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 Aug 2025	31.6	14.849 AU	14.770 AU	15h59m	-18°50'	92.5°	3.9°	102°

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
2025-08-22 00:00 UT   15 59 34.4   -18 50 36    14.763   14.848   92.8    3.9   102   31.6 
2025-08-22 07:50 UT   15 59 35.0   -18 50 40    14.770   14.849   92.5    3.9   102   31.6 
2025-08-23 00:00 UT   15 59 36.4   -18 50 50    14.783   14.851   91.9    3.9   102   31.6 
2025-08-24 00:00 UT   15 59 38.5   -18 51 05    14.803   14.854   90.9    3.9   102   31.6 
2025-08-25 00:00 UT   15 59 41.0   -18 51 21    14.823   14.857   90.0    3.9   102   31.6 
2025-08-26 00:00 UT   15 59 43.8   -18 51 37    14.843   14.860   89.0    3.9   101   31.6 
2025-08-27 00:00 UT   15 59 46.8   -18 51 54    14.863   14.864   88.1    3.9   101   31.6 
2025-08-28 00:00 UT   15 59 50.1   -18 52 12    14.883   14.867   87.1    3.9   101   31.6 
2025-08-29 00:00 UT   15 59 53.6   -18 52 31    14.903   14.870   86.2    3.9   101   31.6 
2025-08-30 00:00 UT   15 59 57.4   -18 52 51    14.923   14.873   85.2    3.9   101   31.6 
2025-08-31 00:00 UT   16 00 01.5   -18 53 11    14.943   14.876   84.3    3.9   101   31.6 
2025-09-01 00:00 UT   16 00 05.9   -18 53 32    14.963   14.879   83.3    3.9   101   31.6 

    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.