A/2023 R3
ephemeris	date	magn	radius	delta	ra	dec	elong	phase	PA
Nearest approach	6 Dec 2023	19.8	1.369 AU	0.494 AU	01h25m	+46°26'	132.6°	32.0°	102°
Perihelion	18 Dec 2023	19.9	1.359 AU	0.501 AU	01h56m	+49°05'	129.4°	34.0°	99°
Today	11 May 2025	27.2	5.953 AU	5.149 AU	12h27m	-10°30'	139.4°	6.3°	105°

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 A/2023 R3 are:

            e (Eccentricity)                : 0.9980980
            q (Perihelion distance)         : 1.3585530
            i (Inclination)                 : 12.08140
            Ω (Longitude of ascending node) : 347.34280
            ω (Argument of perihelion)      : 86.93790
            L (Longitude of perihelion)     : 74.21148
            B (Latitude of perihelion)      : 12.06389
            T (Time of perihelion passage)  : 2460296.68300
            P (Orbital period in years)     : 19089.70

            Epoch                           : 2025 May 10
            Reference                       : MPEC 2023-UR6

            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 indicates the expected brightness if this object is a comet (20.00 + 5 log[∆] + 5.00 log[r]), whereas the red curve indicates the expected lightcurve for an asteroid (H=19.30; G=.15).

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
2025-05-11 00:00 UT   12 27 27.5   -10 31 39     5.143    5.950  139.8    6.3   105   27.2 
2025-05-11 07:50 UT   12 27 21.5   -10 30 54     5.149    5.953  139.4    6.3   105   27.2 
2025-05-12 00:00 UT   12 27 09.3   -10 29 20     5.162    5.959  138.7    6.4   105   27.2 
2025-05-13 00:00 UT   12 26 51.7   -10 27 04     5.181    5.968  137.7    6.5   106   27.2 
2025-05-14 00:00 UT   12 26 34.8   -10 24 51     5.201    5.976  136.7    6.7   106   27.3 
2025-05-15 00:00 UT   12 26 18.4   -10 22 42     5.220    5.985  135.6    6.8   106   27.3 
2025-05-16 00:00 UT   12 26 02.8   -10 20 35     5.240    5.994  134.6    6.9   107   27.3 
2025-05-17 00:00 UT   12 25 47.8   -10 18 31     5.260    6.002  133.6    7.0   107   27.3 
2025-05-18 00:00 UT   12 25 33.4   -10 16 31     5.280    6.011  132.6    7.1   107   27.3 
2025-05-19 00:00 UT   12 25 19.6   -10 14 34     5.300    6.020  131.6    7.2   107   27.3 
2025-05-20 00:00 UT   12 25 06.5   -10 12 40     5.321    6.029  130.6    7.3   108   27.4 
2025-05-21 00:00 UT   12 24 54.1   -10 10 50     5.342    6.037  129.6    7.4   108   27.4 

    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.