A/2020 H9
ephemeris	date	magn	radius	delta	ra	dec	elong	phase	PA
Perihelion	21 Dec 2019	22.4	2.560 AU	3.422 AU	16h52m	-44°23'	24.5°	9.2°	216°
Nearest approach	22 Apr 2020	21.2	2.873 AU	1.888 AU	14h32m	-24°28'	165.7°	5.0°	327°
Today	17 Oct 2026	30.0	17.881 AU	18.055 AU	10h01m	+57°09'	78.3°	3.1°	308°

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. The displayed light curve is calculated under the assumption that the object remains inactive. (H=17.10; G=.15).

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 A/2020 H9 are:

    e (Eccentricity)                : 0.9921840
    q (Perihelion distance)         : 2.5595730
    i (Inclination)                 : 137.87070
    Ω (Longitude of ascending node) : 213.04780
    ω (Argument of perihelion)      : 312.52150
    L (Longitude of perihelion)     : 252.01168
    B (Latitude of perihelion)      : -29.63019
    T (Time of perihelion passage)  : 2458838.73850
    P (Orbital period in years)     : 5926.17

    Epoch                           : 2026 May 29
    Reference                       : MPC194167

    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
2026-10-16 00:00 UT   10 01 08.9   +57 07 50    18.063   17.875   77.5    3.1   309   30.0 
2026-10-17 00:00 UT   10 01 18.8   +57 09 33    18.056   17.880   78.3    3.1   308   30.0 
2026-10-17 02:36 UT   10 01 19.8   +57 09 44    18.055   17.881   78.3    3.1   308   30.0 
2026-10-18 00:00 UT   10 01 28.4   +57 11 18    18.048   17.885   79.0    3.1   308   30.0 
2026-10-19 00:00 UT   10 01 37.8   +57 13 05    18.041   17.891   79.7    3.1   307   30.0 
2026-10-20 00:00 UT   10 01 46.8   +57 14 54    18.033   17.896   80.5    3.1   306   30.0 
2026-10-21 00:00 UT   10 01 55.5   +57 16 45    18.026   17.901   81.2    3.2   306   30.0 
2026-10-22 00:00 UT   10 02 03.9   +57 18 38    18.018   17.906   81.9    3.2   305   30.0 
2026-10-23 00:00 UT   10 02 11.9   +57 20 33    18.011   17.911   82.7    3.2   304   30.0 
2026-10-24 00:00 UT   10 02 19.7   +57 22 30    18.003   17.917   83.4    3.2   304   30.0 
2026-10-25 00:00 UT   10 02 27.1   +57 24 29    17.996   17.922   84.1    3.2   303   30.0 
2026-10-26 00:00 UT   10 02 34.2   +57 26 30    17.988   17.927   84.9    3.2   302   30.0 
2026-10-27 00:00 UT   10 02 40.9   +57 28 33    17.980   17.932   85.6    3.2   302   30.0 

    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.