C/2018 E1 (ATLAS)
ephemeris	date	magn	radius	delta	ra	dec	elong	phase	PA
Nearest approach	7 Mar 2018	17.4	2.723 AU	2.740 AU	04h27m	-45°21'	78.6°	20.9°	94°
Perihelion	18 Apr 2018	17.5	2.689 AU	2.868 AU	05h44m	-27°54'	69.7°	20.5°	115°
Today	25 Jan 2026	27.8	18.757 AU	18.709 AU	16h04m	+51°57'	91.3°	3.0°	300°

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)                : 0.9501030
    q (Perihelion distance)         : 2.6893810
    i (Inclination)                 : 72.48750
    Ω (Longitude of ascending node) : 146.79020
    ω (Argument of perihelion)      : 299.27380
    L (Longitude of perihelion)     : 118.56342
    B (Latitude of perihelion)      : -56.29063
    T (Time of perihelion passage)  : 2458227.05560
    P (Orbital period in years)     : 395.70

    Epoch                           : 2023 Sep 24
    Reference                       : MPC114602

    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
2026-01-24 00:00 UT   16 04 08.1   +51 53 42    18.711   18.751   90.8    3.0   301   27.8 
2026-01-25 00:00 UT   16 04 20.3   +51 56 15    18.710   18.755   91.1    3.0   300   27.8 
2026-01-25 10:20 UT   16 04 25.5   +51 57 21    18.709   18.757   91.3    3.0   300   27.8 
2026-01-26 00:00 UT   16 04 32.3   +51 58 49    18.708   18.760   91.5    3.0   299   27.8 
2026-01-27 00:00 UT   16 04 43.9   +52 01 25    18.707   18.765   91.8    3.0   299   27.8 
2026-01-28 00:00 UT   16 04 55.2   +52 04 03    18.706   18.769   92.2    3.0   298   27.8 
2026-01-29 00:00 UT   16 05 06.2   +52 06 42    18.704   18.774   92.5    3.0   297   27.8 
2026-01-30 00:00 UT   16 05 17.0   +52 09 22    18.703   18.779   92.9    3.0   296   27.8 
2026-01-31 00:00 UT   16 05 27.4   +52 12 04    18.702   18.783   93.2    3.0   295   27.8 
2026-02-01 00:00 UT   16 05 37.5   +52 14 47    18.701   18.788   93.5    3.0   294   27.8 
2026-02-02 00:00 UT   16 05 47.3   +52 17 32    18.700   18.793   93.9    3.0   293   27.8 
2026-02-03 00:00 UT   16 05 56.8   +52 20 17    18.699   18.797   94.2    3.0   292   27.8 
2026-02-04 00:00 UT   16 06 06.0   +52 23 04    18.697   18.802   94.6    3.0   291   27.8 

    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.