490P/ATLAS
ephemeris	date	magn	radius	delta	ra	dec	elong	phase	PA
Perihelion	28 Sep 2024	22.0	1.070 AU	1.394 AU	15h25m	-23°09'	49.8°	45.7°	108°
Nearest approach	11 Oct 2024	22.1	1.085 AU	1.378 AU	16h31m	-23°54'	51.3°	45.9°	100°
Today	22 Oct 2025	28.9	3.637 AU	2.891 AU	04h47m	+36°28'	132.3°	11.7°	250°

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. 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. (21.0 + 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 490P/ATLAS are:

    e (Eccentricity)                : 0.6470200
    q (Perihelion distance)         : 1.0697060
    i (Inclination)                 : 12.26710
    Ω (Longitude of ascending node) : 307.59060
    ω (Argument of perihelion)      : 332.57430
    L (Longitude of perihelion)     : 280.70232
    B (Latitude of perihelion)      : -5.61612
    T (Time of perihelion passage)  : 2460581.63160
    P (Orbital period in years)     : 5.28

    Epoch                           : 2025 Oct 21
    Reference                       : MPEC 2024-YC7

    Classification(s):              : Ecliptic; Jupiter family
    Tisserand (Jupiter)             : 2.854

Ephemerides

Date       Time       RA (2000)    DEC (2000)    delta   radius  elong  phase   PA    magn
2025-10-21 00:00 UT   04 48 41.8   +36 26 52     2.900    3.629  130.7   12.0   250   28.9 
2025-10-22 00:00 UT   04 48 00.2   +36 28 04     2.894    3.634  131.7   11.8   250   28.9 
2025-10-22 13:05 UT   04 47 37.0   +36 28 41     2.891    3.637  132.3   11.7   250   28.9 
2025-10-23 00:00 UT   04 47 17.3   +36 29 10     2.889    3.639  132.8   11.6   249   28.9 
2025-10-24 00:00 UT   04 46 33.0   +36 30 10     2.883    3.644  133.9   11.3   249   28.9 
2025-10-25 00:00 UT   04 45 47.3   +36 31 04     2.878    3.649  135.0   11.1   248   28.9 
2025-10-26 00:00 UT   04 45 00.3   +36 31 51     2.873    3.654  136.0   10.9   247   28.9 
2025-10-27 00:00 UT   04 44 11.9   +36 32 32     2.868    3.659  137.1   10.7   247   28.9 
2025-10-28 00:00 UT   04 43 22.4   +36 33 05     2.863    3.664  138.2   10.4   246   28.9 
2025-10-29 00:00 UT   04 42 31.5   +36 33 32     2.858    3.669  139.3   10.2   245   28.9 
2025-10-30 00:00 UT   04 41 39.5   +36 33 51     2.854    3.674  140.4    9.9   244   28.9 
2025-10-31 00:00 UT   04 40 46.3   +36 34 04     2.850    3.679  141.4    9.7   243   28.9 
2025-11-01 00:00 UT   04 39 52.0   +36 34 08     2.847    3.684  142.5    9.4   243   28.9 

    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.