C/2017 E4 (Lovejoy)
ephemeris	date	magn	radius	delta	ra	dec	elong	phase	PA
Nearest approach	30 Mar 2017	9.3	0.743 AU	0.601 AU	21h24m	+05°50'	47.8°	95.4°	270°
Perihelion	23 Apr 2017	8.8	0.492 AU	1.100 AU	01h14m	+36°41'	26.6°	66.0°	332°
Today	27 Oct 2025	32.2	23.120 AU	22.808 AU	04h47m	-51°14'	107.1°	2.4°	319°

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 11.7 + 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/2017 E4 (Lovejoy) are:

    e (Eccentricity)                : 1.0014810
    q (Perihelion distance)         : 0.4922180
    i (Inclination)                 : 87.96240
    Ω (Longitude of ascending node) : 222.76090
    ω (Argument of perihelion)      : 87.09480
    L (Longitude of perihelion)     : 257.77653
    B (Latitude of perihelion)      : 86.45198
    T (Time of perihelion passage)  : 2457866.76760

    Epoch                           : 2022 May 26
    Reference                       : MPC105239

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

Ephemerides

Date       Time       RA (2000)    DEC (2000)    delta   radius  elong  phase   PA    magn
2025-10-26 00:00 UT   04 47 42.1   -51 12 04    22.803   23.112  106.9    2.4   317   32.1 
2025-10-27 00:00 UT   04 47 29.6   -51 13 47    22.806   23.117  107.0    2.4   318   32.1 
2025-10-27 11:11 UT   04 47 23.7   -51 14 35    22.808   23.120  107.1    2.4   319   32.2 
2025-10-28 00:00 UT   04 47 16.9   -51 15 29    22.810   23.123  107.1    2.4   319   32.2 
2025-10-29 00:00 UT   04 47 03.9   -51 17 09    22.814   23.128  107.2    2.4   321   32.2 
2025-10-30 00:00 UT   04 46 50.8   -51 18 46    22.818   23.133  107.3    2.3   322   32.2 
2025-10-31 00:00 UT   04 46 37.5   -51 20 22    22.822   23.138  107.3    2.3   323   32.2 
2025-11-01 00:00 UT   04 46 24.1   -51 21 55    22.826   23.143  107.4    2.3   324   32.2 
2025-11-02 00:00 UT   04 46 10.5   -51 23 26    22.830   23.148  107.5    2.3   325   32.2 
2025-11-03 00:00 UT   04 45 56.7   -51 24 55    22.834   23.153  107.5    2.3   326   32.2 
2025-11-04 00:00 UT   04 45 42.7   -51 26 21    22.839   23.158  107.6    2.3   327   32.2 
2025-11-05 00:00 UT   04 45 28.6   -51 27 45    22.843   23.163  107.6    2.3   328   32.2 
2025-11-06 00:00 UT   04 45 14.3   -51 29 07    22.848   23.168  107.6    2.3   329   32.2 

    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.