|
C/2021 Y1 (ATLAS) |
| ephemeris |
date |
magn |
radius |
delta |
ra |
dec |
elong |
phase |
PA |
| Nearest approach | 12 Dec 2022 | 14.1 | 2.614 AU | 1.691 AU | 03h59m | +05°42' | 154.5° | 9.3° | 45° |
| Perihelion | 1 May 2023 | 13.8 | 2.032 AU | 2.514 AU | 04h43m | -24°14' | 50.7° | 22.6° | 137° |
| Today | 20 Oct 2025 | 23.6 | 8.711 AU | 9.492 AU | 16h08m | -13°40' | 36.4° | 3.9° | 91° |
C/2021 Y1 (ATLAS)- 2025-10-20
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 8.4 + 5 log[∆] + 11.0 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/2021 Y1 (ATLAS) are:
e (Eccentricity) : 1.0016810
q (Perihelion distance) : 2.0323810
i (Inclination) : 77.18090
Ω (Longitude of ascending node) : 244.76590
ω (Argument of perihelion) : 245.85250
L (Longitude of perihelion) : 271.09686
B (Latitude of perihelion) : -62.84208
T (Time of perihelion passage) : 2460065.50630
Epoch : 2025 Oct 19
Reference : MPEC 2024-GJ3
Classification(s): : Nearly isotropic; New (a > 10000 AU)
Ephemerides
Date Time RA (2000) DEC (2000) delta radius elong phase PA magn
2025-10-19 00:00 UT 16 07 40.2 -13 40 31 9.468 8.701 37.6 4.0 92 23.6
2025-10-20 00:00 UT 16 08 03.5 -13 40 36 9.485 8.708 36.7 3.9 91 23.6
2025-10-20 09:25 UT 16 08 12.7 -13 40 38 9.492 8.711 36.4 3.9 91 23.6
2025-10-21 00:00 UT 16 08 27.0 -13 40 41 9.502 8.715 35.9 3.8 91 23.6
2025-10-22 00:00 UT 16 08 50.7 -13 40 46 9.519 8.722 35.0 3.8 90 23.6
2025-10-23 00:00 UT 16 09 14.6 -13 40 50 9.535 8.730 34.1 3.7 90 23.6
2025-10-24 00:00 UT 16 09 38.6 -13 40 55 9.551 8.737 33.2 3.6 90 23.6
2025-10-25 00:00 UT 16 10 02.8 -13 40 59 9.567 8.744 32.4 3.5 89 23.6
2025-10-26 00:00 UT 16 10 27.2 -13 41 03 9.583 8.751 31.5 3.4 89 23.6
2025-10-27 00:00 UT 16 10 51.7 -13 41 07 9.599 8.758 30.6 3.3 88 23.6
2025-10-28 00:00 UT 16 11 16.3 -13 41 10 9.614 8.766 29.8 3.2 88 23.6
2025-10-29 00:00 UT 16 11 41.1 -13 41 13 9.629 8.773 28.9 3.1 87 23.6
2025-10-30 00:00 UT 16 12 06.0 -13 41 16 9.644 8.780 28.0 3.0 87 23.7
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.
