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	9 May 2025	32.0	22.240 AU	22.611 AU	04h31m	-46°57'	67.2°	2.4°	157°

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.)

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)
        

The light curve chart below shows the estimated development of the comet's magnitude. Blue and black dots are visual and photometric CCD observations respectively from COBS or the MPC. The gray curve is based on the absolute magnitude and slope parameter as calculated from the original MPEC, or the latest values provided by the MPC (17.00 + 5 log[∆] + 10.00 log[r]), whereas the red curve is being recalculated every 6 hours based on the available COBS/MPC observations (currently 11.72 + 5 log[∆] + 10.00 log[r]). The additional green curve shows the effect of forward scattering, occurring when the comet is between the earth and the sun, for a gas-to-dust light ratio δ90 of 0.30. (See Marcus 2007)

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.
A more printer-friendly version of the same chart can be found further down this page as well.

The following chart shows the current location of the comet in a smaller, upside-down telescopic field of view.

A printable version of the short-term path of the comet in a field of view that is optimized for (~10x50) binoculars and finderscopes.

Ephemerides:

Date       Time       RA (2000)    DEC (2000)    delta   radius  elong  phase   PA    magn
2025-05-09 00:00 UT   04 31 11.0   -46 57 32    22.609   22.238   67.2    2.4   157   32.0 
2025-05-09 05:24 UT   04 31 14.2   -46 57 19    22.611   22.240   67.2    2.4   157   32.0 
2025-05-10 00:00 UT   04 31 25.3   -46 56 39    22.615   22.244   67.2    2.4   158   32.0 
2025-05-11 00:00 UT   04 31 39.8   -46 55 48    22.620   22.249   67.2    2.4   159   32.0 
2025-05-12 00:00 UT   04 31 54.3   -46 54 59    22.625   22.254   67.2    2.4   160   32.0 
2025-05-13 00:00 UT   04 32 08.9   -46 54 13    22.630   22.259   67.3    2.4   161   32.0 
2025-05-14 00:00 UT   04 32 23.5   -46 53 28    22.634   22.264   67.3    2.4   162   32.0 
2025-05-15 00:00 UT   04 32 38.2   -46 52 46    22.639   22.270   67.3    2.4   163   32.0 
2025-05-16 00:00 UT   04 32 52.9   -46 52 07    22.644   22.275   67.4    2.4   164   32.0 
2025-05-17 00:00 UT   04 33 07.7   -46 51 29    22.648   22.280   67.4    2.4   165   32.0 
2025-05-18 00:00 UT   04 33 22.6   -46 50 54    22.653   22.285   67.5    2.4   166   32.0 
2025-05-19 00:00 UT   04 33 37.5   -46 50 21    22.657   22.290   67.5    2.4   167   32.0 

    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.