C/2021 A2 (NEOWISE) |
ephemeris |
date |
magn |
radius |
delta |
ra |
dec |
elong |
phase |
PA |
Perihelion | 21 Jan 2021 | 11.4 | 1.416 AU | 0.630 AU | 09h07m | -37°51' | 121.1° | 36.5° | 346° |
Nearest approach | 2 Feb 2021 | 11.1 | 1.427 AU | 0.508 AU | 07h28m | -10°42' | 143.7° | 24.1° | 41° |
Today | 1 Jul 2025 | 58.9 | 13.803 AU | 13.462 AU | 20h54m | +42°23' | 107.5° | 4.0° | 212° |
C/2021 A2 (NEOWISE)- 2025-07-01
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.)
The orbital elements of C/2021 A2 (NEOWISE) are:
e (Eccentricity) : 0.9938270
q (Perihelion distance) : 1.4162430
i (Inclination) : 107.05430
Ω (Longitude of ascending node) : 125.06230
ω (Argument of perihelion) : 338.79950
L (Longitude of perihelion) : 131.55225
B (Latitude of perihelion) : -20.22641
T (Time of perihelion passage) : 2459236.37480
P (Orbital period in years) : 3475.06
Epoch : 2025 Jun 30
Reference : MPEC 2025-A40
Classification(s): : Nearly isotropic; Returning (a < 10000 AU); External (P > 200 years)
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 (13.50 + 5 log[∆] + 10.00 log[r]), whereas the red curve is being recalculated every 6 hours based on the available COBS/MPC observations (currently 6.20 + 5 log[∆] + 41.27 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
2025-07-01 00:00 UT 20 54 06.8 +42 23 25 13.462 13.802 107.5 4.0 212 58.9
2025-07-01 00:50 UT 20 54 06.1 +42 23 27 13.462 13.803 107.5 4.0 212 58.9
2025-07-02 00:00 UT 20 53 47.0 +42 24 14 13.460 13.808 108.0 4.0 211 58.9
2025-07-03 00:00 UT 20 53 27.0 +42 25 00 13.458 13.815 108.5 4.0 210 58.9
2025-07-04 00:00 UT 20 53 06.8 +42 25 42 13.457 13.821 108.9 4.0 209 58.9
2025-07-05 00:00 UT 20 52 46.5 +42 26 20 13.455 13.827 109.4 4.0 208 58.9
2025-07-06 00:00 UT 20 52 25.9 +42 26 54 13.454 13.833 109.9 4.0 207 58.9
2025-07-07 00:00 UT 20 52 05.1 +42 27 24 13.452 13.839 110.3 3.9 207 58.9
2025-07-08 00:00 UT 20 51 44.2 +42 27 50 13.451 13.845 110.8 3.9 206 58.9
2025-07-09 00:00 UT 20 51 23.1 +42 28 13 13.450 13.851 111.2 3.9 205 58.9
2025-07-10 00:00 UT 20 51 01.9 +42 28 31 13.449 13.857 111.7 3.9 204 59.0
2025-07-11 00:00 UT 20 50 40.5 +42 28 46 13.448 13.863 112.1 3.9 203 59.0
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.