C/2013 UQ4 (Catalina)
ephemeris	date	magn	radius	delta	ra	dec	elong	phase	PA
Perihelion	4 Jul 2014	11.8	1.099 AU	0.387 AU	23h16m	+40°30'	91.7°	67.6°	237°
Nearest approach	9 Jul 2014	11.5	1.102 AU	0.332 AU	20h37m	+59°49'	96.0°	66.6°	199°
Today	26 Apr 2025	34.5	25.084 AU	24.925 AU	09h02m	+15°28'	97.9°	2.3°	106°

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/2013 UQ4 (Catalina) are:

            e (Eccentricity)                : 0.9812680
            q (Perihelion distance)         : 1.0987550
            i (Inclination)                 : 145.21210
            Ω (Longitude of ascending node) : 317.80900
            ω (Argument of perihelion)      : 23.74980
            L (Longitude of perihelion)     : 297.94097
            B (Latitude of perihelion)      : 13.28420
            T (Time of perihelion passage)  : 2456842.78700
            P (Orbital period in years)     : 449.24

            Epoch                           : 2020 Sep 26
            Reference                       : MPC102951

            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. (13.50 + 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
2025-04-26 00:00 UT   09 02 55.3   +15 28 08    24.924   25.084   98.0    2.3   106   34.5 
2025-04-26 01:03 UT   09 02 55.3   +15 28 08    24.925   25.084   97.9    2.3   106   34.5 
2025-04-27 00:00 UT   09 02 53.6   +15 28 14    24.945   25.088   97.0    2.3   106   34.5 
2025-04-28 00:00 UT   09 02 52.0   +15 28 19    24.966   25.092   96.0    2.3   106   34.5 
2025-04-29 00:00 UT   09 02 50.6   +15 28 24    24.987   25.096   95.0    2.3   106   34.5 
2025-04-30 00:00 UT   09 02 49.3   +15 28 27    25.008   25.101   94.1    2.3   106   34.5 
2025-05-01 00:00 UT   09 02 48.2   +15 28 31    25.030   25.105   93.1    2.3   106   34.5 
2025-05-02 00:00 UT   09 02 47.2   +15 28 33    25.051   25.109   92.1    2.3   106   34.5 
2025-05-03 00:00 UT   09 02 46.4   +15 28 35    25.072   25.113   91.1    2.3   107   34.5 
2025-05-04 00:00 UT   09 02 45.8   +15 28 36    25.093   25.117   90.2    2.3   107   34.5 
2025-05-05 00:00 UT   09 02 45.3   +15 28 37    25.115   25.121   89.2    2.3   107   34.5 
2025-05-06 00:00 UT   09 02 45.0   +15 28 36    25.136   25.126   88.2    2.3   107   34.5 

    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.