C/2025 D1 (Groeller)
ephemeris	date	magn	radius	delta	ra	dec	elong	phase	PA
Today	9 May 2025	18.9	14.994 AU	15.157 AU	09h03m	+39°29'	78.8°	3.8°	103°
Nearest approach	3 Feb 2028	18.3	14.128 AU	13.144 AU	08h58m	+13°41'	176.6°	0.2°	31°
Perihelion	19 May 2028	18.5	14.119 AU	14.422 AU	08h41m	+12°19'	70.6°	3.9°	107°

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.)

The orbital elements of C/2025 D1 (Groeller) are:

            e (Eccentricity)                : 1.0029480
            q (Perihelion distance)         : 14.1191430
            i (Inclination)                 : 84.46640
            Ω (Longitude of ascending node) : 312.89780
            ω (Argument of perihelion)      : 185.88850
            L (Longitude of perihelion)     : 313.46761
            B (Latitude of perihelion)      : -5.86096
            T (Time of perihelion passage)  : 2461911.40520

            Epoch                           : 2025 May 08
            Reference                       : MPEC 2025-J72

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

The light curve chart below shows the estimated development of the comet's magnitude. Blue and black dots are visual and photometric CCD observations respectively from COBS or the MPC. 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. (1.20 + 5 log[∆] + 10.00 log[r]).

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.
A more printer-friendly version of the same chart can be found further down this page as well.

The following chart shows the current location of the comet in a smaller, upside-down telescopic field of view.

A printable version of the short-term path of the comet in a field of view that is optimized for (~10x50) binoculars and finderscopes.

Ephemerides:

Date       Time       RA (2000)    DEC (2000)    delta   radius  elong  phase   PA    magn
2025-05-09 00:00 UT   09 03 26.9   +39 30 18    15.152   14.995   79.1    3.8   104   18.9 
2025-05-09 08:59 UT   09 03 26.9   +39 29 13    15.157   14.994   78.8    3.8   103   18.9 
2025-05-10 00:00 UT   09 03 27.0   +39 27 23    15.166   14.993   78.3    3.8   103   18.9 
2025-05-11 00:00 UT   09 03 27.5   +39 24 27    15.180   14.992   77.4    3.8   103   18.9 
2025-05-12 00:00 UT   09 03 28.3   +39 21 31    15.194   14.990   76.5    3.8   102   18.9 
2025-05-13 00:00 UT   09 03 29.4   +39 18 34    15.208   14.989   75.6    3.7   102   18.9 
2025-05-14 00:00 UT   09 03 30.8   +39 15 36    15.221   14.987   74.7    3.7   102   18.9 
2025-05-15 00:00 UT   09 03 32.5   +39 12 39    15.235   14.986   73.9    3.7   101   18.9 
2025-05-16 00:00 UT   09 03 34.5   +39 09 40    15.249   14.984   73.0    3.7   101   18.9 
2025-05-17 00:00 UT   09 03 36.8   +39 06 42    15.262   14.983   72.1    3.7   101   18.9 
2025-05-18 00:00 UT   09 03 39.5   +39 03 43    15.276   14.981   71.2    3.7   100   18.9 
2025-05-19 00:00 UT   09 03 42.4   +39 00 44    15.289   14.980   70.4    3.6   100   18.9 

    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.