A/2025 A1
ephemeris	date	magn	radius	delta	ra	dec	elong	phase	PA
Today	29 Dec 2025	19.2	6.239 AU	5.380 AU	08h49m	+33°08'	148.5°	4.7°	261°
Nearest approach	5 Mar 2027	18.6	5.341 AU	4.515 AU	12h13m	+39°26'	143.1°	6.4°	210°
Perihelion	13 Mar 2027	18.6	5.340 AU	4.522 AU	12h10m	+39°57'	142.0°	6.6°	196°

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=11.20; 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 A1 are:

    e (Eccentricity)                : 1.0018990
    q (Perihelion distance)         : 5.3403660
    i (Inclination)                 : 33.42210
    Ω (Longitude of ascending node) : 101.32930
    ω (Argument of perihelion)      : 68.16900
    L (Longitude of perihelion)     : 165.68973
    B (Latitude of perihelion)      : 30.75058
    T (Time of perihelion passage)  : 2461478.09670

    Epoch                           : 2025 Dec 28
    Reference                       : MPEC 2025-YF1

    Classification(s):              : Nearly isotropic; New (a > 10000 AU)

Ephemerides

Date       Time       RA (2000)    DEC (2000)    delta   radius  elong  phase   PA    magn
2025-12-28 00:00 UT   08 49 51.5   +33 00 40     5.395    6.245  147.2    4.9   262   19.3 
2025-12-29 00:00 UT   08 49 36.1   +33 06 07     5.384    6.241  148.1    4.8   261   19.2 
2025-12-29 08:59 UT   08 49 30.1   +33 08 09     5.380    6.239  148.5    4.7   261   19.2 
2025-12-30 00:00 UT   08 49 20.0   +33 11 34     5.373    6.237  149.0    4.7   260   19.2 
2025-12-31 00:00 UT   08 49 03.4   +33 17 01     5.363    6.233  150.0    4.5   259   19.2 
2026-01-01 00:00 UT   08 48 46.3   +33 22 28     5.353    6.230  150.9    4.4   257   19.2 
2026-01-02 00:00 UT   08 48 28.6   +33 27 55     5.343    6.226  151.8    4.3   256   19.2 
2026-01-03 00:00 UT   08 48 10.4   +33 33 21     5.333    6.222  152.6    4.2   255   19.2 
2026-01-04 00:00 UT   08 47 51.7   +33 38 48     5.323    6.219  153.5    4.0   253   19.2 
2026-01-05 00:00 UT   08 47 32.4   +33 44 13     5.314    6.215  154.4    3.9   251   19.2 
2026-01-06 00:00 UT   08 47 12.7   +33 49 38     5.305    6.211  155.2    3.8   250   19.1 
2026-01-07 00:00 UT   08 46 52.5   +33 55 02     5.297    6.208  156.0    3.7   248   19.1 
2026-01-08 00:00 UT   08 46 31.8   +34 00 25     5.288    6.204  156.8    3.6   246   19.1 

    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.