(404) Arsinoe
ephemeris	date	magn	radius	delta	ra	dec	elong	phase
Today	18 Jul 2025	13.7	2.729 AU	1.982 AU	23h32m	-20°44'	128.1°	17.0°
Opposition	30 Aug 2025	13.2	2.812 AU	1.841 AU	23h09m	-27°00'	160.2°	7.0°

The interactive orbit chart above shows the body'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 Arsinoe are:

            e (Eccentricity)                : 0.2015119
            a (Semimajor axis)              : 2.5923356
            i (Inclination)                 : 14.09831
            Ω (Longitude of ascending node) : 92.46876
            ω (Argument of perihelion)      : 120.55674
            M (Mean anomaly)                : 76.59024
            Epoch                           : 2025 May 05

            L (Longitude of perihelion)     : 33.79825
            B (Latitude of perihelion)      : 12.10821
            P (Orbital period in years)     : 4.17            
        

The light curve chart below shows the estimated development of the minor planet's magnitude.

The all-sky chart below shows the path of the minor planet over the same period as the light curve. The current position is marked yellow.

The following chart shows the path of the minor planet in the next few days. The field of view is optimized for (~10x50) binoculars and finderscopes. A more printer-friendly version of the same chart can be found below.

Ephemerides:

Date       Time       RA (2000)    DEC (2000)    delta   radius  elong  phase   PA    magn
2025-07-18 00:00 UT   23 32 26.7   -20 44 24     1.982    2.729  128.1   17.0   259   13.7 
2025-07-18 22:50 UT   23 32 25.0   -20 51 53     1.975    2.731  129.0   16.8   259   13.7 
2025-07-19 00:00 UT   23 32 24.9   -20 52 16     1.975    2.731  129.0   16.8   259   13.7 
2025-07-20 00:00 UT   23 32 21.4   -21 00 16     1.967    2.733  129.9   16.6   260   13.6 
2025-07-21 00:00 UT   23 32 16.4   -21 08 23     1.960    2.735  130.9   16.3   261   13.6 
2025-07-22 00:00 UT   23 32 09.7   -21 16 37     1.953    2.737  131.8   16.1   261   13.6 
2025-07-23 00:00 UT   23 32 01.5   -21 24 58     1.946    2.739  132.7   15.8   262   13.6 
2025-07-24 00:00 UT   23 31 51.7   -21 33 25     1.939    2.741  133.7   15.5   263   13.6 
2025-07-25 00:00 UT   23 31 40.2   -21 41 59     1.933    2.743  134.6   15.3   263   13.6 
2025-07-26 00:00 UT   23 31 27.2   -21 50 39     1.926    2.745  135.5   15.0   264   13.6 
2025-07-27 00:00 UT   23 31 12.6   -21 59 24     1.920    2.747  136.5   14.8   265   13.5 
2025-07-28 00:00 UT   23 30 56.5   -22 08 14     1.914    2.749  137.4   14.5   266   13.5 
2025-07-29 00:00 UT   23 30 38.7   -22 17 09     1.908    2.751  138.3   14.2   266   13.5 
2025-07-30 00:00 UT   23 30 19.4   -22 26 09     1.903    2.753  139.3   13.9   267   13.5 
2025-07-31 00:00 UT   23 29 58.6   -22 35 12     1.897    2.755  140.2   13.6   268   13.5 
2025-08-01 00:00 UT   23 29 36.2   -22 44 19     1.892    2.757  141.1   13.4   269   13.5 
2025-08-02 00:00 UT   23 29 12.3   -22 53 28     1.887    2.759  142.1   13.1   270   13.5 
2025-08-03 00:00 UT   23 28 46.9   -23 02 41     1.882    2.760  143.0   12.8   271   13.4 
2025-08-04 00:00 UT   23 28 20.0   -23 11 55     1.877    2.762  143.9   12.5   272   13.4 
2025-08-05 00:00 UT   23 27 51.7   -23 21 11     1.873    2.764  144.8   12.2   273   13.4 
2025-08-06 00:00 UT   23 27 21.9   -23 30 28     1.869    2.766  145.7   11.9   275   13.4 
2025-08-07 00:00 UT   23 26 50.6   -23 39 46     1.865    2.768  146.6   11.6   276   13.4 
2025-08-08 00:00 UT   23 26 18.0   -23 49 04     1.861    2.770  147.5   11.3   277   13.4 
2025-08-09 00:00 UT   23 25 44.0   -23 58 21     1.857    2.772  148.4   11.1   279   13.4 
2025-08-10 00:00 UT   23 25 08.6   -24 07 38     1.854    2.774  149.2   10.8   280   13.3 
2025-08-11 00:00 UT   23 24 31.9   -24 16 54     1.851    2.776  150.1   10.5   282   13.3 
2025-08-12 00:00 UT   23 23 53.9   -24 26 08     1.848    2.778  150.9   10.2   283   13.3 
2025-08-13 00:00 UT   23 23 14.6   -24 35 19     1.845    2.779  151.7    9.9   285   13.3 
2025-08-14 00:00 UT   23 22 34.1   -24 44 28     1.843    2.781  152.5    9.7   287   13.3 
2025-08-15 00:00 UT   23 21 52.4   -24 53 33     1.841    2.783  153.3    9.4   289   13.3 
2025-08-16 00:00 UT   23 21 09.5   -25 02 34     1.839    2.785  154.0    9.2   291   13.3 
2025-08-17 00:00 UT   23 20 25.5   -25 11 31     1.837    2.787  154.8    8.9   293   13.3 

    Terminology:
            
    delta:  distance between minor planet and earth in AU
    radius: distance between minor planet 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-minor planet)    
    phase:  phase angle in degrees (angle sun-minor planet-earth)        
    AU:     Astronomical Unit (mean distance between earth and sun: 149597870.7 km
    

Orbital elements provided by 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.