C/2021 E3 (ZTF)
ephemeris	date	magn	radius	delta	ra	dec	elong	phase	PA
Nearest approach	31 May 2022	9.7	1.783 AU	1.224 AU	00h48m	-78°45'	105.2°	33.3°	233°
Perihelion	10 Jun 2022	9.7	1.778 AU	1.264 AU	06h07m	-78°44'	102.0°	33.9°	167°
Today	13 Oct 2026	27.7	13.407 AU	13.304 AU	07h14m	+28°04'	93.8°	4.3°	277°

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 5.5 + 5 log[∆] + 14.7 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/2021 E3 (ZTF) are:

    e (Eccentricity)                : 0.9992560
    q (Perihelion distance)         : 1.7783180
    i (Inclination)                 : 112.52850
    Ω (Longitude of ascending node) : 104.48460
    ω (Argument of perihelion)      : 228.77140
    L (Longitude of perihelion)     : 80.86868
    B (Latitude of perihelion)      : -44.00281
    T (Time of perihelion passage)  : 2459740.59430
    P (Orbital period in years)     : 116857.00

    Epoch                           : 2026 Oct 13
    Reference                       : MPC194173

    Classification(s):              : Nearly isotropic; Returning (a < 10000 AU); External (P > 200 years)

Ephemerides

Date       Time       RA (2000)    DEC (2000)    delta   radius  elong  phase   PA    magn
2026-10-12 00:00 UT   07 14 24.8   +28 02 10    13.325   13.395   91.9    4.3   277   27.7 
2026-10-13 00:00 UT   07 14 22.6   +28 03 15    13.314   13.401   92.9    4.3   277   27.7 
2026-10-13 21:47 UT   07 14 20.3   +28 04 15    13.304   13.407   93.8    4.3   277   27.7 
2026-10-14 00:00 UT   07 14 20.1   +28 04 21    13.303   13.407   93.9    4.3   277   27.7 
2026-10-15 00:00 UT   07 14 17.2   +28 05 27    13.292   13.414   94.9    4.2   277   27.8 
2026-10-16 00:00 UT   07 14 14.0   +28 06 34    13.281   13.420   95.9    4.2   277   27.8 
2026-10-17 00:00 UT   07 14 10.4   +28 07 42    13.270   13.426   96.9    4.2   277   27.8 
2026-10-18 00:00 UT   07 14 06.5   +28 08 51    13.259   13.432   97.9    4.2   276   27.8 
2026-10-19 00:00 UT   07 14 02.2   +28 09 60    13.248   13.438   98.9    4.2   276   27.8 
2026-10-20 00:00 UT   07 13 57.6   +28 11 09    13.237   13.444   99.9    4.2   276   27.8 
2026-10-21 00:00 UT   07 13 52.6   +28 12 20    13.227   13.451  100.9    4.2   276   27.8 
2026-10-22 00:00 UT   07 13 47.3   +28 13 31    13.216   13.457  101.9    4.2   276   27.8 
2026-10-23 00:00 UT   07 13 41.6   +28 14 42    13.205   13.463  102.9    4.1   276   27.8 

    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.