C/2020 P4-A (SOHO)
ephemeris	date	magn	radius	delta	ra	dec	elong	phase	PA
Nearest approach	6 Aug 2020	8.3	0.126 AU	0.911 AU	09h22m	+18°45'	4.3°	142.9°	59°
Perihelion	8 Aug 2020	7.1	0.091 AU	0.943 AU	09h00m	+17°09'	3.3°	139.8°	288°
Today	21 Sep 2026	38.2	19.548 AU	20.521 AU	11h00m	+01°15'	13.6°	0.7°	273°

This comet is a sunskirter. Although it may become very bright at perihelion, this will only be for a very short period very close to the sun.

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 18.8 + 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 P4-A (SOHO) are:

    e (Eccentricity)                : 1.0020940
    q (Perihelion distance)         : 0.0907350
    i (Inclination)                 : 26.33730
    Ω (Longitude of ascending node) : 175.20070
    ω (Argument of perihelion)      : 177.47990
    L (Longitude of perihelion)     : 172.94191
    B (Latitude of perihelion)      : 1.11776
    T (Time of perihelion passage)  : 2459069.72160

    Epoch                           : 2021 Feb 13
    Reference                       : MPEC 2020-QN1

    Classification(s):              : Nearly isotropic; New (a > 10000 AU); Sunskirter

Ephemerides

Date       Time       RA (2000)    DEC (2000)    delta   radius  elong  phase   PA    magn
2026-09-20 00:00 UT   11 00 11.4   +01 17 54    20.517   19.536   11.9    0.6   270   38.2 
2026-09-21 00:00 UT   11 00 21.9   +01 16 46    20.519   19.542   12.8    0.7   271   38.2 
2026-09-21 23:40 UT   11 00 32.2   +01 15 40    20.521   19.548   13.6    0.7   273   38.2 
2026-09-22 00:00 UT   11 00 32.3   +01 15 39    20.521   19.548   13.6    0.7   273   38.2 
2026-09-23 00:00 UT   11 00 42.7   +01 14 32    20.523   19.554   14.5    0.7   274   38.2 
2026-09-24 00:00 UT   11 00 53.1   +01 13 24    20.525   19.560   15.4    0.8   275   38.2 
2026-09-25 00:00 UT   11 01 03.3   +01 12 17    20.526   19.566   16.3    0.8   276   38.2 
2026-09-26 00:00 UT   11 01 13.5   +01 11 10    20.527   19.572   17.2    0.9   277   38.2 
2026-09-27 00:00 UT   11 01 23.7   +01 10 03    20.528   19.578   18.1    0.9   278   38.2 
2026-09-28 00:00 UT   11 01 33.8   +01 08 56    20.529   19.585   19.0    1.0   279   38.2 
2026-09-29 00:00 UT   11 01 43.8   +01 07 50    20.529   19.591   19.9    1.0   280   38.2 
2026-09-30 00:00 UT   11 01 53.8   +01 06 43    20.529   19.597   20.8    1.0   280   38.2 
2026-10-01 00:00 UT   11 02 03.7   +01 05 37    20.529   19.603   21.7    1.1   281   38.2 

    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.