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	14 Jul 2025	31.4	14.728 AU	14.056 AU	16h01m	-18°51'	129.8°	3.0°	103°

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
2025-07-14 00:00 UT   16 01 52.6   -18 51 43    14.042   14.725  130.7    3.0   103   31.4 
2025-07-14 20:36 UT   16 01 45.2   -18 51 29    14.056   14.728  129.8    3.0   103   31.4 
2025-07-15 00:00 UT   16 01 44.0   -18 51 27    14.058   14.728  129.7    3.0   103   31.4 
2025-07-16 00:00 UT   16 01 35.7   -18 51 11    14.074   14.731  128.7    3.1   103   31.4 
2025-07-17 00:00 UT   16 01 27.7   -18 50 56    14.091   14.735  127.7    3.1   103   31.4 
2025-07-18 00:00 UT   16 01 19.9   -18 50 41    14.107   14.738  126.7    3.2   103   31.4 
2025-07-19 00:00 UT   16 01 12.3   -18 50 28    14.124   14.741  125.8    3.2   103   31.4 
2025-07-20 00:00 UT   16 01 05.0   -18 50 15    14.141   14.744  124.8    3.2   103   31.4 
2025-07-21 00:00 UT   16 00 58.0   -18 50 03    14.158   14.747  123.8    3.3   103   31.4 
2025-07-22 00:00 UT   16 00 51.2   -18 49 51    14.175   14.750  122.8    3.3   103   31.4 
2025-07-23 00:00 UT   16 00 44.7   -18 49 41    14.192   14.754  121.8    3.4   102   31.4 
2025-07-24 00:00 UT   16 00 38.4   -18 49 31    14.210   14.757  120.9    3.4   102   31.5 

    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.