C/2021 K3 (Catalina)
ephemeris	date	magn	radius	delta	ra	dec	elong	phase	PA
Perihelion	3 Feb 2022	21.1	5.227 AU	6.156 AU	19h55m	-22°01'	17.9°	3.3°	255°
Nearest approach	28 Jun 2022	20.5	5.339 AU	4.360 AU	19h01m	-38°55'	162.8°	3.2°	333°
Today	22 Aug 2025	25.3	10.396 AU	10.861 AU	11h34m	-44°56'	60.2°	4.8°	155°

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)                : 1.0041270
            q (Perihelion distance)         : 5.2269590
            i (Inclination)                 : 134.78050
            Ω (Longitude of ascending node) : 114.61130
            ω (Argument of perihelion)      : 182.00610
            L (Longitude of perihelion)     : 113.19793
            B (Latitude of perihelion)      : -1.42381
            T (Time of perihelion passage)  : 2459614.09300

            Epoch                           : 2025 Aug 21
            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
2025-08-22 00:00 UT   11 34 30.4   -44 56 29    10.855   10.394   60.4    4.9   154   25.3 
2025-08-22 08:29 UT   11 34 37.0   -44 56 04    10.861   10.396   60.2    4.8   155   25.3 
2025-08-23 00:00 UT   11 34 49.0   -44 55 20    10.870   10.399   59.8    4.8   155   25.4 
2025-08-24 00:00 UT   11 35 07.6   -44 54 14    10.885   10.404   59.2    4.8   156   25.4 
2025-08-25 00:00 UT   11 35 26.4   -44 53 13    10.899   10.410   58.7    4.8   157   25.4 
2025-08-26 00:00 UT   11 35 45.3   -44 52 17    10.914   10.415   58.1    4.7   157   25.4 
2025-08-27 00:00 UT   11 36 04.3   -44 51 24    10.928   10.420   57.5    4.7   158   25.4 
2025-08-28 00:00 UT   11 36 23.4   -44 50 36    10.942   10.426   56.9    4.7   159   25.4 
2025-08-29 00:00 UT   11 36 42.6   -44 49 52    10.956   10.431   56.4    4.6   160   25.4 
2025-08-30 00:00 UT   11 37 01.9   -44 49 13    10.970   10.436   55.8    4.6   161   25.4 
2025-08-31 00:00 UT   11 37 21.3   -44 48 37    10.983   10.442   55.3    4.6   162   25.4 
2025-09-01 00:00 UT   11 37 40.7   -44 48 06    10.997   10.447   54.7    4.5   163   25.4 

    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.