P/2021 Q5 (ATLAS)
ephemeris	date	magn	radius	delta	ra	dec	elong	phase	PA
Today	7 Jul 2026	20.1	3.701 AU	2.697 AU	18h48m	-12°45'	169.3°	2.9°	157°
Perihelion	14 Aug 2027	14.4	1.235 AU	1.720 AU	06h26m	+23°09'	45.1°	35.5°	273°
Nearest approach	12 Feb 2028	16.7	2.307 AU	1.447 AU	11h22m	-14°19'	142.1°	15.2°	317°

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 12.3 + 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 P/2021 Q5 (ATLAS) are:

    e (Eccentricity)                : 0.6241030
    q (Perihelion distance)         : 1.2345090
    i (Inclination)                 : 10.73620
    Ω (Longitude of ascending node) : 239.72520
    ω (Argument of perihelion)      : 180.97750
    L (Longitude of perihelion)     : 240.68559
    B (Latitude of perihelion)      : -0.18209
    T (Time of perihelion passage)  : 2461632.15150
    P (Orbital period in years)     : 5.95

    Epoch                           : 2026 Jul 07
    Reference                       : MPC194176

    Classification(s):              : Ecliptic; Jupiter family
    Tisserand (Jupiter)             : 2.804

Ephemerides

Date       Time       RA (2000)    DEC (2000)    delta   radius  elong  phase   PA    magn
2026-07-06 00:00 UT   18 50 18.0   -12 45 33     2.705    3.710  169.8    2.8   168   20.2 
2026-07-07 00:00 UT   18 49 23.2   -12 45 22     2.700    3.705  169.6    2.8   162   20.1 
2026-07-07 19:43 UT   18 48 38.1   -12 45 15     2.697    3.701  169.3    2.9   157   20.1 
2026-07-08 00:00 UT   18 48 28.3   -12 45 13     2.696    3.700  169.2    2.9   156   20.1 
2026-07-09 00:00 UT   18 47 33.4   -12 45 08     2.692    3.695  168.8    3.1   150   20.1 
2026-07-10 00:00 UT   18 46 38.5   -12 45 06     2.688    3.689  168.2    3.2   145   20.1 
2026-07-11 00:00 UT   18 45 43.5   -12 45 06     2.685    3.684  167.6    3.4   141   20.1 
2026-07-12 00:00 UT   18 44 48.6   -12 45 10     2.682    3.679  166.9    3.6   136   20.1 
2026-07-13 00:00 UT   18 43 53.9   -12 45 16     2.679    3.674  166.1    3.8   133   20.1 
2026-07-14 00:00 UT   18 42 59.2   -12 45 26     2.676    3.669  165.3    4.0   129   20.1 
2026-07-15 00:00 UT   18 42 04.8   -12 45 38     2.674    3.663  164.4    4.3   126   20.1 
2026-07-16 00:00 UT   18 41 10.6   -12 45 53     2.672    3.658  163.5    4.5   124   20.1 
2026-07-17 00:00 UT   18 40 16.7   -12 46 10     2.671    3.653  162.6    4.8   121   20.1 

    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.