C/2020 B3 (Rankin)
ephemeris	date	magn	radius	delta	ra	dec	elong	phase	PA
Perihelion	21 Oct 2019	21.2	3.327 AU	3.973 AU	10h47m	-02°55'	43.8°	12.0°	282°
Nearest approach	13 Mar 2020	20.6	3.589 AU	2.614 AU	12h18m	-03°56'	167.0°	3.6°	301°
Today	13 Apr 2026	31.4	16.802 AU	16.583 AU	18h43m	-02°01'	100.9°	3.4°	261°

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. The light curve is based on the absolute magnitude and slope parameter as calculated from an MPEC, or the latest values provided by the minor planet center. (13.0 + 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 B3 (Rankin) are:

    e (Eccentricity)                : 0.9971110
    q (Perihelion distance)         : 3.3271120
    i (Inclination)                 : 20.70700
    Ω (Longitude of ascending node) : 185.69270
    ω (Argument of perihelion)      : 324.99340
    L (Longitude of perihelion)     : 152.46248
    B (Latitude of perihelion)      : -11.70330
    T (Time of perihelion passage)  : 2458777.90180
    P (Orbital period in years)     : 39082.27

    Epoch                           : 2026 Mar 16
    Reference                       : MPEC 2026-E44

    Classification(s):              : Nearly isotropic; Returning (a < 10000 AU); External (P > 200 years)

Ephemerides

Date       Time       RA (2000)    DEC (2000)    delta   radius  elong  phase   PA    magn
2026-04-12 00:00 UT   18 43 53.5   -02 03 13    16.601   16.793   99.3    3.4   262   31.4 
2026-04-13 00:00 UT   18 43 52.7   -02 01 60    16.590   16.798  100.2    3.4   261   31.4 
2026-04-13 18:01 UT   18 43 51.9   -02 01 05    16.583   16.802  100.9    3.4   261   31.4 
2026-04-14 00:00 UT   18 43 51.6   -02 00 47    16.580   16.803  101.1    3.4   261   31.4 
2026-04-15 00:00 UT   18 43 50.3   -01 59 35    16.570   16.808  102.1    3.3   261   31.4 
2026-04-16 00:00 UT   18 43 48.8   -01 58 24    16.560   16.814  103.0    3.3   260   31.4 
2026-04-17 00:00 UT   18 43 47.0   -01 57 13    16.549   16.819  103.9    3.3   260   31.4 
2026-04-18 00:00 UT   18 43 45.0   -01 56 02    16.539   16.824  104.8    3.3   260   31.4 
2026-04-19 00:00 UT   18 43 42.7   -01 54 52    16.529   16.830  105.7    3.3   259   31.4 
2026-04-20 00:00 UT   18 43 40.2   -01 53 43    16.519   16.835  106.6    3.3   259   31.4 
2026-04-21 00:00 UT   18 43 37.5   -01 52 34    16.510   16.840  107.5    3.3   258   31.4 
2026-04-22 00:00 UT   18 43 34.6   -01 51 26    16.500   16.846  108.5    3.2   258   31.4 
2026-04-23 00:00 UT   18 43 31.4   -01 50 18    16.490   16.851  109.4    3.2   258   31.4 

    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.