C/2021 C1 (Rankin)
ephemeris date magn radius delta ra dec elong phase PA
Perihelion6 Dec 202020.03.475 AU4.179 AU14h00m-24°43'39.4°10.4°276°
Nearest approach24 Mar 202119.23.612 AU2.620 AU12h33m-04°49'173.6°1.7°303°
Today28 Mar 202426.610.128 AU10.097 AU06h43m+60°04'88.9°5.7°95°
C/2021 C1 (Rankin)- 2024-03-28
astro.vanbuitenen.nl


 
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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/2021 C1 (Rankin) are:

            e (Eccentricity)                : 0.9989900
            q (Perihelion distance)         : 3.4745450
            i (Inclination)                 : 143.04320
            Ω (Longitude of ascending node) : 186.87900
            ω (Argument of perihelion)      : 336.15770
            L (Longitude of perihelion)     : 206.32943
            B (Latitude of perihelion)      : -14.06501
            T (Time of perihelion passage)  : 2459190.09720
            P (Orbital period in years)     : 201773.84

            Epoch                           : 2024 Mar 27
            Reference                       : MPEC 2023-KD6

            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. (11.50 + 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
2024-03-28 00:00 UT   06 43 14.5   +60 06 33    10.085   10.124   89.4    5.7    95   26.6 
2024-03-28 13:18 UT   06 43 07.3   +60 04 40    10.097   10.128   88.9    5.7    95   26.6 
2024-03-29 00:00 UT   06 43 01.7   +60 03 10    10.106   10.131   88.6    5.7    94   26.6 
2024-03-30 00:00 UT   06 42 49.8   +59 59 47    10.126   10.137   87.8    5.6    94   26.6 
2024-03-31 00:00 UT   06 42 38.7   +59 56 24    10.146   10.143   87.0    5.6    93   26.6 
2024-04-01 00:00 UT   06 42 28.5   +59 53 02    10.167   10.149   86.2    5.6    92   26.6 
2024-04-02 00:00 UT   06 42 19.2   +59 49 40    10.187   10.155   85.3    5.6    92   26.6 
2024-04-03 00:00 UT   06 42 10.7   +59 46 19    10.207   10.162   84.5    5.6    91   26.6 
2024-04-04 00:00 UT   06 42 03.1   +59 42 59    10.228   10.168   83.7    5.6    91   26.6 
2024-04-05 00:00 UT   06 41 56.4   +59 39 39    10.248   10.174   82.9    5.6    90   26.6 
2024-04-06 00:00 UT   06 41 50.4   +59 36 20    10.268   10.180   82.1    5.6    89   26.6 
2024-04-07 00:00 UT   06 41 45.3   +59 33 02    10.289   10.186   81.3    5.6    89   26.6 


    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.