C/2026 M3 (MASTER)
ephemeris	date	magn	radius	delta	ra	dec	elong	phase	PA
Nearest approach	30 Jun 2026	20.0	12.123 AU	11.405 AU	18h25m	+23°39'	133.1°	3.5°	176°
Today	17 Jul 2026	20.0	12.117 AU	11.437 AU	18h19m	+23°59'	130.1°	3.7°	153°
Perihelion	30 Dec 2026	20.3	12.089 AU	12.750 AU	18h23m	+22°47'	46.1°	3.4°	356°

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. (3.9 + 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 C/2026 M3 (MASTER) are:

    e (Eccentricity)                : 1.0110190
    q (Perihelion distance)         : 12.0886060
    i (Inclination)                 : 94.05500
    Ω (Longitude of ascending node) : 282.51910
    ω (Argument of perihelion)      : 49.59770
    L (Longitude of perihelion)     : 277.76976
    B (Latitude of perihelion)      : 49.42947
    T (Time of perihelion passage)  : 2461405.11460

    Epoch                           : 2026 Jul 16
    Reference                       : MPEC 2026-O09

    Classification(s):              : Nearly isotropic; New (a > 10000 AU)

Ephemerides

Date       Time       RA (2000)    DEC (2000)    delta   radius  elong  phase   PA    magn
2026-07-16 00:00 UT   18 19 56.4   +23 58 30    11.431   12.117  130.6    3.7   155   20.0 
2026-07-17 00:00 UT   18 19 33.8   +23 59 14    11.435   12.117  130.3    3.7   154   20.0 
2026-07-17 13:45 UT   18 19 20.9   +23 59 37    11.437   12.117  130.1    3.7   153   20.0 
2026-07-18 00:00 UT   18 19 11.3   +23 59 54    11.439   12.117  130.0    3.7   153   20.0 
2026-07-19 00:00 UT   18 18 49.0   +24 00 30    11.443   12.116  129.7    3.7   151   20.0 
2026-07-20 00:00 UT   18 18 26.8   +24 01 03    11.447   12.116  129.3    3.7   150   20.0 
2026-07-21 00:00 UT   18 18 04.8   +24 01 31    11.451   12.116  129.0    3.7   149   20.0 
2026-07-22 00:00 UT   18 17 42.9   +24 01 56    11.455   12.115  128.6    3.8   148   20.0 
2026-07-23 00:00 UT   18 17 21.3   +24 02 18    11.460   12.115  128.2    3.8   146   20.0 
2026-07-24 00:00 UT   18 16 59.8   +24 02 36    11.465   12.115  127.8    3.8   145   20.0 
2026-07-25 00:00 UT   18 16 38.5   +24 02 50    11.470   12.114  127.4    3.8   144   20.0 
2026-07-26 00:00 UT   18 16 17.4   +24 03 01    11.475   12.114  127.0    3.8   143   20.0 
2026-07-27 00:00 UT   18 15 56.5   +24 03 09    11.481   12.114  126.6    3.9   142   20.0 

    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.