28P/Neujmin
ephemeris	date	magn	radius	delta	ra	dec	elong	phase	PA
Perihelion	9 Mar 2021	16.0	1.588 AU	2.560 AU	22h48m	-09°38'	9.2°	5.7°	236°
Nearest approach	7 Nov 2021	17.0	3.060 AU	2.239 AU	05h13m	+42°39'	139.5°	12.2°	241°
Today	31 Dec 2025	22.6	10.340 AU	9.565 AU	09h34m	+23°00'	140.3°	3.5°	279°

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 13.1 + 5 log[∆] + 4.5 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 28P/Neujmin are:

    e (Eccentricity)                : 0.7724810
    q (Perihelion distance)         : 1.5877990
    i (Inclination)                 : 14.28870
    Ω (Longitude of ascending node) : 346.42220
    ω (Argument of perihelion)      : 347.42880
    L (Longitude of perihelion)     : 334.22808
    B (Latitude of perihelion)      : -3.07932
    T (Time of perihelion passage)  : 2459282.98450
    P (Orbital period in years)     : 18.44

    Epoch                           : 2025 Dec 30
    Reference                       : MPEC 2025-W75

    Classification(s):              : Ecliptic; Jupiter family
    Tisserand (Jupiter)             : 2.171

Ephemerides

Date       Time       RA (2000)    DEC (2000)    delta   radius  elong  phase   PA    magn
2025-12-30 00:00 UT   09 35 10.4   +22 58 43     9.576   10.337  138.9    3.6   279   22.6 
2025-12-31 00:00 UT   09 34 54.8   +23 00 18     9.568   10.340  139.9    3.5   279   22.6 
2025-12-31 07:29 UT   09 34 49.9   +23 00 48     9.565   10.340  140.3    3.5   279   22.6 
2026-01-01 00:00 UT   09 34 38.9   +23 01 54     9.559   10.342  141.0    3.4   279   22.6 
2026-01-02 00:00 UT   09 34 22.7   +23 03 31     9.552   10.345  142.0    3.4   278   22.6 
2026-01-03 00:00 UT   09 34 06.1   +23 05 08     9.544   10.347  143.1    3.3   278   22.6 
2026-01-04 00:00 UT   09 33 49.3   +23 06 46     9.537   10.350  144.2    3.2   277   22.6 
2026-01-05 00:00 UT   09 33 32.1   +23 08 25     9.530   10.353  145.2    3.1   277   22.6 
2026-01-06 00:00 UT   09 33 14.6   +23 10 04     9.523   10.355  146.3    3.0   276   22.6 
2026-01-07 00:00 UT   09 32 56.8   +23 11 43     9.517   10.358  147.3    2.9   276   22.6 
2026-01-08 00:00 UT   09 32 38.7   +23 13 23     9.510   10.361  148.4    2.9   275   22.6 
2026-01-09 00:00 UT   09 32 20.4   +23 15 03     9.504   10.363  149.4    2.8   275   22.6 
2026-01-10 00:00 UT   09 32 01.8   +23 16 43     9.499   10.366  150.5    2.7   274   22.6 

    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.