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	1 Nov 2025	37.5	17.524 AU	18.115 AU	11h05m	+00°26'	52.1°	2.6°	289°

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
2025-10-31 00:00 UT   11 05 38.3   +00 28 13    18.128   17.512   50.3    2.5   289   37.5 
2025-11-01 00:00 UT   11 05 45.7   +00 27 15    18.121   17.518   51.3    2.5   289   37.5 
2025-11-01 21:05 UT   11 05 52.0   +00 26 24    18.115   17.524   52.1    2.6   289   37.5 
2025-11-02 00:00 UT   11 05 52.8   +00 26 17    18.114   17.525   52.3    2.6   289   37.5 
2025-11-03 00:00 UT   11 05 59.8   +00 25 20    18.107   17.531   53.2    2.6   289   37.5 
2025-11-04 00:00 UT   11 06 06.6   +00 24 24    18.099   17.538   54.2    2.6   289   37.5 
2025-11-05 00:00 UT   11 06 13.3   +00 23 29    18.091   17.544   55.1    2.7   289   37.5 
2025-11-06 00:00 UT   11 06 19.7   +00 22 35    18.083   17.550   56.1    2.7   290   37.5 
2025-11-07 00:00 UT   11 06 26.0   +00 21 41    18.075   17.557   57.1    2.7   290   37.5 
2025-11-08 00:00 UT   11 06 32.2   +00 20 49    18.067   17.563   58.0    2.7   290   37.5 
2025-11-09 00:00 UT   11 06 38.1   +00 19 57    18.058   17.569   59.0    2.8   290   37.5 
2025-11-10 00:00 UT   11 06 43.9   +00 19 07    18.050   17.576   60.0    2.8   290   37.5 
2025-11-11 00:00 UT   11 06 49.5   +00 18 17    18.041   17.582   61.0    2.8   290   37.5 

    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.