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	23 Aug 2025	29.5	16.947 AU	16.951 AU	09h04m	-76°00'	88.0°	3.4°	196°

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)                : 0.9986160
            q (Perihelion distance)         : 2.2759920
            i (Inclination)                 : 105.28580
            Ω (Longitude of ascending node) : 180.31510
            ω (Argument of perihelion)      : 140.02820
            L (Longitude of perihelion)     : 192.77684
            B (Latitude of perihelion)      : 38.29305
            T (Time of perihelion passage)  : 2458649.81210
            P (Orbital period in years)     : 66688.66

            Epoch                           : 2025 Aug 21
            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
2025-08-23 00:00 UT   09 04 25.9   -76 00 31    16.950   16.946   88.1    3.4   195   29.5 
2025-08-23 03:44 UT   09 04 34.8   -76 00 38    16.951   16.947   88.0    3.4   196   29.5 
2025-08-24 00:00 UT   09 05 22.9   -76 01 15    16.960   16.952   87.8    3.4   196   29.5 
2025-08-25 00:00 UT   09 06 19.7   -76 02 01    16.971   16.957   87.5    3.4   197   29.5 
2025-08-26 00:00 UT   09 07 16.3   -76 02 50    16.981   16.963   87.2    3.4   198   29.5 
2025-08-27 00:00 UT   09 08 12.6   -76 03 41    16.992   16.968   86.9    3.4   198   29.5 
2025-08-28 00:00 UT   09 09 08.7   -76 04 35    17.002   16.974   86.7    3.4   199   29.5 
2025-08-29 00:00 UT   09 10 04.5   -76 05 31    17.013   16.979   86.4    3.4   200   29.5 
2025-08-30 00:00 UT   09 10 60.0   -76 06 29    17.023   16.985   86.1    3.4   200   29.5 
2025-08-31 00:00 UT   09 11 55.2   -76 07 30    17.034   16.990   85.8    3.4   201   29.5 
2025-09-01 00:00 UT   09 12 50.1   -76 08 34    17.044   16.996   85.5    3.4   202   29.5 
2025-09-02 00:00 UT   09 13 44.8   -76 09 40    17.055   17.001   85.2    3.4   202   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.