2I/Borisov |
ephemeris |
date |
magn |
radius |
delta |
ra |
dec |
elong |
phase |
PA |
Perihelion | 9 Dec 2019 | 15.6 | 1.998 AU | 1.974 AU | 11h27m | -18°35' | 77.0° | 28.7° | 290° |
Nearest approach | 28 Dec 2019 | 15.7 | 2.042 AU | 1.919 AU | 11h58m | -33°16' | 82.7° | 28.5° | 293° |
Today | 18 Oct 2025 | 35.5 | 42.048 AU | 42.415 AU | 17h53m | -53°49' | 67.4° | 1.3° | 105° |
2I/Borisov- 2025-10-18
astro.vanbuitenen.nl
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 11.2 + 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 2I/Borisov are:
e (Eccentricity) : 3.3459520
q (Perihelion distance) : 1.9977240
i (Inclination) : 44.26240
Ω (Longitude of ascending node) : 307.80240
ω (Argument of perihelion) : 209.29110
L (Longitude of perihelion) : 329.68965
B (Latitude of perihelion) : -19.96632
T (Time of perihelion passage) : 2458826.55720
Epoch : 2025 Nov 21
Reference : MPEC 2025-R69
Classification(s): : Interstellar
Ephemerides
Date Time RA (2000) DEC (2000) delta radius elong phase PA magn
2025-10-17 00:00 UT 17 53 16.1 -53 50 35 42.357 42.014 68.9 1.3 104 35.5
2025-10-18 00:00 UT 17 53 21.1 -53 49 54 42.390 42.033 68.1 1.3 104 35.5
2025-10-18 19:02 UT 17 53 25.2 -53 49 23 42.415 42.048 67.4 1.3 105 35.5
2025-10-19 00:00 UT 17 53 26.2 -53 49 14 42.422 42.051 67.3 1.3 105 35.5
2025-10-20 00:00 UT 17 53 31.5 -53 48 35 42.454 42.070 66.4 1.2 106 35.5
2025-10-21 00:00 UT 17 53 37.0 -53 47 56 42.486 42.089 65.6 1.2 106 35.5
2025-10-22 00:00 UT 17 53 42.5 -53 47 17 42.518 42.108 64.8 1.2 107 35.5
2025-10-23 00:00 UT 17 53 48.2 -53 46 39 42.550 42.127 64.0 1.2 107 35.5
2025-10-24 00:00 UT 17 53 54.0 -53 46 01 42.581 42.146 63.2 1.2 108 35.5
2025-10-25 00:00 UT 17 53 60.0 -53 45 23 42.613 42.165 62.4 1.2 109 35.5
2025-10-26 00:00 UT 17 54 06.0 -53 44 46 42.644 42.184 61.6 1.2 109 35.6
2025-10-27 00:00 UT 17 54 12.2 -53 44 10 42.675 42.203 60.8 1.2 110 35.6
2025-10-28 00:00 UT 17 54 18.5 -53 43 34 42.706 42.222 60.0 1.2 110 35.6
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.