C/2018 E1 (ATLAS)
ephemeris	date	magn	radius	delta	ra	dec	elong	phase	PA
Nearest approach	6 Mar 2018	17.4	2.733 AU	2.743 AU	04h27m	-45°32'	79.0°	20.9°	93°
Perihelion	18 Apr 2018	17.5	2.698 AU	2.872 AU	05h44m	-27°53'	69.9°	20.5°	115°
Today	5 Oct 2026	28.2	19.918 AU	20.271 AU	15h43m	+51°29'	68.0°	2.7°	49°

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 12.0 + 5 log[∆] + 7.5 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/2018 E1 (ATLAS) are:

    e (Eccentricity)                : 0.9502000
    q (Perihelion distance)         : 2.6983190
    i (Inclination)                 : 72.43440
    Ω (Longitude of ascending node) : 146.57330
    ω (Argument of perihelion)      : 299.43320
    L (Longitude of perihelion)     : 118.43189
    B (Latitude of perihelion)      : -56.13158
    T (Time of perihelion passage)  : 2458226.54060
    P (Orbital period in years)     : 398.84

    Epoch                           : 2026 May 29
    Reference                       : MPC194155

    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
2026-10-04 00:00 UT   15 43 12.2   +51 32 48    20.261   19.911   68.1    2.7    51   28.2 
2026-10-05 00:00 UT   15 43 27.1   +51 30 39    20.267   19.915   68.0    2.7    50   28.2 
2026-10-05 13:55 UT   15 43 35.9   +51 29 26    20.271   19.918   68.0    2.7    49   28.2 
2026-10-06 00:00 UT   15 43 42.3   +51 28 32    20.273   19.920   67.9    2.7    49   28.2 
2026-10-07 00:00 UT   15 43 57.7   +51 26 27    20.279   19.924   67.9    2.7    48   28.2 
2026-10-08 00:00 UT   15 44 13.2   +51 24 23    20.284   19.929   67.8    2.7    47   28.2 
2026-10-09 00:00 UT   15 44 29.0   +51 22 21    20.290   19.933   67.7    2.7    46   28.2 
2026-10-10 00:00 UT   15 44 44.9   +51 20 22    20.295   19.938   67.7    2.7    45   28.2 
2026-10-11 00:00 UT   15 45 01.0   +51 18 24    20.301   19.942   67.6    2.7    44   28.2 
2026-10-12 00:00 UT   15 45 17.3   +51 16 28    20.306   19.947   67.5    2.7    43   28.2 
2026-10-13 00:00 UT   15 45 33.7   +51 14 34    20.311   19.951   67.5    2.6    42   28.2 
2026-10-14 00:00 UT   15 45 50.4   +51 12 41    20.316   19.956   67.5    2.6    41   28.2 
2026-10-15 00:00 UT   15 46 07.2   +51 10 51    20.321   19.960   67.4    2.6    40   28.2 

    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.