C/2017 W2 (Leonard)
ephemeris	date	magn	radius	delta	ra	dec	elong	phase	PA
Perihelion	31 Oct 2017	20.1	3.945 AU	4.176 AU	10h17m	+21°47'	69.8°	13.7°	295°
Nearest approach	29 Jan 2018	19.4	3.999 AU	3.018 AU	08h57m	+12°19'	173.7°	1.5°	334°
Today	23 Apr 2024	27.8	13.118 AU	13.362 AU	00h40m	-59°13'	73.8°	4.2°	201°

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 W2 (Leonard) are:

            e (Eccentricity)                : 0.7101490
            q (Perihelion distance)         : 3.9445230
            i (Inclination)                 : 98.21000
            Ω (Longitude of ascending node) : 312.80870
            ω (Argument of perihelion)      : 168.86980
            L (Longitude of perihelion)     : 314.41799
            B (Latitude of perihelion)      : 11.01470
            T (Time of perihelion passage)  : 2458057.70080
            P (Orbital period in years)     : 50.20

            Epoch                           : 2022 Nov 15
            Reference                       : MPC114600

            Classification(s):              : Nearly isotropic; Returning (a < 10000 AU); Halley type (P < 200 years)
        

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 light curve is based on the absolute magnitude and slope parameter as calculated from an MPEC, or the latest values provided by the minor planet center. (11.00 + 5 log[∆] + 10.00 log[r]).

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
2024-04-23 00:00 UT   00 40 03.4   -59 13 09    13.364   13.117   73.7    4.2   201   27.8 
2024-04-23 08:25 UT   00 40 11.5   -59 13 17    13.362   13.118   73.8    4.2   201   27.8 
2024-04-24 00:00 UT   00 40 26.4   -59 13 34    13.359   13.120   74.2    4.2   202   27.8 
2024-04-25 00:00 UT   00 40 49.3   -59 14 04    13.354   13.124   74.7    4.2   203   27.8 
2024-04-26 00:00 UT   00 41 11.9   -59 14 37    13.349   13.127   75.2    4.2   203   27.8 
2024-04-27 00:00 UT   00 41 34.4   -59 15 14    13.343   13.131   75.7    4.3   204   27.8 
2024-04-28 00:00 UT   00 41 56.6   -59 15 55    13.338   13.134   76.2    4.3   205   27.8 
2024-04-29 00:00 UT   00 42 18.7   -59 16 39    13.333   13.137   76.7    4.3   206   27.8 
2024-04-30 00:00 UT   00 42 40.5   -59 17 27    13.328   13.141   77.2    4.3   207   27.8 
2024-05-01 00:00 UT   00 43 02.2   -59 18 19    13.322   13.144   77.7    4.3   207   27.8 
2024-05-02 00:00 UT   00 43 23.6   -59 19 15    13.317   13.148   78.2    4.3   208   27.8 
2024-05-03 00:00 UT   00 43 44.7   -59 20 14    13.311   13.151   78.7    4.3   209   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.