C/2021 A7 (NEOWISE)
ephemeris	date	magn	radius	delta	ra	dec	elong	phase	PA
Nearest approach	5 Apr 2021	15.2	2.313 AU	2.136 AU	06h29m	-30°36'	87.1°	25.6°	99°
Perihelion	15 Jul 2021	15.1	1.966 AU	2.813 AU	09h25m	+12°16'	27.3°	13.7°	113°
Today	14 Mar 2026	27.2	13.981 AU	14.580 AU	20h46m	+28°18'	51.3°	3.2°	300°

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 9.9 + 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/2021 A7 (NEOWISE) are:

    e (Eccentricity)                : 0.9990590
    q (Perihelion distance)         : 1.9663870
    i (Inclination)                 : 78.24810
    Ω (Longitude of ascending node) : 154.36630
    ω (Argument of perihelion)      : 356.02980
    L (Longitude of perihelion)     : 153.55643
    B (Latitude of perihelion)      : -3.88685
    T (Time of perihelion passage)  : 2459410.72560
    P (Orbital period in years)     : 95525.44

    Epoch                           : 2026 Mar 14
    Reference                       : MPEC 2026-E44

    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
2026-03-13 00:00 UT   20 45 46.8   +28 14 37    14.579   13.970   50.6    3.1   302   27.2 
2026-03-14 00:00 UT   20 46 01.2   +28 16 45    14.580   13.976   51.0    3.2   300   27.2 
2026-03-14 20:04 UT   20 46 13.1   +28 18 33    14.580   13.981   51.3    3.2   300   27.2 
2026-03-15 00:00 UT   20 46 15.4   +28 18 54    14.580   13.982   51.4    3.2   299   27.2 
2026-03-16 00:00 UT   20 46 29.4   +28 21 04    14.580   13.988   51.8    3.2   298   27.2 
2026-03-17 00:00 UT   20 46 43.2   +28 23 16    14.580   13.994   52.3    3.2   297   27.2 
2026-03-18 00:00 UT   20 46 56.8   +28 25 30    14.580   14.000   52.7    3.2   296   27.2 
2026-03-19 00:00 UT   20 47 10.2   +28 27 45    14.580   14.006   53.2    3.3   295   27.2 
2026-03-20 00:00 UT   20 47 23.3   +28 30 01    14.579   14.012   53.6    3.3   294   27.2 
2026-03-21 00:00 UT   20 47 36.2   +28 32 19    14.578   14.018   54.1    3.3   293   27.2 
2026-03-22 00:00 UT   20 47 48.9   +28 34 37    14.577   14.024   54.6    3.3   292   27.2 
2026-03-23 00:00 UT   20 48 01.3   +28 36 58    14.576   14.030   55.1    3.3   291   27.2 
2026-03-24 00:00 UT   20 48 13.5   +28 39 19    14.575   14.036   55.5    3.4   290   27.2 

    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.