C/2019 K4 (Ye)
ephemeris	date	magn	radius	delta	ra	dec	elong	phase	PA
Perihelion	15 Jun 2019	16.8	2.276 AU	2.720 AU	01h25m	+42°56'	54.0°	21.2°	271°
Nearest approach	16 Sep 2019	16.0	2.510 AU	1.525 AU	00h13m	+09°07'	165.1°	5.9°	219°
Today	2 Aug 2025	29.4	16.833 AU	16.737 AU	08h44m	-75°54'	93.7°	3.4°	181°

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/2019 K4 (Ye) are:

            e (Eccentricity)                : 0.9986120
            q (Perihelion distance)         : 2.2759450
            i (Inclination)                 : 105.28650
            Ω (Longitude of ascending node) : 180.30920
            ω (Argument of perihelion)      : 140.02590
            L (Longitude of perihelion)     : 192.77246
            B (Latitude of perihelion)      : 38.29506
            T (Time of perihelion passage)  : 2458649.80560
            P (Orbital period in years)     : 66398.53

            Epoch                           : 2025 Jul 31
            Reference                       : MPC119997

            Classification(s):              : Nearly isotropic; Returning (a < 10000 AU); External (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 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 (12.50 + 5 log[∆] + 10.00 log[r]), whereas the red curve is being recalculated every 6 hours based on the available COBS/MPC observations (currently 11.05 + 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
2025-08-02 00:00 UT   08 43 42.5   -75 55 03    16.734   16.831   93.8    3.4   181   29.4 
2025-08-02 08:42 UT   08 44 04.6   -75 54 59    16.737   16.833   93.7    3.4   181   29.4 
2025-08-03 00:00 UT   08 44 43.3   -75 54 53    16.744   16.837   93.5    3.4   182   29.4 
2025-08-04 00:00 UT   08 45 44.0   -75 54 46    16.754   16.842   93.2    3.4   182   29.4 
2025-08-05 00:00 UT   08 46 44.5   -75 54 41    16.764   16.848   93.0    3.4   183   29.4 
2025-08-06 00:00 UT   08 47 44.9   -75 54 39    16.774   16.853   92.7    3.4   184   29.4 
2025-08-07 00:00 UT   08 48 45.2   -75 54 39    16.784   16.859   92.5    3.4   184   29.4 
2025-08-08 00:00 UT   08 49 45.3   -75 54 42    16.794   16.864   92.2    3.4   185   29.4 
2025-08-09 00:00 UT   08 50 45.2   -75 54 47    16.804   16.870   91.9    3.4   186   29.4 
2025-08-10 00:00 UT   08 51 45.0   -75 54 55    16.815   16.875   91.7    3.4   187   29.4 
2025-08-11 00:00 UT   08 52 44.6   -75 55 06    16.825   16.881   91.4    3.4   187   29.5 
2025-08-12 00:00 UT   08 53 44.1   -75 55 19    16.835   16.886   91.1    3.4   188   29.5 

    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.