29P/Schwassmann-Wachmann
ephemeris	date	magn	radius	delta	ra	dec	elong	phase	PA
Nearest approach	9 Sep 2018	11.7	5.807 AU	4.806 AU	23h04m	+01°07'	173.4°	1.1°	163°
Perihelion	18 Apr 2019	12.4	5.798 AU	6.717 AU	00h15m	+08°32'	22.0°	3.7°	262°
Today	27 Aug 2026	13.0	6.318 AU	7.226 AU	11h41m	-04°42'	24.1°	3.7°	127°

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 .7 + 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 29P/Schwassmann-Wachmann are:

    e (Eccentricity)                : 0.0429030
    q (Perihelion distance)         : 5.7980690
    i (Inclination)                 : 9.35500
    Ω (Longitude of ascending node) : 312.40060
    ω (Argument of perihelion)      : 51.34000
    L (Longitude of perihelion)     : 3.36585
    B (Latitude of perihelion)      : 7.29227
    T (Time of perihelion passage)  : 2458592.15210
    P (Orbital period in years)     : 14.91

    Epoch                           : 2026 Aug 27
    Reference                       : MPEC 2026-P55

    Classification(s):              : Ecliptic; Jupiter family
    Tisserand (Jupiter)             : 2.986

Ephemerides

Date       Time       RA (2000)    DEC (2000)    delta   radius  elong  phase   PA    magn
2026-08-26 00:00 UT   11 40 03.9   -04 34 25     7.215    6.318   25.5    4.0   127   13.0 
2026-08-27 00:00 UT   11 40 42.9   -04 38 39     7.221    6.318   24.8    3.8   127   13.0 
2026-08-27 21:05 UT   11 41 17.2   -04 42 23     7.226    6.318   24.1    3.7   127   13.0 
2026-08-28 00:00 UT   11 41 21.9   -04 42 54     7.227    6.318   24.0    3.7   128   13.0 
2026-08-29 00:00 UT   11 42 01.1   -04 47 11     7.233    6.318   23.2    3.6   128   13.0 
2026-08-30 00:00 UT   11 42 40.4   -04 51 29     7.239    6.318   22.5    3.5   129   13.0 
2026-08-31 00:00 UT   11 43 19.8   -04 55 49     7.244    6.318   21.7    3.4   129   13.0 
2026-09-01 00:00 UT   11 43 59.3   -05 00 10     7.250    6.318   21.0    3.3   130   13.0 
2026-09-02 00:00 UT   11 44 38.9   -05 04 33     7.255    6.318   20.2    3.2   131   13.0 
2026-09-03 00:00 UT   11 45 18.6   -05 08 56     7.260    6.318   19.5    3.1   131   13.0 
2026-09-04 00:00 UT   11 45 58.4   -05 13 21     7.264    6.318   18.8    2.9   132   13.0 
2026-09-05 00:00 UT   11 46 38.3   -05 17 48     7.269    6.318   18.0    2.8   133   13.0 
2026-09-06 00:00 UT   11 47 18.3   -05 22 16     7.273    6.318   17.3    2.7   134   13.0 

    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.