126P/IRAS
ephemeris	date	magn	radius	delta	ra	dec	elong	phase	PA
Perihelion	4 Jul 2023	14.3	1.711 AU	1.719 AU	01h55m	+09°08'	72.3°	34.5°	249°
Nearest approach	18 Sep 2023	14.3	1.895 AU	1.283 AU	02h34m	+57°04'	111.2°	29.6°	228°
Today	22 Dec 2025	26.0	6.645 AU	6.237 AU	11h25m	+35°35'	110.4°	8.0°	285°

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 9.6 + 5 log[∆] + 15.0 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 126P/IRAS are:

    e (Eccentricity)                : 0.6958690
    q (Perihelion distance)         : 1.7108800
    i (Inclination)                 : 45.87220
    Ω (Longitude of ascending node) : 357.85640
    ω (Argument of perihelion)      : 356.54770
    L (Longitude of perihelion)     : 355.45120
    B (Latitude of perihelion)      : -2.47729
    T (Time of perihelion passage)  : 2460130.31880
    P (Orbital period in years)     : 13.34

    Epoch                           : 2025 Dec 21
    Reference                       : MPEC 2025-W75

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

Ephemerides

Date       Time       RA (2000)    DEC (2000)    delta   radius  elong  phase   PA    magn
2025-12-21 00:00 UT   11 25 32.9   +35 30 56     6.250    6.639  109.2    8.0   286   26.0 
2025-12-22 00:00 UT   11 25 28.6   +35 34 16     6.240    6.643  110.1    8.0   285   26.0 
2025-12-22 08:07 UT   11 25 27.0   +35 35 24     6.237    6.645  110.4    8.0   285   26.0 
2025-12-23 00:00 UT   11 25 23.6   +35 37 39     6.231    6.647  111.0    7.9   284   26.0 
2025-12-24 00:00 UT   11 25 17.7   +35 41 05     6.221    6.651  111.9    7.9   284   26.0 
2025-12-25 00:00 UT   11 25 11.1   +35 44 34     6.212    6.656  112.8    7.8   283   26.0 
2025-12-26 00:00 UT   11 25 03.8   +35 48 06     6.203    6.660  113.7    7.8   283   26.0 
2025-12-27 00:00 UT   11 24 55.6   +35 51 40     6.194    6.664  114.6    7.7   282   26.0 
2025-12-28 00:00 UT   11 24 46.7   +35 55 17     6.185    6.668  115.5    7.6   281   26.0 
2025-12-29 00:00 UT   11 24 37.0   +35 58 56     6.176    6.672  116.4    7.6   281   26.0 
2025-12-30 00:00 UT   11 24 26.5   +36 02 38     6.167    6.676  117.3    7.5   280   26.0 
2025-12-31 00:00 UT   11 24 15.2   +36 06 21     6.159    6.680  118.2    7.5   279   26.0 
2026-01-01 00:00 UT   11 24 03.1   +36 10 06     6.151    6.684  119.1    7.4   279   26.0 

    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.