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	1 Oct 2026	27.7	13.333 AU	13.436 AU	07h14m	+27°51'	81.9°	4.3°	278°

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)                : 0.9992660
    q (Perihelion distance)         : 1.7782910
    i (Inclination)                 : 112.52830
    Ω (Longitude of ascending node) : 104.48460
    ω (Argument of perihelion)      : 228.77180
    L (Longitude of perihelion)     : 80.86856
    B (Latitude of perihelion)      : -44.00323
    T (Time of perihelion passage)  : 2459740.61900
    P (Orbital period in years)     : 119250.49

    Epoch                           : 2026 Oct 01
    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
2026-09-30 00:00 UT   07 14 24.0   +27 50 02    13.456   13.321   80.1    4.2   278   27.7 
2026-10-01 00:00 UT   07 14 25.9   +27 50 59    13.446   13.327   81.0    4.3   278   27.7 
2026-10-01 21:42 UT   07 14 27.3   +27 51 51    13.436   13.333   81.9    4.3   278   27.7 
2026-10-02 00:00 UT   07 14 27.5   +27 51 56    13.435   13.333   82.0    4.3   278   27.7 
2026-10-03 00:00 UT   07 14 28.7   +27 52 55    13.424   13.339   83.0    4.3   278   27.7 
2026-10-04 00:00 UT   07 14 29.7   +27 53 53    13.413   13.346   84.0    4.3   278   27.7 
2026-10-05 00:00 UT   07 14 30.3   +27 54 53    13.402   13.352   85.0    4.3   278   27.7 
2026-10-06 00:00 UT   07 14 30.5   +27 55 53    13.391   13.358   85.9    4.3   278   27.7 
2026-10-07 00:00 UT   07 14 30.4   +27 56 54    13.380   13.364   86.9    4.3   278   27.7 
2026-10-08 00:00 UT   07 14 30.0   +27 57 56    13.369   13.370   87.9    4.3   278   27.7 
2026-10-09 00:00 UT   07 14 29.2   +27 58 58    13.358   13.377   88.9    4.3   277   27.7 
2026-10-10 00:00 UT   07 14 28.1   +28 00 01    13.347   13.383   89.9    4.3   277   27.7 
2026-10-11 00:00 UT   07 14 26.6   +28 01 05    13.336   13.389   90.9    4.3   277   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.