C/2021 Q3 (ATLAS)
ephemeris date magn radius delta ra dec elong phase PA
Nearest approach15 Jan 202218.65.206 AU4.873 AU17h52m+82°27'104.4°10.5°332°
Perihelion26 Jan 202218.65.206 AU4.880 AU18h32m+84°25'103.9°10.6°331°
Today28 Mar 202421.17.594 AU7.142 AU08h12m+15°57'113.3°6.9°101°
C/2021 Q3 (ATLAS)- 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 Q3 (ATLAS) are:

            e (Eccentricity)                : 0.9311810
            q (Perihelion distance)         : 5.2056520
            i (Inclination)                 : 77.74110
            Ω (Longitude of ascending node) : 307.91510
            ω (Argument of perihelion)      : 114.11630
            L (Longitude of perihelion)     : 282.53981
            B (Latitude of perihelion)      : 63.11378
            T (Time of perihelion passage)  : 2459605.80900
            P (Orbital period in years)     : 657.89

            Epoch                           : 2024 Mar 28
            Reference                       : MPEC 2023-FK0

            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. (8.00 + 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
2024-03-28 00:00 UT   08 12 39.4   +15 59 25     7.124    7.589  114.3    6.9   101   21.1 
2024-03-28 21:52 UT   08 12 27.8   +15 57 22     7.142    7.594  113.3    6.9   101   21.1 
2024-03-29 00:00 UT   08 12 26.7   +15 57 10     7.144    7.594  113.3    6.9   101   21.1 
2024-03-30 00:00 UT   08 12 14.5   +15 54 54     7.164    7.599  112.2    7.0   101   21.1 
2024-03-31 00:00 UT   08 12 03.0   +15 52 37     7.185    7.603  111.2    7.0   101   21.1 
2024-04-01 00:00 UT   08 11 52.0   +15 50 19     7.205    7.608  110.2    7.1   101   21.1 
2024-04-02 00:00 UT   08 11 41.7   +15 48 01     7.226    7.613  109.2    7.1   101   21.1 
2024-04-03 00:00 UT   08 11 32.0   +15 45 42     7.246    7.618  108.2    7.2   101   21.1 
2024-04-04 00:00 UT   08 11 22.8   +15 43 22     7.267    7.622  107.1    7.2   101   21.1 
2024-04-05 00:00 UT   08 11 14.3   +15 41 01     7.288    7.627  106.1    7.2   101   21.1 
2024-04-06 00:00 UT   08 11 06.4   +15 38 40     7.309    7.632  105.1    7.3   101   21.1 
2024-04-07 00:00 UT   08 10 59.0   +15 36 18     7.330    7.637  104.1    7.3   101   21.2 


    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.