381P/LINEAR-Spacewatch
ephemeris	date	magn	radius	delta	ra	dec	elong	phase	PA
Nearest approach	8 Sep 2019	19.9	2.289 AU	1.293 AU	22h33m	+02°07'	168.7°	5.0°	134°
Perihelion	24 Sep 2019	19.9	2.285 AU	1.326 AU	22h32m	-03°20'	157.3°	9.7°	81°
Today	16 Dec 2025	27.8	10.956 AU	10.631 AU	10h19m	-01°52'	106.7°	4.9°	295°

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. (17.5 + 5 log[∆] + 5.0 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 381P/LINEAR-Spacewatch are:

    e (Eccentricity)                : 0.6802410
    q (Perihelion distance)         : 2.2847570
    i (Inclination)                 : 28.32490
    Ω (Longitude of ascending node) : 173.83110
    ω (Argument of perihelion)      : 173.33840
    L (Longitude of perihelion)     : 167.96114
    B (Latitude of perihelion)      : 3.15521
    T (Time of perihelion passage)  : 2458750.60370
    P (Orbital period in years)     : 19.10

    Epoch                           : 2025 Dec 15
    Reference                       : MPEC 2025-W75

    Classification(s):              : Ecliptic; Jupiter family
    Tisserand (Jupiter)             : 2.240

Ephemerides

Date       Time       RA (2000)    DEC (2000)    delta   radius  elong  phase   PA    magn
2025-12-15 00:00 UT   10 20 00.6   -01 52 25    10.656   10.953  105.0    5.0   295   27.8 
2025-12-16 00:00 UT   10 19 56.9   -01 52 43    10.641   10.954  106.1    5.0   295   27.8 
2025-12-16 16:35 UT   10 19 54.2   -01 52 54    10.631   10.956  106.7    4.9   295   27.8 
2025-12-17 00:00 UT   10 19 52.9   -01 52 59    10.627   10.956  107.1    4.9   295   27.8 
2025-12-18 00:00 UT   10 19 48.5   -01 53 12    10.613   10.958  108.1    4.9   295   27.8 
2025-12-19 00:00 UT   10 19 43.8   -01 53 23    10.598   10.960  109.1    4.9   296   27.8 
2025-12-20 00:00 UT   10 19 38.7   -01 53 31    10.584   10.962  110.1    4.8   296   27.8 
2025-12-21 00:00 UT   10 19 33.3   -01 53 37    10.570   10.963  111.1    4.8   296   27.8 
2025-12-22 00:00 UT   10 19 27.5   -01 53 41    10.556   10.965  112.1    4.8   296   27.8 
2025-12-23 00:00 UT   10 19 21.3   -01 53 42    10.543   10.967  113.1    4.7   297   27.8 
2025-12-24 00:00 UT   10 19 14.9   -01 53 41    10.529   10.969  114.2    4.7   297   27.8 
2025-12-25 00:00 UT   10 19 08.1   -01 53 37    10.516   10.970  115.2    4.7   297   27.8 
2025-12-26 00:00 UT   10 19 00.9   -01 53 31    10.502   10.972  116.2    4.6   297   27.8 

    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.