C/2021 K3 (Catalina)
ephemeris	date	magn	radius	delta	ra	dec	elong	phase	PA
Perihelion	3 Feb 2022	21.1	5.228 AU	6.156 AU	19h55m	-22°02'	18.0°	3.3°	255°
Nearest approach	28 Jun 2022	20.5	5.340 AU	4.360 AU	19h01m	-38°55'	162.8°	3.2°	333°
Today	2 Jul 2025	25.1	10.122 AU	9.993 AU	11h24m	-47°33'	94.4°	5.7°	120°

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/2021 K3 (Catalina) are:

            e (Eccentricity)                : 1.0041880
            q (Perihelion distance)         : 5.2275930
            i (Inclination)                 : 134.78050
            Ω (Longitude of ascending node) : 114.60830
            ω (Argument of perihelion)      : 182.01280
            L (Longitude of perihelion)     : 113.19020
            B (Latitude of perihelion)      : -1.42856
            T (Time of perihelion passage)  : 2459614.14170

            Epoch                           : 2025 Jun 30
            Reference                       : MPEC 2022-L66

            Classification(s):              : Nearly isotropic; New (a > 10000 AU)
        

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. (10.00 + 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
2025-07-02 00:00 UT   11 24 02.8   -47 33 40     9.991   10.122   94.5    5.7   120   25.1 
2025-07-02 01:51 UT   11 24 03.0   -47 33 17     9.993   10.122   94.4    5.7   120   25.1 
2025-07-03 00:00 UT   11 24 06.2   -47 28 46    10.009   10.127   93.8    5.7   120   25.1 
2025-07-04 00:00 UT   11 24 10.1   -47 23 57    10.027   10.132   93.1    5.8   121   25.1 
2025-07-05 00:00 UT   11 24 14.4   -47 19 11    10.044   10.138   92.4    5.8   122   25.1 
2025-07-06 00:00 UT   11 24 19.2   -47 14 30    10.062   10.143   91.7    5.8   123   25.1 
2025-07-07 00:00 UT   11 24 24.5   -47 09 52    10.080   10.148   91.0    5.7   123   25.1 
2025-07-08 00:00 UT   11 24 30.2   -47 05 19    10.097   10.154   90.3    5.7   124   25.1 
2025-07-09 00:00 UT   11 24 36.3   -47 00 50    10.115   10.159   89.6    5.7   125   25.1 
2025-07-10 00:00 UT   11 24 42.9   -46 56 25    10.133   10.164   88.9    5.7   125   25.1 
2025-07-11 00:00 UT   11 24 49.9   -46 52 05    10.150   10.170   88.2    5.7   126   25.1 
2025-07-12 00:00 UT   11 24 57.3   -46 47 48    10.168   10.175   87.5    5.7   126   25.1 

    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.