C/2018 A4 (PANSTARRS)
ephemeris	date	magn	radius	delta	ra	dec	elong	phase	PA
Nearest approach	14 Nov 2017	20.3	2.996 AU	2.065 AU	01h53m	+07°20'	156.2°	7.7°	60°
Perihelion	20 May 2018	20.4	2.387 AU	3.271 AU	05h31m	+23°06'	24.5°	10.1°	87°
Today	22 Jun 2025	31.4	14.656 AU	13.748 AU	16h05m	-19°00'	152.4°	1.8°	104°

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/2018 A4 (PANSTARRS) are:

            e (Eccentricity)                : 0.8041630
            q (Perihelion distance)         : 2.3868650
            i (Inclination)                 : 3.15180
            Ω (Longitude of ascending node) : 97.56170
            ω (Argument of perihelion)      : 355.95760
            L (Longitude of perihelion)     : 93.52539
            B (Latitude of perihelion)      : -0.22207
            T (Time of perihelion passage)  : 2458258.73910
            P (Orbital period in years)     : 42.55

            Epoch                           : 2023 Sep 24
            Reference                       : MPEC 2023-J29

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

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 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. (14.00 + 5 log[∆] + 10.00 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
2025-06-22 00:00 UT   16 05 54.9   -19 00 33    13.745   14.655  152.6    1.8   104   31.4 
2025-06-22 05:14 UT   16 05 52.1   -19 00 27    13.748   14.656  152.4    1.8   104   31.4 
2025-06-23 00:00 UT   16 05 41.9   -19 00 03    13.756   14.658  151.6    1.9   104   31.4 
2025-06-24 00:00 UT   16 05 29.1   -18 59 33    13.767   14.662  150.6    2.0   104   31.4 
2025-06-25 00:00 UT   16 05 16.4   -18 59 04    13.779   14.665  149.6    2.0   104   31.4 
2025-06-26 00:00 UT   16 05 03.9   -18 58 35    13.791   14.668  148.6    2.1   104   31.4 
2025-06-27 00:00 UT   16 04 51.5   -18 58 07    13.803   14.671  147.6    2.1   104   31.4 
2025-06-28 00:00 UT   16 04 39.4   -18 57 40    13.815   14.674  146.6    2.2   104   31.4 
2025-06-29 00:00 UT   16 04 27.4   -18 57 13    13.827   14.677  145.6    2.2   104   31.4 
2025-06-30 00:00 UT   16 04 15.6   -18 56 46    13.840   14.681  144.6    2.3   104   31.4 
2025-07-01 00:00 UT   16 04 04.0   -18 56 21    13.853   14.684  143.6    2.4   104   31.4 
2025-07-02 00:00 UT   16 03 52.6   -18 55 55    13.866   14.687  142.6    2.4   103   31.4 

    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.