217P/LINEAR
ephemeris	date	magn	radius	delta	ra	dec	elong	phase	PA
Perihelion	24 May 2025	12.3	1.226 AU	2.008 AU	02h22m	+06°32'	29.1°	23.7°	238°
Today	13 Oct 2025	16.4	2.070 AU	2.183 AU	08h44m	+13°11'	70.2°	27.0°	283°
Nearest approach	2 Jan 2026	18.1	2.722 AU	1.838 AU	09h04m	+15°50'	147.9°	11.1°	288°

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 9.3 + 5 log[∆] + 17.1 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 217P/LINEAR are:

    e (Eccentricity)                : 0.6892210
    q (Perihelion distance)         : 1.2263760
    i (Inclination)                 : 12.86600
    Ω (Longitude of ascending node) : 125.36910
    ω (Argument of perihelion)      : 247.04420
    L (Longitude of perihelion)     : 191.88547
    B (Latitude of perihelion)      : -11.83169
    T (Time of perihelion passage)  : 2460820.45660
    P (Orbital period in years)     : 7.84

    Epoch                           : 2025 Oct 12
    Reference                       : MPEC 2025-T80

    Classification(s):              : Ecliptic; Jupiter family
    Tisserand (Jupiter)             : 2.549

Ephemerides

Date       Time       RA (2000)    DEC (2000)    delta   radius  elong  phase   PA    magn
2025-10-13 00:00 UT   08 43 38.2   +13 13 01     2.185    2.066   69.9   27.0   283   16.4 
2025-10-13 12:32 UT   08 44 19.4   +13 11 32     2.183    2.070   70.2   27.0   283   16.4 
2025-10-14 00:00 UT   08 44 56.8   +13 10 11     2.181    2.074   70.5   27.0   284   16.4 
2025-10-15 00:00 UT   08 46 14.1   +13 07 23     2.178    2.082   71.2   27.0   284   16.4 
2025-10-16 00:00 UT   08 47 29.9   +13 04 40     2.174    2.091   71.9   27.0   284   16.5 
2025-10-17 00:00 UT   08 48 44.5   +13 01 60     2.170    2.099   72.6   26.9   284   16.5 
2025-10-18 00:00 UT   08 49 57.7   +12 59 24     2.166    2.107   73.2   26.9   284   16.5 
2025-10-19 00:00 UT   08 51 09.5   +12 56 52     2.162    2.115   73.9   26.9   284   16.5 
2025-10-20 00:00 UT   08 52 19.9   +12 54 25     2.158    2.124   74.6   26.9   285   16.6 
2025-10-21 00:00 UT   08 53 28.9   +12 52 02     2.153    2.132   75.4   26.9   285   16.6 
2025-10-22 00:00 UT   08 54 36.6   +12 49 44     2.149    2.140   76.1   26.8   285   16.6 
2025-10-23 00:00 UT   08 55 42.8   +12 47 31     2.145    2.148   76.8   26.8   285   16.6 

    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.