C/2023 H1 (PANSTARRS)
ephemeris	date	magn	radius	delta	ra	dec	elong	phase	PA
Nearest approach	2 Jun 2024	18.1	4.678 AU	3.736 AU	15h28m	-41°02'	155.5°	5.2°	45°
Perihelion	28 Nov 2024	18.6	4.448 AU	5.367 AU	17h32m	-31°07'	19.2°	4.2°	116°
Today	2 Jul 2025	18.2	4.776 AU	3.812 AU	20h10m	-18°02'	159.2°	4.3°	252°

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/2023 H1 (PANSTARRS) are:

            e (Eccentricity)                : 0.9941300
            q (Perihelion distance)         : 4.4475710
            i (Inclination)                 : 21.78280
            Ω (Longitude of ascending node) : 292.64670
            ω (Argument of perihelion)      : 333.75080
            L (Longitude of perihelion)     : 268.04283
            B (Latitude of perihelion)      : -9.44634
            T (Time of perihelion passage)  : 2460643.13130
            P (Orbital period in years)     : 20855.82

            Epoch                           : 2025 Jun 30
            Reference                       : MPEC 2025-MC0

            Classification(s):              : Nearly isotropic; Returning (a < 10000 AU); External (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. (8.50 + 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
2025-07-02 00:00 UT   20 10 40.9   -18 03 08     3.813    4.776  159.1    4.4   253   18.2 
2025-07-02 02:19 UT   20 10 38.4   -18 02 54     3.812    4.776  159.2    4.3   252   18.2 
2025-07-03 00:00 UT   20 10 14.8   -18 00 41     3.811    4.779  160.1    4.2   252   18.2 
2025-07-04 00:00 UT   20 09 48.3   -17 58 16     3.809    4.782  161.1    3.9   252   18.2 
2025-07-05 00:00 UT   20 09 21.5   -17 55 51     3.807    4.785  162.2    3.7   251   18.2 
2025-07-06 00:00 UT   20 08 54.4   -17 53 28     3.806    4.788  163.2    3.5   250   18.2 
2025-07-07 00:00 UT   20 08 27.0   -17 51 05     3.804    4.791  164.2    3.3   250   18.2 
2025-07-08 00:00 UT   20 07 59.4   -17 48 44     3.804    4.794  165.3    3.1   249   18.2 
2025-07-09 00:00 UT   20 07 31.4   -17 46 24     3.803    4.797  166.3    2.9   248   18.2 
2025-07-10 00:00 UT   20 07 03.3   -17 44 05     3.803    4.800  167.3    2.7   247   18.2 
2025-07-11 00:00 UT   20 06 34.9   -17 41 47     3.803    4.803  168.3    2.5   246   18.2 
2025-07-12 00:00 UT   20 06 06.4   -17 39 30     3.803    4.806  169.3    2.2   244   18.2 

    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.