P/2021 N1 (ZTF)
ephemeris	date	magn	radius	delta	ra	dec	elong	phase	PA
Nearest approach	29 Jun 2026	14.6	1.049 AU	0.165 AU	00h33m	-17°35'	96.8°	74.2°	248°
Perihelion	28 Jul 2026	15.6	0.966 AU	0.303 AU	03h08m	+31°26'	72.1°	90.5°	258°
Today	12 Sep 2026	17.7	1.159 AU	0.563 AU	04h57m	+46°09'	90.7°	60.3°	263°

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 18.4 + 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 P/2021 N1 (ZTF) are:

    e (Eccentricity)                : 0.6757640
    q (Perihelion distance)         : 0.9663170
    i (Inclination)                 : 11.48530
    Ω (Longitude of ascending node) : 301.11370
    ω (Argument of perihelion)      : 21.21910
    L (Longitude of perihelion)     : 321.94469
    B (Latitude of perihelion)      : 4.13274
    T (Time of perihelion passage)  : 2461249.98630
    P (Orbital period in years)     : 5.15

    Epoch                           : 2026 Sep 11
    Reference                       : MPEC 2026-RA1

    Classification(s):              : Ecliptic; Jupiter family
    Tisserand (Jupiter)             : 2.839

Ephemerides

Date       Time       RA (2000)    DEC (2000)    delta   radius  elong  phase   PA    magn
2026-09-11 00:00 UT   04 56 19.2   +46 00 08     0.559    1.151   89.9   61.0   263   17.7 
2026-09-12 00:00 UT   04 57 29.4   +46 08 03     0.563    1.158   90.6   60.4   263   17.7 
2026-09-12 03:18 UT   04 57 38.8   +46 09 08     0.563    1.159   90.7   60.3   263   17.7 
2026-09-13 00:00 UT   04 58 35.5   +46 15 45     0.566    1.166   91.3   59.7   263   17.8 
2026-09-14 00:00 UT   04 59 37.5   +46 23 14     0.570    1.173   92.0   59.0   263   17.8 
2026-09-15 00:00 UT   05 00 35.1   +46 30 31     0.573    1.181   92.7   58.3   262   17.9 
2026-09-16 00:00 UT   05 01 28.5   +46 37 36     0.576    1.188   93.4   57.6   262   17.9 
2026-09-17 00:00 UT   05 02 17.6   +46 44 28     0.580    1.196   94.1   57.0   262   17.9 
2026-09-18 00:00 UT   05 03 02.3   +46 51 09     0.583    1.204   94.9   56.3   262   18.0 
2026-09-19 00:00 UT   05 03 42.5   +46 57 39     0.586    1.212   95.6   55.6   261   18.0 
2026-09-20 00:00 UT   05 04 18.2   +47 03 57     0.589    1.220   96.4   54.9   261   18.1 
2026-09-21 00:00 UT   05 04 49.4   +47 10 03     0.592    1.228   97.2   54.2   261   18.1 
2026-09-22 00:00 UT   05 05 16.0   +47 15 58     0.594    1.236   98.0   53.5   260   18.1 

    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.