C/2013 US10 (Catalina)
ephemeris date magn radius delta ra dec elong phase PA
Perihelion12 Nov 20156.30.813 AU1.749 AU 14h15m-18°32'12.6°15.4°268°
Nearest approach15 Jan 20166.21.403 AU0.745 AU 13h42m+55°22'107.8°41.9°282°
Today4 Feb 202623.225.721 AU25.791 AU 02h00m+33°05'84.8°2.2°67°
C/2013 US10 (Catalina)- 2026-02-04
astro.vanbuitenen.nl


 
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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. This lightcurve is being recalculated every 6 hours based on the available COBS/MPC observations (currently 5.8 + 5 log[∆] + 7.4 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 US10 (Catalina) are:

    e (Eccentricity)                : 1.0001630
    q (Perihelion distance)         : 0.8125860
    i (Inclination)                 : 148.89550
    Ω (Longitude of ascending node) : 186.20490
    ω (Argument of perihelion)      : 340.21770
    L (Longitude of perihelion)     : 203.32173
    B (Latitude of perihelion)      : -10.06947
    T (Time of perihelion passage)  : 2457339.05560

    Epoch                           : 2026 Feb 03
    Reference                       : MPC xxxxx

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

Ephemerides

Date       Time       RA (2000)    DEC (2000)    delta   radius  elong  phase   PA    magn
2026-02-03 00:00 UT   02 00 53.8   +33 06 40    25.758   25.713   86.3    2.2    67   23.2 
2026-02-04 00:00 UT   02 00 55.6   +33 05 56    25.779   25.718   85.3    2.2    67   23.2 
2026-02-04 14:02 UT   02 00 56.7   +33 05 30    25.791   25.721   84.8    2.2    67   23.2 
2026-02-05 00:00 UT   02 00 57.6   +33 05 12    25.800   25.723   84.4    2.2    67   23.2 
2026-02-06 00:00 UT   02 00 59.7   +33 04 30    25.821   25.727   83.4    2.2    66   23.2 
2026-02-07 00:00 UT   02 01 02.0   +33 03 49    25.842   25.732   82.5    2.2    66   23.2 
2026-02-08 00:00 UT   02 01 04.5   +33 03 09    25.863   25.737   81.5    2.2    66   23.2 
2026-02-09 00:00 UT   02 01 07.1   +33 02 30    25.884   25.742   80.6    2.2    65   23.2 
2026-02-10 00:00 UT   02 01 10.0   +33 01 52    25.905   25.746   79.6    2.2    65   23.2 
2026-02-11 00:00 UT   02 01 13.0   +33 01 15    25.926   25.751   78.7    2.2    65   23.2 
2026-02-12 00:00 UT   02 01 16.1   +33 00 40    25.947   25.756   77.7    2.1    64   23.2 
2026-02-13 00:00 UT   02 01 19.4   +33 00 05    25.967   25.760   76.8    2.1    64   23.2 
2026-02-14 00:00 UT   02 01 22.9   +32 59 31    25.988   25.765   75.8    2.1    64   23.3 



    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.