C/2018 Y1 (Iwamoto)
ephemeris	date	magn	radius	delta	ra	dec	elong	phase	PA
Perihelion	3 Feb 2019	7.3	1.293 AU	0.430 AU	12h20m	-04°35'	127.4°	37.3°	295°
Nearest approach	11 Feb 2019	6.6	1.298 AU	0.313 AU	09h59m	+19°47'	172.3°	5.9°	225°
Today	26 Apr 2025	33.3	17.528 AU	18.325 AU	23h45m	+09°13'	36.5°	2.0°	260°

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/2018 Y1 (Iwamoto) are:

            e (Eccentricity)                : 0.9897690
            q (Perihelion distance)         : 1.2927030
            i (Inclination)                 : 160.47930
            Ω (Longitude of ascending node) : 147.34250
            ω (Argument of perihelion)      : 357.86520
            L (Longitude of perihelion)     : 149.35470
            B (Latitude of perihelion)      : -0.71319
            T (Time of perihelion passage)  : 2458517.97400
            P (Orbital period in years)     : 1420.27

            Epoch                           : 2025 Apr 24
            Reference                       : MPEC 2024-A43

            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 (11.50 + 5 log[∆] + 10.00 log[r]), whereas the red curve is being recalculated every 6 hours based on the available COBS/MPC observations (currently 7.38 + 5 log[∆] + 15.73 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
2025-04-26 00:00 UT   23 45 20.9   +09 13 18    18.326   17.528   36.5    2.0   260   33.3 
2025-04-26 00:32 UT   23 45 21.1   +09 13 19    18.325   17.528   36.5    2.0   260   33.3 
2025-04-27 00:00 UT   23 45 29.1   +09 14 27    18.321   17.533   37.4    2.0   259   33.3 
2025-04-28 00:00 UT   23 45 37.1   +09 15 36    18.317   17.538   38.3    2.0   259   33.3 
2025-04-29 00:00 UT   23 45 45.1   +09 16 44    18.312   17.544   39.2    2.1   259   33.3 
2025-04-30 00:00 UT   23 45 52.9   +09 17 53    18.307   17.549   40.1    2.1   258   33.3 
2025-05-01 00:00 UT   23 46 00.5   +09 19 00    18.302   17.555   41.0    2.2   258   33.3 
2025-05-02 00:00 UT   23 46 08.1   +09 20 08    18.296   17.560   41.9    2.2   257   33.3 
2025-05-03 00:00 UT   23 46 15.4   +09 21 14    18.291   17.565   42.8    2.2   257   33.3 
2025-05-04 00:00 UT   23 46 22.7   +09 22 21    18.285   17.571   43.7    2.3   257   33.3 
2025-05-05 00:00 UT   23 46 29.8   +09 23 26    18.279   17.576   44.6    2.3   256   33.3 
2025-05-06 00:00 UT   23 46 36.7   +09 24 32    18.273   17.581   45.5    2.3   256   33.3 

    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.