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	1 Jun 2026	28.0	19.343 AU	19.120 AU	15h48m	+56°10'	101.2°	2.9°	169°

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
2026-05-31 00:00 UT   15 48 48.5   +56 11 04    19.110   19.338  101.5    2.9   170   28.0 
2026-06-01 00:00 UT   15 48 30.0   +56 10 38    19.119   19.342  101.3    2.9   169   28.0 
2026-06-01 02:43 UT   15 48 28.0   +56 10 35    19.120   19.343  101.2    2.9   169   28.0 
2026-06-02 00:00 UT   15 48 11.7   +56 10 09    19.127   19.347  101.0    2.9   168   28.0 
2026-06-03 00:00 UT   15 47 53.5   +56 09 37    19.136   19.352  100.8    3.0   167   28.0 
2026-06-04 00:00 UT   15 47 35.4   +56 09 02    19.145   19.356  100.5    3.0   166   28.0 
2026-06-05 00:00 UT   15 47 17.4   +56 08 24    19.154   19.361  100.2    3.0   165   28.0 
2026-06-06 00:00 UT   15 46 59.5   +56 07 42    19.163   19.365  100.0    3.0   164   28.0 
2026-06-07 00:00 UT   15 46 41.7   +56 06 58    19.172   19.370   99.7    3.0   163   28.0 
2026-06-08 00:00 UT   15 46 24.1   +56 06 11    19.181   19.375   99.5    3.0   162   28.0 
2026-06-09 00:00 UT   15 46 06.6   +56 05 20    19.191   19.379   99.2    3.0   161   28.0 
2026-06-10 00:00 UT   15 45 49.2   +56 04 27    19.200   19.384   98.9    3.0   160   28.0 
2026-06-11 00:00 UT   15 45 32.0   +56 03 30    19.209   19.388   98.6    3.0   159   28.0 

    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.