1    2.4   148   22.4 
2025-12-21 00:00 UT   19 27 05.5   -64 41 23    17.006   16.312   43.9    2.4   149   22.5 
2025-12-22 00:00 UT   19 27 39.4   -64 40 25    17.015   16.317   43.6    2.4   150   22.5 
2025-12-23 00:00 UT   19 28 13.5   -64 39 29    17.023   16.323   43.4    2.4   152   22.5 

    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.