C/2017 E1 (Borisov)
ephemeris	date	magn	radius	delta	ra	dec	elong	phase	PA
Nearest approach	18 Mar 2017	11.5	0.995 AU	1.331 AU	20h42m	-08°22'	48.0°	48.1°	263°
Perihelion	10 Apr 2017	10.8	0.908 AU	1.417 AU	22h43m	-03°31'	39.6°	44.7°	253°
Today	5 Jul 2025	42.9	22.246 AU	23.225 AU	06h12m	+12°37'	15.2°	0.7°	227°

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/2017 E1 (Borisov) are:

            e (Eccentricity)                : 1.0032610
            q (Perihelion distance)         : 0.9078320
            i (Inclination)                 : 14.57020
            Ω (Longitude of ascending node) : 142.57660
            ω (Argument of perihelion)      : 152.79570
            L (Longitude of perihelion)     : 116.12653
            B (Latitude of perihelion)      : 6.60403
            T (Time of perihelion passage)  : 2457853.85400

            Epoch                           : 2022 May 26
            Reference                       : MPC106346

            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 gray curve is based on the absolute magnitude and slope parameter as calculated from the original MPEC, or the latest values provided by the MPC (14.00 + 5 log[∆] + 10.00 log[r]), whereas the red curve is being recalculated every 6 hours based on the available COBS/MPC observations (currently 10.88 + 5 log[∆] + 18.70 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
2025-07-05 00:00 UT   06 12 02.8   +12 37 20    23.223   22.242   14.6    0.7   224   42.9 
2025-07-05 21:50 UT   06 12 12.5   +12 37 13    23.225   22.246   15.2    0.7   227   42.9 
2025-07-06 00:00 UT   06 12 13.5   +12 37 12    23.225   22.247   15.2    0.7   227   42.9 
2025-07-07 00:00 UT   06 12 24.1   +12 37 04    23.227   22.252   15.9    0.7   229   42.9 
2025-07-08 00:00 UT   06 12 34.7   +12 36 56    23.229   22.257   16.6    0.7   231   42.9 
2025-07-09 00:00 UT   06 12 45.3   +12 36 48    23.230   22.262   17.3    0.8   233   42.9 
2025-07-10 00:00 UT   06 12 55.8   +12 36 38    23.232   22.267   18.0    0.8   235   42.9 
2025-07-11 00:00 UT   06 13 06.3   +12 36 29    23.232   22.273   18.7    0.8   237   42.9 
2025-07-12 00:00 UT   06 13 16.7   +12 36 19    23.233   22.278   19.4    0.9   239   42.9 
2025-07-13 00:00 UT   06 13 27.1   +12 36 08    23.233   22.283   20.2    0.9   240   42.9 
2025-07-14 00:00 UT   06 13 37.5   +12 35 57    23.233   22.288   21.0    0.9   242   42.9 
2025-07-15 00:00 UT   06 13 47.7   +12 35 45    23.233   22.293   21.8    1.0   243   42.9 

    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.