A/2025 Y1
ephemeris	date	magn	radius	delta	ra	dec	elong	phase	PA
Today	20 Jan 2026	14.6	6.491 AU	6.211 AU	13h12m	-01°22'	102.3°	8.5°	291°
Nearest approach	22 Jun 2027	10.4	2.877 AU	1.960 AU	16h34m	-00°06'	148.8°	10.6°	140°
Perihelion	15 Oct 2027	11.3	2.609 AU	2.783 AU	18h00m	-12°12'	69.6°	21.0°	86°

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. The displayed light curve is calculated under the assumption that the object remains inactive. (H=6.00; G=.15).

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 A/2025 Y1 are:

    e (Eccentricity)                : 0.9983700
    q (Perihelion distance)         : 2.6087690
    i (Inclination)                 : 14.55200
    Ω (Longitude of ascending node) : 166.54650
    ω (Argument of perihelion)      : 124.24020
    L (Longitude of perihelion)     : 111.66076
    B (Latitude of perihelion)      : 11.98830
    T (Time of perihelion passage)  : 2461693.52460
    P (Orbital period in years)     : 64028.31

    Epoch                           : 2026 Jan 19
    Reference                       : MPEC 2026-A90

    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
2026-01-19 00:00 UT   13 12 35.4   -01 23 44     6.236    6.499  101.2    8.5   291   14.6 
2026-01-20 00:00 UT   13 12 45.0   -01 22 53     6.213    6.492  102.2    8.5   291   14.6 
2026-01-20 02:17 UT   13 12 45.9   -01 22 48     6.211    6.491  102.3    8.5   291   14.6 
2026-01-21 00:00 UT   13 12 54.1   -01 21 57     6.189    6.485  103.2    8.5   291   14.6 
2026-01-22 00:00 UT   13 13 02.6   -01 20 58     6.166    6.477  104.2    8.5   291   14.6 
2026-01-23 00:00 UT   13 13 10.6   -01 19 55     6.143    6.470  105.2    8.4   291   14.6 
2026-01-24 00:00 UT   13 13 18.0   -01 18 48     6.120    6.463  106.1    8.4   291   14.6 
2026-01-25 00:00 UT   13 13 24.8   -01 17 37     6.097    6.455  107.1    8.4   290   14.6 
2026-01-26 00:00 UT   13 13 31.1   -01 16 22     6.074    6.448  108.1    8.3   290   14.5 
2026-01-27 00:00 UT   13 13 36.8   -01 15 02     6.051    6.440  109.1    8.3   290   14.5 
2026-01-28 00:00 UT   13 13 42.0   -01 13 39     6.028    6.433  110.1    8.3   290   14.5 
2026-01-29 00:00 UT   13 13 46.5   -01 12 12     6.005    6.426  111.1    8.2   290   14.5 
2026-01-30 00:00 UT   13 13 50.5   -01 10 41     5.982    6.418  112.1    8.2   290   14.5 

    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.