C/2013 UQ4 (Catalina)
ephemeris	date	magn	radius	delta	ra	dec	elong	phase	PA
Perihelion	8 Jul 2014	11.4	1.076 AU	0.335 AU	23h11m	+48°00'	90.9°	70.9°	234°
Nearest approach	11 Jul 2014	11.3	1.077 AU	0.306 AU	20h53m	+62°59'	93.1°	70.4°	201°
Today	1 Jul 2026	35.0	26.856 AU	27.683 AU	09h03m	+14°56'	34.9°	1.2°	109°

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.)

Light curve

The light curve chart below shows the estimated development of the comet's magnitude. Blue and black dots are visual and photometric CCD observations from COBS. 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. (13.5 + 5 log[∆] + 10.0 log[r]). An additional green curve is displayed when an increase in apparent brightness is expected due to forward scattering of sunlight, which occurs when a dust-rich comet is located between the Earth and the Sun. (See Marcus 2007)

Charts

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.

Orbital elements

The orbital elements of C/2013 UQ4 (Catalina) are:

    e (Eccentricity)                : 0.9817550
    q (Perihelion distance)         : 1.0756980
    i (Inclination)                 : 144.79810
    Ω (Longitude of ascending node) : 317.79270
    ω (Argument of perihelion)      : 23.50180
    L (Longitude of perihelion)     : 298.23120
    B (Latitude of perihelion)      : 13.28996
    T (Time of perihelion passage)  : 2456846.66640
    P (Orbital period in years)     : 452.71

    Epoch                           : 2026 May 29
    Reference                       : MPC194135

    Classification(s):              : Nearly isotropic; Returning (a < 10000 AU); External (P > 200 years)

Ephemerides

Date       Time       RA (2000)    DEC (2000)    delta   radius  elong  phase   PA    magn
2026-06-30 00:00 UT   09 03 26.3   +14 56 57    27.665   26.851   36.1    1.3   109   35.0 
2026-07-01 00:00 UT   09 03 32.7   +14 56 28    27.679   26.855   35.2    1.2   109   35.0 
2026-07-01 07:43 UT   09 03 34.8   +14 56 18    27.683   26.856   34.9    1.2   109   35.0 
2026-07-02 00:00 UT   09 03 39.2   +14 55 58    27.692   26.859   34.2    1.2   109   35.0 
2026-07-03 00:00 UT   09 03 45.8   +14 55 27    27.706   26.863   33.3    1.2   109   35.0 
2026-07-04 00:00 UT   09 03 52.4   +14 54 57    27.719   26.867   32.4    1.2   109   35.0 
2026-07-05 00:00 UT   09 03 59.1   +14 54 26    27.732   26.871   31.5    1.1   110   35.0 
2026-07-06 00:00 UT   09 04 05.8   +14 53 54    27.745   26.875   30.5    1.1   110   35.0 
2026-07-07 00:00 UT   09 04 12.7   +14 53 23    27.757   26.879   29.6    1.1   110   35.0 
2026-07-08 00:00 UT   09 04 19.5   +14 52 51    27.769   26.883   28.7    1.0   110   35.0 
2026-07-09 00:00 UT   09 04 26.5   +14 52 18    27.781   26.887   27.8    1.0   110   35.0 
2026-07-10 00:00 UT   09 04 33.5   +14 51 46    27.793   26.891   26.8    1.0   110   35.0 
2026-07-11 00:00 UT   09 04 40.5   +14 51 13    27.805   26.895   25.9    0.9   110   35.0 

    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.