C/2020 A2 (Iwamoto)
ephemeris	date	magn	radius	delta	ra	dec	elong	phase	PA
Perihelion	6 Jan 2020	10.3	0.976 AU	1.627 AU	17h49m	+05°13'	33.7°	34.0°	326°
Nearest approach	20 Feb 2020	10.1	1.241 AU	0.913 AU	19h50m	+65°54'	81.3°	52.0°	324°
Today	24 Oct 2025	27.8	17.184 AU	16.698 AU	05h46m	-11°49'	117.7°	2.9°	290°

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 9.4 + 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 C/2020 A2 (Iwamoto) are:

    e (Eccentricity)                : 0.9989480
    q (Perihelion distance)         : 0.9760470
    i (Inclination)                 : 120.49660
    Ω (Longitude of ascending node) : 286.18050
    ω (Argument of perihelion)      : 68.01690
    L (Longitude of perihelion)     : 234.68116
    B (Latitude of perihelion)      : 53.03583
    T (Time of perihelion passage)  : 2458855.26300
    P (Orbital period in years)     : 28260.67

    Epoch                           : 2025 Oct 23
    Reference                       : MPEC 2022-YN2

    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
2025-10-23 00:00 UT   05 46 48.6   -11 46 49    16.705   17.177  116.8    3.0   289   27.8 
2025-10-24 00:00 UT   05 46 39.6   -11 48 47    16.699   17.183  117.6    2.9   290   27.8 
2025-10-24 04:19 UT   05 46 38.0   -11 49 08    16.698   17.184  117.7    2.9   290   27.8 
2025-10-25 00:00 UT   05 46 30.4   -11 50 43    16.693   17.188  118.3    2.9   291   27.8 
2025-10-26 00:00 UT   05 46 20.9   -11 52 38    16.688   17.194  119.1    2.9   292   27.8 
2025-10-27 00:00 UT   05 46 11.3   -11 54 32    16.682   17.200  119.9    2.9   292   27.8 
2025-10-28 00:00 UT   05 46 01.4   -11 56 25    16.677   17.205  120.6    2.8   293   27.8 
2025-10-29 00:00 UT   05 45 51.3   -11 58 17    16.672   17.211  121.4    2.8   294   27.8 
2025-10-30 00:00 UT   05 45 41.0   -12 00 08    16.667   17.217  122.2    2.8   295   27.8 
2025-10-31 00:00 UT   05 45 30.5   -12 01 57    16.662   17.222  122.9    2.8   296   27.8 
2025-11-01 00:00 UT   05 45 19.8   -12 03 45    16.657   17.228  123.7    2.7   297   27.8 
2025-11-02 00:00 UT   05 45 09.0   -12 05 31    16.653   17.234  124.4    2.7   297   27.8 
2025-11-03 00:00 UT   05 44 57.9   -12 07 16    16.649   17.239  125.1    2.7   298   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.