C/1995 O1 (Hale-Bopp)
ephemeris	date	magn	radius	delta	ra	dec	elong	phase	PA
Nearest approach	19 Mar 1997	-1.7	0.939 AU	1.304 AU	00h09m	+45°30'	45.8°	49.5°	4°
Perihelion	29 Mar 1997	-1.7	0.925 AU	1.337 AU	01h38m	+44°28'	43.7°	48.3°	25°
Today	21 Sep 2026	23.6	51.114 AU	51.022 AU	21h49m	-85°24'	94.6°	1.1°	31°

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)                : 0.9948970
    q (Perihelion distance)         : 0.9251900
    i (Inclination)                 : 89.73620
    Ω (Longitude of ascending node) : 281.80430
    ω (Argument of perihelion)      : 130.72450
    L (Longitude of perihelion)     : 281.49787
    B (Latitude of perihelion)      : 49.27479
    T (Time of perihelion passage)  : 2450536.53220
    P (Orbital period in years)     : 2441.23

    Epoch                           : 2026 Sep 20
    Reference                       : MPC194091

    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
2026-09-20 00:00 UT   21 50 56.9   -85 25 47    51.005   51.109   95.3    1.1    29   23.6 
2026-09-21 00:00 UT   21 50 10.0   -85 25 16    51.016   51.112   94.9    1.1    30   23.6 
2026-09-21 15:13 UT   21 49 40.6   -85 24 56    51.022   51.114   94.6    1.1    31   23.6 
2026-09-22 00:00 UT   21 49 23.8   -85 24 44    51.026   51.115   94.5    1.1    32   23.6 
2026-09-23 00:00 UT   21 48 38.4   -85 24 10    51.037   51.118   94.0    1.1    33   23.6 
2026-09-24 00:00 UT   21 47 53.6   -85 23 35    51.048   51.121   93.6    1.1    34   23.6 
2026-09-25 00:00 UT   21 47 09.7   -85 22 59    51.058   51.124   93.2    1.1    35   23.6 
2026-09-26 00:00 UT   21 46 26.5   -85 22 22    51.069   51.127   92.7    1.1    36   23.6 
2026-09-27 00:00 UT   21 45 44.1   -85 21 44    51.080   51.131   92.3    1.1    37   23.6 
2026-09-28 00:00 UT   21 45 02.4   -85 21 05    51.090   51.134   91.9    1.1    38   23.6 
2026-09-29 00:00 UT   21 44 21.6   -85 20 25    51.101   51.137   91.4    1.1    39   23.6 
2026-09-30 00:00 UT   21 43 41.6   -85 19 43    51.112   51.140   91.0    1.1    40   23.6 
2026-10-01 00:00 UT   21 43 02.5   -85 19 01    51.122   51.143   90.6    1.1    41   23.6 

    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.