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	12 Jul 2025	37.2	16.799 AU	17.401 AU	10h45m	+02°28'	52.3°	2.7°	116°

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.)

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
        

The light curve chart below shows the estimated development of the comet's magnitude. Blue and black dots are visual and photometric CCD observations respectively from COBS or the MPC. The gray curve is based on the absolute magnitude and slope parameter as calculated from the original MPEC, or the latest values provided by the MPC (5.30 + 5 log[∆] + 15.00 log[r]), whereas the red curve is being recalculated every 6 hours based on the available COBS/MPC observations (currently 18.75 + 5 log[∆] + 10.00 log[r]). The additional green curve shows the effect of forward scattering, occurring when the comet is between the earth and the sun, for a gas-to-dust light ratio δ90 of 0.30. (See Marcus 2007)

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.
A more printer-friendly version of the same chart can be found further down this page as well.

The following chart shows the current location of the comet in a smaller, upside-down telescopic field of view.

A printable version of the short-term path of the comet in a field of view that is optimized for (~10x50) binoculars and finderscopes.

Ephemerides:

Date       Time       RA (2000)    DEC (2000)    delta   radius  elong  phase   PA    magn
2025-07-12 00:00 UT   10 45 38.2   +02 28 32    17.396   16.797   52.5    2.8   116   37.2 
2025-07-12 06:09 UT   10 45 40.4   +02 28 23    17.401   16.799   52.3    2.7   116   37.2 
2025-07-13 00:00 UT   10 45 46.8   +02 27 57    17.416   16.804   51.6    2.7   116   37.2 
2025-07-14 00:00 UT   10 45 55.5   +02 27 20    17.435   16.810   50.7    2.7   116   37.2 
2025-07-15 00:00 UT   10 46 04.3   +02 26 42    17.455   16.817   49.8    2.6   116   37.2 
2025-07-16 00:00 UT   10 46 13.3   +02 26 03    17.474   16.823   48.9    2.6   117   37.2 
2025-07-17 00:00 UT   10 46 22.4   +02 25 24    17.493   16.830   48.0    2.6   117   37.2 
2025-07-18 00:00 UT   10 46 31.7   +02 24 43    17.512   16.836   47.0    2.5   117   37.2 
2025-07-19 00:00 UT   10 46 41.0   +02 24 01    17.530   16.843   46.1    2.5   117   37.2 
2025-07-20 00:00 UT   10 46 50.5   +02 23 18    17.549   16.849   45.2    2.5   117   37.2 
2025-07-21 00:00 UT   10 47 00.2   +02 22 34    17.567   16.856   44.3    2.4   117   37.2 
2025-07-22 00:00 UT   10 47 09.9   +02 21 49    17.585   16.862   43.4    2.4   118   37.2 

    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.