C/2020 A2 (Iwamoto)
ephemeris	date	magn	radius	delta	ra	dec	elong	phase	PA
Perihelion	6 Jan 2020	10.3	0.976 AU	1.626 AU	17h49m	+05°13'	33.7°	34.0°	326°
Nearest approach	20 Feb 2020	10.1	1.240 AU	0.913 AU	19h50m	+65°52'	81.3°	52.0°	324°
Today	18 Sep 2025	27.8	16.983 AU	16.968 AU	05h49m	-10°34'	89.1°	3.4°	268°

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.)

The orbital elements of C/2020 A2 (Iwamoto) are:

            e (Eccentricity)                : 0.9989610
            q (Perihelion distance)         : 0.9757280
            i (Inclination)                 : 120.49810
            Ω (Longitude of ascending node) : 286.18200
            ω (Argument of perihelion)      : 68.01460
            L (Longitude of perihelion)     : 234.68465
            B (Latitude of perihelion)      : 53.03343
            T (Time of perihelion passage)  : 2458855.38700
            P (Orbital period in years)     : 28778.61

            Epoch                           : 2025 Sep 17
            Reference                       : MPEC 2022-YN2

            Classification(s):              : Nearly isotropic; Returning (a < 10000 AU); External (P > 200 years)
        

The light curve chart below shows the estimated development of the comet's magnitude. Blue and black dots are visual and photometric CCD observations respectively from COBS or the MPC. The gray curve is based on the absolute magnitude and slope parameter as calculated from the original MPEC, or the latest values provided by the MPC (13.50 + 5 log[∆] + 10.00 log[r]), whereas the red curve is being recalculated every 6 hours based on the available COBS/MPC observations (currently 9.37 + 5 log[∆] + 10.00 log[r]).

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.
A more printer-friendly version of the same chart can be found further down this page as well.

The following chart shows the current location of the comet in a smaller, upside-down telescopic field of view.

A printable version of the short-term path of the comet in a field of view that is optimized for (~10x50) binoculars and finderscopes.

Ephemerides:

Date       Time       RA (2000)    DEC (2000)    delta   radius  elong  phase   PA    magn
2025-09-18 00:00 UT   05 49 35.4   -10 32 10    16.975   16.978   88.4    3.4   268   27.8 
2025-09-18 20:59 UT   05 49 34.9   -10 34 04    16.968   16.983   89.1    3.4   268   27.8 
2025-09-19 00:00 UT   05 49 34.8   -10 34 21    16.967   16.983   89.2    3.4   268   27.8 
2025-09-20 00:00 UT   05 49 33.9   -10 36 32    16.958   16.989   90.0    3.4   269   27.8 
2025-09-21 00:00 UT   05 49 32.8   -10 38 43    16.950   16.995   90.8    3.4   269   27.8 
2025-09-22 00:00 UT   05 49 31.4   -10 40 54    16.941   17.001   91.7    3.4   270   27.8 
2025-09-23 00:00 UT   05 49 29.8   -10 43 05    16.933   17.006   92.5    3.4   270   27.8 
2025-09-24 00:00 UT   05 49 28.0   -10 45 17    16.924   17.012   93.3    3.4   271   27.8 
2025-09-25 00:00 UT   05 49 25.9   -10 47 28    16.916   17.018   94.1    3.4   272   27.8 
2025-09-26 00:00 UT   05 49 23.5   -10 49 40    16.907   17.023   94.9    3.4   272   27.8 
2025-09-27 00:00 UT   05 49 21.0   -10 51 51    16.899   17.029   95.7    3.4   273   27.8 
2025-09-28 00:00 UT   05 49 18.1   -10 54 03    16.890   17.035   96.6    3.4   273   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.