199P/Shoemaker
ephemeris	date	magn	radius	delta	ra	dec	elong	phase	PA
Nearest approach	28 Jun 2023	16.2	2.923 AU	1.908 AU	18h14m	-24°47'	176.7°	1.1°	63°
Perihelion	6 Aug 2023	16.4	2.910 AU	2.108 AU	17h53m	-30°12'	134.5°	14.4°	84°
Today	1 Sep 2026	22.4	6.664 AU	6.578 AU	04h36m	+07°33'	90.5°	8.7°	262°

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 10.1 + 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 199P/Shoemaker are:

    e (Eccentricity)                : 0.5040850
    q (Perihelion distance)         : 2.9099370
    i (Inclination)                 : 24.94250
    Ω (Longitude of ascending node) : 92.33650
    ω (Argument of perihelion)      : 191.69550
    L (Longitude of perihelion)     : 102.96727
    B (Latitude of perihelion)      : -4.90390
    T (Time of perihelion passage)  : 2460163.27160
    P (Orbital period in years)     : 14.21

    Epoch                           : 2026 Sep 01
    Reference                       : MPC191611

    Classification(s):              : Ecliptic; Jupiter family
    Tisserand (Jupiter)             : 2.550

Ephemerides

Date       Time       RA (2000)    DEC (2000)    delta   radius  elong  phase   PA    magn
2026-08-31 00:00 UT   04 35 51.8   +07 35 24     6.602    6.659   88.8    8.7   261   22.4 
2026-09-01 00:00 UT   04 36 01.7   +07 34 40     6.589    6.662   89.7    8.7   261   22.4 
2026-09-01 21:31 UT   04 36 10.1   +07 33 59     6.578    6.664   90.5    8.7   262   22.4 
2026-09-02 00:00 UT   04 36 11.1   +07 33 54     6.577    6.665   90.6    8.7   262   22.4 
2026-09-03 00:00 UT   04 36 19.8   +07 33 06     6.564    6.668   91.5    8.7   262   22.4 
2026-09-04 00:00 UT   04 36 28.0   +07 32 17     6.551    6.671   92.4    8.7   262   22.4 
2026-09-05 00:00 UT   04 36 35.7   +07 31 27     6.538    6.674   93.4    8.7   262   22.4 
2026-09-06 00:00 UT   04 36 42.7   +07 30 35     6.526    6.677   94.3    8.7   263   22.4 
2026-09-07 00:00 UT   04 36 49.2   +07 29 42     6.513    6.680   95.2    8.6   263   22.4 
2026-09-08 00:00 UT   04 36 55.0   +07 28 47     6.500    6.683   96.1    8.6   263   22.4 
2026-09-09 00:00 UT   04 37 00.3   +07 27 51     6.488    6.686   97.0    8.6   263   22.4 
2026-09-10 00:00 UT   04 37 05.0   +07 26 54     6.475    6.689   97.9    8.6   264   22.4 
2026-09-11 00:00 UT   04 37 09.1   +07 25 55     6.462    6.692   98.9    8.5   264   22.4 

    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.