C/2020 H5 (Robinson)
ephemeris	date	magn	radius	delta	ra	dec	elong	phase	PA
Perihelion	10 Dec 2020	19.7	9.334 AU	9.790 AU	12h34m	-36°32'	59.9°	5.2°	277°
Nearest approach	11 Apr 2021	19.4	9.359 AU	8.470 AU	12h24m	-34°27'	151.0°	3.0°	29°
Today	18 Apr 2026	22.1	14.076 AU	13.301 AU	15h38m	+18°48'	139.2°	2.7°	226°

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 light curve is based on the absolute magnitude and slope parameter as calculated from an MPEC, or the latest values provided by the minor planet center. (5.0 + 5 log[∆] + 10.0 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/2020 H5 (Robinson) are:

    e (Eccentricity)                : 0.9987510
    q (Perihelion distance)         : 9.3342210
    i (Inclination)                 : 70.20700
    Ω (Longitude of ascending node) : 210.59890
    ω (Argument of perihelion)      : 326.26870
    L (Longitude of perihelion)     : 197.85850
    B (Latitude of perihelion)      : -31.49962
    T (Time of perihelion passage)  : 2459193.67340
    P (Orbital period in years)     : 646060.90

    Epoch                           : 2026 Apr 17
    Reference                       : MPEC 2026-E44

    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
2026-04-17 00:00 UT   15 38 47.2   +18 43 34    13.302   14.070  138.6    2.7   228   22.1 
2026-04-18 00:00 UT   15 38 35.3   +18 46 38    13.301   14.074  139.0    2.7   227   22.1 
2026-04-18 11:19 UT   15 38 29.6   +18 48 04    13.301   14.076  139.2    2.7   226   22.1 
2026-04-19 00:00 UT   15 38 23.2   +18 49 40    13.300   14.078  139.4    2.7   225   22.1 
2026-04-20 00:00 UT   15 38 11.0   +18 52 40    13.300   14.082  139.7    2.6   224   22.1 
2026-04-21 00:00 UT   15 37 58.5   +18 55 38    13.300   14.085  140.1    2.6   222   22.1 
2026-04-22 00:00 UT   15 37 46.0   +18 58 34    13.300   14.089  140.4    2.6   221   22.1 
2026-04-23 00:00 UT   15 37 33.3   +19 01 27    13.301   14.093  140.7    2.6   219   22.1 
2026-04-24 00:00 UT   15 37 20.5   +19 04 18    13.301   14.097  140.9    2.6   217   22.1 
2026-04-25 00:00 UT   15 37 07.5   +19 07 07    13.302   14.100  141.2    2.6   216   22.1 
2026-04-26 00:00 UT   15 36 54.5   +19 09 53    13.303   14.104  141.4    2.5   214   22.1 
2026-04-27 00:00 UT   15 36 41.3   +19 12 37    13.305   14.108  141.6    2.5   213   22.1 
2026-04-28 00:00 UT   15 36 28.0   +19 15 18    13.306   14.112  141.8    2.5   211   22.1 

    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.