C/2019 D1 (Flewelling)
ephemeris	date	magn	radius	delta	ra	dec	elong	phase	PA
Perihelion	8 May 2019	14.7	1.592 AU	1.640 AU	22h03m	+21°15'	69.3°	36.3°	259°
Nearest approach	10 Sep 2019	17.4	2.283 AU	1.561 AU	01h12m	+44°13'	124.0°	21.5°	217°
Today	21 Oct 2025	39.0	17.748 AU	17.235 AU	05h46m	+03°08'	119.6°	2.8°	281°

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.)

Light curve

The light curve chart below shows the estimated development of the comet's magnitude. Blue and black dots are visual and photometric CCD observations from COBS. This lightcurve is being recalculated every 6 hours based on the available COBS/MPC observations (currently 9.9 + 5 log[∆] + 18.4 log[r]). An additional green curve is displayed when an increase in apparent brightness is expected due to forward scattering of sunlight, which occurs when a dust-rich comet is located between the Earth and the Sun. (See Marcus 2007)

Charts

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.

Orbital elements

The orbital elements of C/2019 D1 (Flewelling) are:

    e (Eccentricity)                : 0.9882470
    q (Perihelion distance)         : 1.5924000
    i (Inclination)                 : 34.02220
    Ω (Longitude of ascending node) : 231.68120
    ω (Argument of perihelion)      : 70.69840
    L (Longitude of perihelion)     : 298.77423
    B (Latitude of perihelion)      : 31.87479
    T (Time of perihelion passage)  : 2458611.87180
    P (Orbital period in years)     : 1577.09

    Epoch                           : 2025 Oct 20
    Reference                       : MPEC 2022-O08

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

Ephemerides

Date       Time       RA (2000)    DEC (2000)    delta   radius  elong  phase   PA    magn
2025-10-20 00:00 UT   05 47 04.9   +03 10 39    17.250   17.739  117.9    2.8   280   39.0 
2025-10-21 00:00 UT   05 46 58.8   +03 09 27    17.241   17.744  118.9    2.8   280   39.0 
2025-10-21 18:31 UT   05 46 54.0   +03 08 31    17.235   17.748  119.6    2.8   281   39.0 
2025-10-22 00:00 UT   05 46 52.6   +03 08 15    17.233   17.749  119.8    2.8   281   39.0 
2025-10-23 00:00 UT   05 46 46.1   +03 07 04    17.225   17.755  120.7    2.8   281   39.0 
2025-10-24 00:00 UT   05 46 39.4   +03 05 53    17.217   17.760  121.7    2.7   282   39.0 
2025-10-25 00:00 UT   05 46 32.5   +03 04 43    17.209   17.765  122.6    2.7   282   39.0 
2025-10-26 00:00 UT   05 46 25.4   +03 03 34    17.201   17.770  123.5    2.7   283   39.0 
2025-10-27 00:00 UT   05 46 18.1   +03 02 25    17.194   17.776  124.5    2.6   283   39.0 
2025-10-28 00:00 UT   05 46 10.6   +03 01 17    17.187   17.781  125.4    2.6   284   39.0 
2025-10-29 00:00 UT   05 46 03.0   +03 00 10    17.180   17.786  126.3    2.6   284   39.0 
2025-10-30 00:00 UT   05 45 55.1   +02 59 03    17.173   17.792  127.2    2.5   285   39.0 
2025-10-31 00:00 UT   05 45 47.0   +02 57 57    17.166   17.797  128.2    2.5   286   39.0 

    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.