C/2017 E4 (Lovejoy)
ephemeris	date	magn	radius	delta	ra	dec	elong	phase	PA
Nearest approach	30 Mar 2017	9.2	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	25 Apr 2024	31.3	20.231 AU	20.607 AU	04h25m	-46°20'	66.7°	2.6°	144°

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 11.67 + 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
2024-04-25 00:00 UT   04 25 08.3   -46 20 48    20.604   20.229   66.7    2.6   144   31.3 
2024-04-25 09:27 UT   04 25 13.9   -46 20 13    20.607   20.231   66.7    2.6   144   31.3 
2024-04-26 00:00 UT   04 25 22.4   -46 19 21    20.611   20.234   66.7    2.6   145   31.3 
2024-04-27 00:00 UT   04 25 36.7   -46 17 57    20.618   20.239   66.6    2.6   146   31.3 
2024-04-28 00:00 UT   04 25 51.0   -46 16 34    20.624   20.245   66.5    2.6   147   31.3 
2024-04-29 00:00 UT   04 26 05.5   -46 15 14    20.631   20.250   66.5    2.6   148   31.3 
2024-04-30 00:00 UT   04 26 20.1   -46 13 56    20.637   20.256   66.4    2.6   149   31.3 
2024-05-01 00:00 UT   04 26 34.8   -46 12 40    20.643   20.261   66.4    2.6   150   31.3 
2024-05-02 00:00 UT   04 26 49.6   -46 11 27    20.650   20.267   66.3    2.6   151   31.3 
2024-05-03 00:00 UT   04 27 04.5   -46 10 15    20.656   20.272   66.3    2.6   152   31.3 
2024-05-04 00:00 UT   04 27 19.6   -46 09 06    20.662   20.277   66.3    2.6   153   31.3 
2024-05-05 00:00 UT   04 27 34.7   -46 07 59    20.668   20.283   66.2    2.6   154   31.3 

    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.