C/2021 A2 (NEOWISE)
ephemeris	date	magn	radius	delta	ra	dec	elong	phase	PA
Perihelion	21 Jan 2021	11.4	1.418 AU	0.631 AU	09h08m	-37°43'	121.2°	36.4°	346°
Nearest approach	2 Feb 2021	11.1	1.428 AU	0.509 AU	07h29m	-10°35'	143.9°	24.0°	41°
Today	17 Feb 2026	60.9	15.182 AU	15.801 AU	20h48m	+34°31'	49.8°	2.8°	336°

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 6.2 + 5 log[∆] + 41.2 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 A2 (NEOWISE) are:

    e (Eccentricity)                : 0.9938570
    q (Perihelion distance)         : 1.4177930
    i (Inclination)                 : 107.06540
    Ω (Longitude of ascending node) : 125.04400
    ω (Argument of perihelion)      : 338.81800
    L (Longitude of perihelion)     : 131.53185
    B (Latitude of perihelion)      : -20.20758
    T (Time of perihelion passage)  : 2459236.27620
    P (Orbital period in years)     : 3506.30

    Epoch                           : 2025 Nov 12
    Reference                       : MPEC 2025-A40

    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
2026-02-16 00:00 UT   20 47 51.4   +34 30 19    15.793   15.174   49.8    2.8   338   60.9 
2026-02-17 00:00 UT   20 48 08.0   +34 31 26    15.799   15.180   49.8    2.8   337   60.9 
2026-02-17 06:32 UT   20 48 12.6   +34 31 45    15.801   15.182   49.8    2.8   336   60.9 
2026-02-18 00:00 UT   20 48 24.6   +34 32 36    15.805   15.186   49.8    2.8   335   60.9 
2026-02-19 00:00 UT   20 48 41.1   +34 33 49    15.811   15.192   49.8    2.8   334   60.9 
2026-02-20 00:00 UT   20 48 57.4   +34 35 04    15.817   15.198   49.8    2.8   333   60.9 
2026-02-21 00:00 UT   20 49 13.6   +34 36 21    15.822   15.204   49.8    2.8   332   60.9 
2026-02-22 00:00 UT   20 49 29.7   +34 37 41    15.828   15.209   49.9    2.8   330   60.9 
2026-02-23 00:00 UT   20 49 45.7   +34 39 04    15.833   15.215   49.9    2.9   329   60.9 
2026-02-24 00:00 UT   20 50 01.6   +34 40 29    15.838   15.221   50.0    2.9   328   60.9 
2026-02-25 00:00 UT   20 50 17.3   +34 41 56    15.843   15.227   50.1    2.9   327   60.9 
2026-02-26 00:00 UT   20 50 32.9   +34 43 25    15.847   15.233   50.2    2.9   326   60.9 
2026-02-27 00:00 UT   20 50 48.3   +34 44 57    15.852   15.239   50.3    2.9   324   60.9 

    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.