C/2015 O1 (PANSTARRS)
ephemeris	date	magn	radius	delta	ra	dec	elong	phase	PA
Perihelion	20 Feb 2018	13.1	3.719 AU	3.542 AU	16h32m	+35°50'	92.5°	15.4°	282°
Nearest approach	5 Apr 2018	13.0	3.740 AU	3.224 AU	15h23m	+52°25'	113.7°	14.2°	220°
Today	27 May 2025	23.7	18.115 AU	18.902 AU	06h17m	-02°59'	38.0°	2.0°	131°

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.)

The orbital elements of C/2015 O1 (PANSTARRS) are:

            e (Eccentricity)                : 1.0013020
            q (Perihelion distance)         : 3.7191240
            i (Inclination)                 : 127.16050
            Ω (Longitude of ascending node) : 299.81790
            ω (Argument of perihelion)      : 89.50740
            L (Longitude of perihelion)     : 210.63336
            B (Latitude of perihelion)      : 52.83671
            T (Time of perihelion passage)  : 2458169.67540

            Epoch                           : 2023 Apr 14
            Reference                       : MPEC 2021-P47

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

The light curve chart below shows the estimated development of the comet's magnitude. Blue and black dots are visual and photometric CCD observations respectively from COBS or the MPC. The gray curve is based on the absolute magnitude and slope parameter as calculated from the original MPEC, or the latest values provided by the MPC (6.50 + 5 log[∆] + 10.00 log[r]), whereas the red curve is being recalculated every 6 hours based on the available COBS/MPC observations (currently 4.66 + 5 log[∆] + 10.07 log[r]).

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.
A more printer-friendly version of the same chart can be found further down this page as well.

The following chart shows the current location of the comet in a smaller, upside-down telescopic field of view.

A printable version of the short-term path of the comet in a field of view that is optimized for (~10x50) binoculars and finderscopes.

Ephemerides:

Date       Time       RA (2000)    DEC (2000)    delta   radius  elong  phase   PA    magn
2025-05-27 00:00 UT   06 16 55.7   -02 59 38    18.893   18.111   38.5    2.0   130   23.7 
2025-05-27 17:16 UT   06 17 02.7   -02 59 28    18.902   18.115   38.0    2.0   131   23.7 
2025-05-28 00:00 UT   06 17 05.4   -02 59 24    18.905   18.116   37.8    2.0   132   23.7 
2025-05-29 00:00 UT   06 17 15.1   -02 59 12    18.918   18.121   37.2    1.9   133   23.7 
2025-05-30 00:00 UT   06 17 24.9   -02 59 01    18.930   18.126   36.6    1.9   134   23.7 
2025-05-31 00:00 UT   06 17 34.8   -02 58 51    18.942   18.132   36.0    1.9   135   23.7 
2025-06-01 00:00 UT   06 17 44.7   -02 58 42    18.953   18.137   35.4    1.9   136   23.7 
2025-06-02 00:00 UT   06 17 54.7   -02 58 35    18.965   18.142   34.8    1.8   137   23.7 
2025-06-03 00:00 UT   06 18 04.8   -02 58 29    18.976   18.147   34.2    1.8   139   23.7 
2025-06-04 00:00 UT   06 18 14.9   -02 58 24    18.987   18.152   33.7    1.8   140   23.7 
2025-06-05 00:00 UT   06 18 25.2   -02 58 21    18.998   18.157   33.1    1.8   141   23.7 
2025-06-06 00:00 UT   06 18 35.4   -02 58 19    19.008   18.162   32.6    1.7   143   23.7 

    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.