C/2020 B3 (Rankin)
ephemeris	date	magn	radius	delta	ra	dec	elong	phase	PA
Perihelion	20 Oct 2019	21.2	3.327 AU	3.980 AU	10h47m	-02°52'	43.4°	11.9°	282°
Nearest approach	13 Mar 2020	20.6	3.592 AU	2.616 AU	12h19m	-03°57'	166.9°	3.6°	301°
Today	13 Jul 2025	30.6	15.326 AU	14.416 AU	18h15m	-01°18'	152.5°	1.8°	140°

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 B3 (Rankin) are:

            e (Eccentricity)                : 0.9968390
            q (Perihelion distance)         : 3.3273660
            i (Inclination)                 : 20.70680
            Ω (Longitude of ascending node) : 185.74510
            ω (Argument of perihelion)      : 324.93140
            L (Longitude of perihelion)     : 152.45435
            B (Latitude of perihelion)      : -11.72153
            T (Time of perihelion passage)  : 2458777.29360
            P (Orbital period in years)     : 34151.84

            Epoch                           : 2025 Jul 12
            Reference                       : MPEC 2022-N37

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

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 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. (13.00 + 5 log[∆] + 10.00 log[r]).

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
2025-07-13 00:00 UT   18 15 16.9   -01 18 14    14.412   15.323  152.7    1.7   140   30.6 
2025-07-13 09:48 UT   18 15 11.7   -01 18 27    14.416   15.326  152.5    1.8   140   30.6 
2025-07-14 00:00 UT   18 15 04.4   -01 18 47    14.422   15.329  152.2    1.8   139   30.7 
2025-07-15 00:00 UT   18 14 51.9   -01 19 22    14.433   15.334  151.6    1.8   137   30.7 
2025-07-16 00:00 UT   18 14 39.6   -01 19 58    14.443   15.340  150.9    1.8   135   30.7 
2025-07-17 00:00 UT   18 14 27.4   -01 20 36    14.454   15.345  150.3    1.9   134   30.7 
2025-07-18 00:00 UT   18 14 15.4   -01 21 15    14.465   15.351  149.6    1.9   132   30.7 
2025-07-19 00:00 UT   18 14 03.4   -01 21 55    14.476   15.356  149.0    2.0   131   30.7 
2025-07-20 00:00 UT   18 13 51.6   -01 22 36    14.488   15.362  148.3    2.0   129   30.7 
2025-07-21 00:00 UT   18 13 39.8   -01 23 19    14.500   15.367  147.6    2.0   128   30.7 
2025-07-22 00:00 UT   18 13 28.3   -01 24 03    14.512   15.373  146.8    2.1   127   30.7 
2025-07-23 00:00 UT   18 13 16.8   -01 24 48    14.524   15.378  146.1    2.1   125   30.7 

    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.