C/2020 S4 (PANSTARRS)
ephemeris date magn radius delta ra dec elong phase PA
Nearest approach6 Feb 202315.13.373 AU2.397 AU 09h29m+25°12'170.1°2.9°198°
Perihelion9 Feb 202315.13.373 AU2.399 AU 09h28m+25°42'168.9°3.2°176°
Today27 Jun 202625.510.347 AU9.470 AU 16h36m-05°07'148.0°3.0°127°
C/2020 S4 (PANSTARRS)- 2026-06-27
astro.vanbuitenen.nl


 
-1 month
-1 week
-1 day
Now
+1 day
+1 week
+1 month

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 5.1 + 5 log[∆] + 15.3 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 S4 (PANSTARRS) are:

    e (Eccentricity)                : 1.0033170
    q (Perihelion distance)         : 3.3727090
    i (Inclination)                 : 20.57190
    Ω (Longitude of ascending node) : 117.67490
    ω (Argument of perihelion)      : 21.11720
    L (Longitude of perihelion)     : 137.55412
    B (Latitude of perihelion)      : 7.27287
    T (Time of perihelion passage)  : 2459985.39040

    Epoch                           : 2026 Jun 27
    Reference                       : MPC194170

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

Ephemerides

Date       Time       RA (2000)    DEC (2000)    delta   radius  elong  phase   PA    magn
2026-06-26 00:00 UT   16 36 48.0   -05 06 02     9.445   10.335  149.6    2.9   129   25.4 
2026-06-27 00:00 UT   16 36 31.8   -05 06 39     9.459   10.341  148.7    2.9   128   25.5 
2026-06-27 20:22 UT   16 36 18.3   -05 07 11     9.470   10.347  148.0    3.0   127   25.5 
2026-06-28 00:00 UT   16 36 15.9   -05 07 17     9.472   10.348  147.9    3.0   127   25.5 
2026-06-29 00:00 UT   16 36 00.1   -05 07 58     9.486   10.354  147.1    3.1   126   25.5 
2026-06-30 00:00 UT   16 35 44.6   -05 08 40     9.500   10.360  146.2    3.1   125   25.5 
2026-07-01 00:00 UT   16 35 29.3   -05 09 24     9.514   10.366  145.3    3.2   124   25.5 
2026-07-02 00:00 UT   16 35 14.3   -05 10 09     9.528   10.373  144.5    3.3   123   25.5 
2026-07-03 00:00 UT   16 34 59.5   -05 10 57     9.543   10.379  143.6    3.3   123   25.5 
2026-07-04 00:00 UT   16 34 44.9   -05 11 46     9.558   10.385  142.7    3.4   122   25.5 
2026-07-05 00:00 UT   16 34 30.6   -05 12 37     9.573   10.391  141.8    3.5   121   25.5 
2026-07-06 00:00 UT   16 34 16.6   -05 13 30     9.588   10.397  140.9    3.5   120   25.5 
2026-07-07 00:00 UT   16 34 02.8   -05 14 25     9.604   10.404  140.0    3.6   119   25.5 



    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.