C/2021 X1 (Maury-Attard)
ephemeris	date	magn	radius	delta	ra	dec	elong	phase	PA
Perihelion	27 May 2023	15.3	3.234 AU	4.079 AU	02h42m	+02°34'	29.3°	8.8°	229°
Nearest approach	25 Sep 2023	14.6	3.432 AU	2.441 AU	00h39m	+06°40'	169.6°	3.0°	235°
Today	21 Sep 2026	24.1	10.252 AU	10.070 AU	18h26m	+17°24'	97.6°	5.6°	93°

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 5.4 + 5 log[∆] + 13.6 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/2021 X1 (Maury-Attard) are:

    e (Eccentricity)                : 1.0009540
    q (Perihelion distance)         : 3.2338380
    i (Inclination)                 : 140.11270
    Ω (Longitude of ascending node) : 10.66250
    ω (Argument of perihelion)      : 334.65600
    L (Longitude of perihelion)     : 30.63494
    B (Latitude of perihelion)      : -15.93228
    T (Time of perihelion passage)  : 2460092.05210

    Epoch                           : 2026 Sep 20
    Reference                       : MPC194178

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

Ephemerides

Date       Time       RA (2000)    DEC (2000)    delta   radius  elong  phase   PA    magn
2026-09-20 00:00 UT   18 26 35.1   +17 30 23    10.040   10.243   98.8    5.6    94   24.1 
2026-09-21 00:00 UT   18 26 26.5   +17 26 25    10.059   10.249   98.1    5.6    94   24.1 
2026-09-21 13:22 UT   18 26 21.9   +17 24 13    10.070   10.252   97.6    5.6    93   24.1 
2026-09-22 00:00 UT   18 26 18.4   +17 22 29    10.079   10.255   97.3    5.6    93   24.1 
2026-09-23 00:00 UT   18 26 10.7   +17 18 32    10.098   10.261   96.5    5.6    92   24.1 
2026-09-24 00:00 UT   18 26 03.4   +17 14 37    10.118   10.268   95.8    5.6    92   24.1 
2026-09-25 00:00 UT   18 25 56.6   +17 10 42    10.138   10.274   95.0    5.6    91   24.1 
2026-09-26 00:00 UT   18 25 50.3   +17 06 47    10.157   10.280   94.2    5.6    90   24.1 
2026-09-27 00:00 UT   18 25 44.3   +17 02 54    10.177   10.287   93.5    5.6    90   24.1 
2026-09-28 00:00 UT   18 25 38.9   +16 59 02    10.197   10.293   92.7    5.6    89   24.2 
2026-09-29 00:00 UT   18 25 33.8   +16 55 11    10.216   10.299   91.9    5.6    88   24.2 
2026-09-30 00:00 UT   18 25 29.2   +16 51 20    10.236   10.305   91.1    5.6    88   24.2 
2026-10-01 00:00 UT   18 25 25.0   +16 47 31    10.256   10.312   90.4    5.6    87   24.2 

    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.