C/2020 P4-C (SOHO)
ephemeris	date	magn	radius	delta	ra	dec	elong	phase	PA
Perihelion	5 Aug 2020	7.0	0.090 AU	0.949 AU	09h14m	+19°05'	3.6°	134.9°	52°
Nearest approach	7 Aug 2020	8.6	0.137 AU	0.908 AU	08h48m	+17°05'	5.2°	138.0°	278°
Today	23 Dec 2025	39.5	25.797 AU	25.005 AU	06h11m	-13°48'	142.7°	1.3°	358°

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 18.4 + 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-C (SOHO) are:

    e (Eccentricity)                : 1.0132750
    q (Perihelion distance)         : 0.0896130
    i (Inclination)                 : 37.27090
    Ω (Longitude of ascending node) : 165.25880
    ω (Argument of perihelion)      : 115.99670
    L (Longitude of perihelion)     : 106.75911
    B (Latitude of perihelion)      : 32.97758
    T (Time of perihelion passage)  : 2459066.94100

    Epoch                           : 2025 Dec 22
    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
2025-12-22 00:00 UT   06 11 17.5   -13 48 22    24.991   25.782  142.7    1.3   356   39.5 
2025-12-23 00:00 UT   06 11 07.9   -13 48 19    25.004   25.796  142.7    1.3   357   39.5 
2025-12-23 02:40 UT   06 11 06.8   -13 48 18    25.005   25.797  142.7    1.3   358   39.5 
2025-12-24 00:00 UT   06 10 58.2   -13 48 15    25.017   25.809  142.8    1.3   359   39.5 
2025-12-25 00:00 UT   06 10 48.6   -13 48 09    25.031   25.823  142.8    1.3     1   39.5 
2025-12-26 00:00 UT   06 10 39.0   -13 48 01    25.045   25.837  142.8    1.3     3   39.5 
2025-12-27 00:00 UT   06 10 29.4   -13 47 52    25.059   25.851  142.8    1.3     4   39.5 
2025-12-28 00:00 UT   06 10 19.8   -13 47 42    25.074   25.865  142.7    1.3     6   39.5 
2025-12-29 00:00 UT   06 10 10.3   -13 47 30    25.089   25.879  142.6    1.3     8   39.5 
2025-12-30 00:00 UT   06 10 00.8   -13 47 16    25.104   25.893  142.5    1.3    10   39.5 
2025-12-31 00:00 UT   06 09 51.3   -13 47 01    25.119   25.907  142.4    1.3    11   39.5 
2026-01-01 00:00 UT   06 09 41.8   -13 46 45    25.135   25.921  142.2    1.3    13   39.5 
2026-01-02 00:00 UT   06 09 32.4   -13 46 27    25.151   25.935  142.0    1.3    15   39.5 

    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.