C/1995 O1 (Hale-Bopp)
ephemeris	date	magn	radius	delta	ra	dec	elong	phase	PA
Nearest approach	21 Mar 1997	-1.8	0.926 AU	1.305 AU	00h11m	+45°16'	45.0°	49.5°	3°
Perihelion	30 Mar 1997	-1.8	0.912 AU	1.339 AU	01h41m	+44°16'	42.9°	48.2°	24°
Today	15 Dec 2025	23.5	50.230 AU	50.648 AU	21h44m	-84°18'	64.3°	1.0°	114°

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. (-2.0 + 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/1995 O1 (Hale-Bopp) are:

    e (Eccentricity)                : 0.9949270
    q (Perihelion distance)         : 0.9115400
    i (Inclination)                 : 89.63710
    Ω (Longitude of ascending node) : 281.94960
    ω (Argument of perihelion)      : 130.40830
    L (Longitude of perihelion)     : 281.52333
    B (Latitude of perihelion)      : 49.59035
    T (Time of perihelion passage)  : 2450537.93470
    P (Orbital period in years)     : 2408.61

    Epoch                           : 2025 Dec 14
    Reference                       : MPEC 2022-S20

    Classification(s):              : Nearly isotropic; Returning (a < 10000 AU); External (P > 200 years)

Ephemerides

Date       Time       RA (2000)    DEC (2000)    delta   radius  elong  phase   PA    magn
2025-12-14 00:00 UT   21 44 21.8   -84 20 19    50.641   50.226   64.5    1.0   113   23.5 
2025-12-15 00:00 UT   21 44 42.9   -84 19 15    50.646   50.229   64.4    1.0   114   23.5 
2025-12-15 07:48 UT   21 44 49.9   -84 18 55    50.648   50.230   64.3    1.0   114   23.5 
2025-12-16 00:00 UT   21 45 04.6   -84 18 12    50.652   50.232   64.2    1.0   115   23.5 
2025-12-17 00:00 UT   21 45 26.9   -84 17 09    50.657   50.236   64.1    1.0   116   23.5 
2025-12-18 00:00 UT   21 45 49.7   -84 16 06    50.662   50.239   63.9    1.0   117   23.5 
2025-12-19 00:00 UT   21 46 13.0   -84 15 04    50.667   50.242   63.8    1.0   118   23.5 
2025-12-20 00:00 UT   21 46 36.8   -84 14 03    50.672   50.245   63.7    1.0   119   23.5 
2025-12-21 00:00 UT   21 47 01.1   -84 13 02    50.677   50.248   63.6    1.0   120   23.5 
2025-12-22 00:00 UT   21 47 25.9   -84 12 01    50.682   50.251   63.5    1.0   121   23.5 
2025-12-23 00:00 UT   21 47 51.2   -84 11 01    50.686   50.254   63.4    1.0   122   23.5 
2025-12-24 00:00 UT   21 48 17.0   -84 10 01    50.691   50.258   63.3    1.0   123   23.5 
2025-12-25 00:00 UT   21 48 43.2   -84 09 02    50.695   50.261   63.2    1.0   124   23.5 

    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.