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	27 Jul 2024	31.4	20.731 AU	20.842 AU	04h48m	-46°55'	82.3°	2.8°	231°

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
2024-07-27 00:00 UT   04 48 06.1   -46 55 15    20.842   20.730   82.3    2.8   231   31.4 
2024-07-27 03:16 UT   04 48 07.5   -46 55 32    20.842   20.731   82.3    2.8   231   31.4 
2024-07-28 00:00 UT   04 48 16.4   -46 57 21    20.841   20.736   82.6    2.8   232   31.4 
2024-07-29 00:00 UT   04 48 26.5   -46 59 30    20.841   20.741   82.9    2.8   233   31.4 
2024-07-30 00:00 UT   04 48 36.5   -47 01 40    20.840   20.746   83.3    2.8   233   31.4 
2024-07-31 00:00 UT   04 48 46.2   -47 03 52    20.840   20.752   83.6    2.8   234   31.4 
2024-08-01 00:00 UT   04 48 55.7   -47 06 05    20.839   20.757   83.9    2.8   235   31.4 
2024-08-02 00:00 UT   04 49 05.0   -47 08 20    20.838   20.762   84.3    2.8   236   31.4 
2024-08-03 00:00 UT   04 49 14.1   -47 10 37    20.838   20.768   84.6    2.8   237   31.4 
2024-08-04 00:00 UT   04 49 23.0   -47 12 55    20.837   20.773   85.0    2.8   238   31.4 
2024-08-05 00:00 UT   04 49 31.6   -47 15 15    20.836   20.778   85.3    2.8   239   31.4 
2024-08-06 00:00 UT   04 49 40.0   -47 17 36    20.836   20.784   85.6    2.8   239   31.4 

    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.