C/2025 L1 (ATLAS)
ephemeris	date	magn	radius	delta	ra	dec	elong	phase	PA
Perihelion	12 Jan 2026	18.2	1.680 AU	2.132 AU	15h53m	-33°55'	50.1°	26.7°	271°
Nearest approach	23 Mar 2026	17.3	1.911 AU	1.102 AU	15h07m	+20°26'	131.2°	23.1°	250°
Today	5 Apr 2026	17.6	1.996 AU	1.175 AU	14h23m	+36°21'	133.0°	21.5°	210°

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 14.3 + 5 log[∆] + 10.0 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 C/2025 L1 (ATLAS) are:

    e (Eccentricity)                : 1.0014740
    q (Perihelion distance)         : 1.6796800
    i (Inclination)                 : 114.13580
    Ω (Longitude of ascending node) : 208.11020
    ω (Argument of perihelion)      : 341.25170
    L (Longitude of perihelion)     : 216.01178
    B (Latitude of perihelion)      : -17.05642
    T (Time of perihelion passage)  : 2461053.23630

    Epoch                           : 2026 Apr 04
    Reference                       : MPEC 2026-FC3

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

Ephemerides

Date       Time       RA (2000)    DEC (2000)    delta   radius  elong  phase   PA    magn
2026-04-04 00:00 UT   14 27 38.5   +35 05 38     1.162    1.988  133.5   21.4   214   17.6 
2026-04-05 00:00 UT   14 23 46.6   +36 09 46     1.173    1.995  133.1   21.5   211   17.6 
2026-04-05 04:40 UT   14 23 01.1   +36 21 60     1.175    1.996  133.0   21.5   210   17.6 
2026-04-06 00:00 UT   14 19 51.4   +37 11 49     1.184    2.001  132.6   21.6   208   17.7 
2026-04-07 00:00 UT   14 15 53.1   +38 11 41     1.196    2.008  132.0   21.7   205   17.7 
2026-04-08 00:00 UT   14 11 52.1   +39 09 21     1.208    2.015  131.4   21.9   202   17.7 
2026-04-09 00:00 UT   14 07 48.6   +40 04 47     1.222    2.022  130.7   22.1   199   17.8 
2026-04-10 00:00 UT   14 03 43.2   +40 57 57     1.235    2.029  129.9   22.2   196   17.8 
2026-04-11 00:00 UT   13 59 36.0   +41 48 51     1.250    2.037  129.1   22.4   194   17.9 
2026-04-12 00:00 UT   13 55 27.7   +42 37 28     1.265    2.044  128.3   22.6   191   17.9 
2026-04-13 00:00 UT   13 51 18.5   +43 23 49     1.281    2.051  127.4   22.9   188   17.9 
2026-04-14 00:00 UT   13 47 08.8   +44 07 55     1.297    2.058  126.5   23.1   186   18.0 
2026-04-15 00:00 UT   13 42 59.2   +44 49 49     1.314    2.065  125.5   23.3   184   18.0 

    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.