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	18 Aug 2026	29.9	17.565 AU	18.287 AU	09h45m	+56°32'	43.3°	2.3°	359°

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
2026-08-17 00:00 UT   09 45 04.5   +56 33 09    18.286   17.559   43.0    2.3     0   29.9 
2026-08-18 00:00 UT   09 45 23.7   +56 32 38    18.287   17.564   43.3    2.3   359   29.9 
2026-08-18 02:14 UT   09 45 25.5   +56 32 36    18.287   17.565   43.3    2.3   359   29.9 
2026-08-19 00:00 UT   09 45 42.9   +56 32 10    18.288   17.570   43.6    2.3   358   29.9 
2026-08-20 00:00 UT   09 46 02.1   +56 31 44    18.289   17.575   43.9    2.3   357   29.9 
2026-08-21 00:00 UT   09 46 21.2   +56 31 20    18.290   17.580   44.3    2.3   356   29.9 
2026-08-22 00:00 UT   09 46 40.3   +56 30 58    18.290   17.585   44.7    2.3   354   29.9 
2026-08-23 00:00 UT   09 46 59.4   +56 30 38    18.290   17.591   45.0    2.3   353   29.9 
2026-08-24 00:00 UT   09 47 18.4   +56 30 21    18.290   17.596   45.4    2.3   352   29.9 
2026-08-25 00:00 UT   09 47 37.4   +56 30 05    18.290   17.601   45.8    2.4   351   29.9 
2026-08-26 00:00 UT   09 47 56.4   +56 29 52    18.290   17.607   46.3    2.4   350   29.9 
2026-08-27 00:00 UT   09 48 15.3   +56 29 40    18.289   17.612   46.7    2.4   349   29.9 
2026-08-28 00:00 UT   09 48 34.1   +56 29 31    18.288   17.617   47.1    2.4   348   29.9 

    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.