C/2024 C4 (ATLAS)
ephemeris	date	magn	radius	delta	ra	dec	elong	phase	PA
Perihelion	30 Jan 2024	16.0	1.471 AU	1.688 AU	16h34m	-54°34'	60.2°	35.5°	259°
Nearest approach	12 Apr 2024	15.6	1.785 AU	0.945 AU	16h30m	-00°12'	132.7°	24.4°	258°
Today	15 Jan 2025	23.1	4.421 AU	4.767 AU	17h52m	+36°30'	63.7°	11.5°	330°

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/2024 C4 (ATLAS) are:

            e (Eccentricity)                : 0.9824270
            q (Perihelion distance)         : 1.4708610
            i (Inclination)                 : 79.28520
            Ω (Longitude of ascending node) : 220.68090
            ω (Argument of perihelion)      : 321.50800
            L (Longitude of perihelion)     : 212.27091
            B (Latitude of perihelion)      : -37.70192
            T (Time of perihelion passage)  : 2460339.69220
            P (Orbital period in years)     : 765.75

            Epoch                           : 2025 Jan 13
            Reference                       : MPEC 2024-Q20

            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 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 (14.50 + 5 log[∆] + 10.00 log[r]), whereas the red curve is being recalculated every 6 hours based on the available COBS/MPC observations (currently 13.20 + 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
2025-01-15 00:00 UT   17 52 18.5   +36 29 05     4.766    4.419   63.7   11.5   330   23.0 
2025-01-15 04:57 UT   17 52 33.1   +36 30 58     4.767    4.421   63.7   11.5   330   23.1 
2025-01-16 00:00 UT   17 53 29.0   +36 38 15     4.771    4.428   63.9   11.5   329   23.1 
2025-01-17 00:00 UT   17 54 39.2   +36 47 32     4.775    4.437   64.2   11.5   329   23.1 
2025-01-18 00:00 UT   17 55 49.0   +36 56 54     4.780    4.447   64.5   11.5   328   23.1 
2025-01-19 00:00 UT   17 56 58.4   +37 06 23     4.785    4.456   64.8   11.5   327   23.1 
2025-01-20 00:00 UT   17 58 07.4   +37 15 59     4.789    4.465   65.1   11.5   326   23.1 
2025-01-21 00:00 UT   17 59 16.1   +37 25 40     4.794    4.474   65.4   11.5   325   23.1 
2025-01-22 00:00 UT   18 00 24.4   +37 35 28     4.799    4.484   65.7   11.5   325   23.1 
2025-01-23 00:00 UT   18 01 32.2   +37 45 22     4.803    4.493   65.9   11.5   324   23.1 
2025-01-24 00:00 UT   18 02 39.7   +37 55 22     4.808    4.502   66.2   11.5   323   23.1 
2025-01-25 00:00 UT   18 03 46.7   +38 05 28     4.812    4.511   66.5   11.5   322   23.2 

    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.