C/2026 C1 (Tsuchinshan)
ephemeris	date	magn	radius	delta	ra	dec	elong	phase	PA
Today	29 Mar 2026	18.9	9.640 AU	8.657 AU	12h32m	+07°01'	169.7°	1.1°	184°
Perihelion	7 Nov 2028	5.0	1.152 AU	0.999 AU	19h08m	-82°45'	70.8°	54.3°	113°
Nearest approach	11 Nov 2028	5.0	1.155 AU	0.989 AU	20h40m	-74°46'	71.4°	54.4°	92°

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. (4.4 + 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/2026 C1 (Tsuchinshan) are:

    e (Eccentricity)                : 0.9998970
    q (Perihelion distance)         : 1.1524730
    i (Inclination)                 : 99.60010
    Ω (Longitude of ascending node) : 3.61820
    ω (Argument of perihelion)      : 310.72000
    L (Longitude of perihelion)     : 14.58349
    B (Latitude of perihelion)      : -48.35641
    T (Time of perihelion passage)  : 2462082.51720

    Epoch                           : 2026 Mar 28
    Reference                       : MPEC 2026-FC3

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

Ephemerides

Date       Time       RA (2000)    DEC (2000)    delta   radius  elong  phase   PA    magn
2026-03-28 00:00 UT   12 33 26.0   +06 59 05     8.665    9.649  170.1    1.0   191   18.9 
2026-03-29 00:00 UT   12 32 58.3   +07 00 57     8.658    9.642  169.8    1.1   185   18.9 
2026-03-29 03:52 UT   12 32 53.9   +07 01 14     8.657    9.640  169.7    1.1   184   18.9 
2026-03-30 00:00 UT   12 32 30.6   +07 02 46     8.651    9.634  169.4    1.1   180   18.9 
2026-03-31 00:00 UT   12 32 02.9   +07 04 35     8.645    9.627  168.9    1.1   174   18.9 
2026-04-01 00:00 UT   12 31 35.1   +07 06 22     8.639    9.620  168.4    1.2   169   18.9 
2026-04-02 00:00 UT   12 31 07.3   +07 08 08     8.634    9.612  167.7    1.3   165   18.9 
2026-04-03 00:00 UT   12 30 39.5   +07 09 53     8.628    9.605  167.1    1.3   161   18.9 
2026-04-04 00:00 UT   12 30 11.7   +07 11 36     8.623    9.598  166.3    1.4   158   18.9 
2026-04-05 00:00 UT   12 29 43.9   +07 13 18     8.619    9.590  165.5    1.5   154   18.9 
2026-04-06 00:00 UT   12 29 16.1   +07 14 58     8.615    9.583  164.7    1.6   152   18.9 
2026-04-07 00:00 UT   12 28 48.3   +07 16 36     8.611    9.575  163.8    1.7   149   18.9 
2026-04-08 00:00 UT   12 28 20.6   +07 18 13     8.607    9.568  162.9    1.8   147   18.9 

    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.