C/2023 E1 (ATLAS)
ephemeris	date	magn	radius	delta	ra	dec	elong	phase	PA
Perihelion	30 Jun 2023	10.6	1.026 AU	0.644 AU	14h46m	+80°01'	72.4°	70.8°	126°
Nearest approach	17 Aug 2023	10.4	1.287 AU	0.376 AU	21h48m	+36°28'	130.1°	37.0°	181°
Today	5 Oct 2026	26.7	10.595 AU	10.050 AU	04h25m	-18°01'	120.6°	4.7°	287°

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 11.5 + 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/2023 E1 (ATLAS) are:

    e (Eccentricity)                : 0.9465100
    q (Perihelion distance)         : 1.0261230
    i (Inclination)                 : 38.29020
    Ω (Longitude of ascending node) : 164.55990
    ω (Argument of perihelion)      : 105.87450
    L (Longitude of perihelion)     : 94.47622
    B (Latitude of perihelion)      : 36.58492
    T (Time of perihelion passage)  : 2460126.22300
    P (Orbital period in years)     : 84.02

    Epoch                           : 2026 May 29
    Reference                       : MPC194184

    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
2026-10-04 00:00 UT   04 26 00.5   -17 57 04    10.055   10.587  119.7    4.7   286   26.7 
2026-10-05 00:00 UT   04 25 49.6   -18 00 30    10.051   10.593  120.4    4.7   287   26.7 
2026-10-05 06:35 UT   04 25 46.5   -18 01 27    10.050   10.595  120.6    4.7   287   26.7 
2026-10-06 00:00 UT   04 25 38.3   -18 03 55    10.047   10.599  121.1    4.6   288   26.7 
2026-10-07 00:00 UT   04 25 26.7   -18 07 18    10.044   10.605  121.8    4.6   288   26.7 
2026-10-08 00:00 UT   04 25 14.7   -18 10 39    10.040   10.611  122.5    4.6   289   26.7 
2026-10-09 00:00 UT   04 25 02.3   -18 13 59    10.037   10.617  123.2    4.5   290   26.7 
2026-10-10 00:00 UT   04 24 49.6   -18 17 17    10.034   10.623  123.8    4.5   291   26.7 
2026-10-11 00:00 UT   04 24 36.5   -18 20 34    10.031   10.629  124.5    4.4   292   26.7 
2026-10-12 00:00 UT   04 24 23.1   -18 23 48    10.028   10.635  125.1    4.4   293   26.7 
2026-10-13 00:00 UT   04 24 09.4   -18 27 01    10.026   10.640  125.8    4.4   294   26.7 
2026-10-14 00:00 UT   04 23 55.3   -18 30 12    10.023   10.646  126.4    4.3   295   26.7 
2026-10-15 00:00 UT   04 23 40.9   -18 33 20    10.021   10.652  127.1    4.3   296   26.7 

    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.