P/2010 H3 (SOHO)
ephemeris	date	magn	radius	delta	ra	dec	elong	phase	PA
Perihelion	29 Feb 2024	13.4	0.046 AU	0.968 AU	22h53m	-06°37'	2.3°	117.9°	56°
Nearest approach	1 Mar 2024	15.3	0.123 AU	0.919 AU	22h27m	-07°14'	6.0°	122.8°	271°
Today	3 Apr 2026	27.8	5.990 AU	5.961 AU	19h18m	-30°43'	86.8°	9.6°	262°

This comet is a sunskirter. Although it may become very bright at perihelion, this will only be for a very short period very close to the sun.

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. (20.0 + 5 log[∆] + 5.0 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 P/2010 H3 (SOHO) are:

    e (Eccentricity)                : 0.9874040
    q (Perihelion distance)         : 0.0458200
    i (Inclination)                 : 23.14890
    Ω (Longitude of ascending node) : 77.07800
    ω (Argument of perihelion)      : 25.95790
    L (Longitude of perihelion)     : 101.19260
    B (Latitude of perihelion)      : 9.90841
    T (Time of perihelion passage)  : 2460369.69920
    P (Orbital period in years)     : 6.94

    Epoch                           : 2026 Mar 16
    Reference                       : MPEC 2026-E44

    Classification(s):              : Nearly isotropic; Returning (a < 10000 AU); Halley type (P < 200 years); Sunskirter; Marsden

Ephemerides

Date       Time       RA (2000)    DEC (2000)    delta   radius  elong  phase   PA    magn
2026-04-02 00:00 UT   19 18 18.3   -30 40 49     5.989    5.986   85.0    9.6   262   27.8 
2026-04-03 00:00 UT   19 18 23.8   -30 42 12     5.974    5.988   86.0    9.6   262   27.8 
2026-04-03 21:03 UT   19 18 28.0   -30 43 27     5.961    5.990   86.8    9.6   262   27.8 
2026-04-04 00:00 UT   19 18 28.5   -30 43 37     5.960    5.990   86.9    9.6   262   27.8 
2026-04-05 00:00 UT   19 18 32.6   -30 45 05     5.945    5.992   87.9    9.6   262   27.8 
2026-04-06 00:00 UT   19 18 35.8   -30 46 34     5.930    5.995   88.9    9.6   262   27.8 
2026-04-07 00:00 UT   19 18 38.3   -30 48 04     5.916    5.997   89.8    9.6   262   27.7 
2026-04-08 00:00 UT   19 18 40.0   -30 49 37     5.901    5.999   90.8    9.6   262   27.7 
2026-04-09 00:00 UT   19 18 40.9   -30 51 12     5.886    6.002   91.8    9.6   262   27.7 
2026-04-10 00:00 UT   19 18 41.0   -30 52 48     5.872    6.004   92.8    9.6   263   27.7 
2026-04-11 00:00 UT   19 18 40.3   -30 54 26     5.857    6.006   93.7    9.6   263   27.7 
2026-04-12 00:00 UT   19 18 38.9   -30 56 06     5.842    6.008   94.7    9.6   263   27.7 
2026-04-13 00:00 UT   19 18 36.6   -30 57 48     5.828    6.011   95.7    9.6   263   27.7 

    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.