C/2018 U1 (Lemmon) |
ephemeris |
date |
magn |
radius |
delta |
ra |
dec |
elong |
phase |
PA |
Nearest approach | 18 Jun 2021 | 15.2 | 5.095 AU | 4.133 AU | 17h19m | -03°37' | 159.1° | 4.1° | 161° |
Perihelion | 2 Nov 2021 | 15.9 | 4.985 AU | 5.819 AU | 16h31m | -22°10' | 30.1° | 5.7° | 99° |
Today | 4 Aug 2025 | 20.1 | 10.795 AU | 11.148 AU | 08h02m | -48°49' | 67.2° | 5.0° | 195° |
C/2018 U1 (Lemmon)- 2025-08-04
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/2018 U1 (Lemmon) are:
e (Eccentricity) : 1.0000190
q (Perihelion distance) : 4.9853430
i (Inclination) : 108.32580
Ω (Longitude of ascending node) : 75.51340
ω (Argument of perihelion) : 180.34220
L (Longitude of perihelion) : 75.40580
B (Latitude of perihelion) : -0.32484
T (Time of perihelion passage) : 2459520.55290
Epoch : 2025 Aug 03
Reference : MPC184408
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 (5.00 + 5 log[∆] + 10.00 log[r]), whereas the red curve is being recalculated every 6 hours based on the available COBS/MPC observations (currently 6.31 + 5 log[∆] + 8.25 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
2025-08-04 00:00 UT 08 02 04.8 -48 49 36 11.143 10.791 67.2 5.0 194 20.1
2025-08-04 15:31 UT 08 02 20.1 -48 49 56 11.148 10.795 67.2 5.0 195 20.1
2025-08-05 00:00 UT 08 02 28.5 -48 50 08 11.151 10.797 67.1 5.0 195 20.1
2025-08-06 00:00 UT 08 02 52.0 -48 50 44 11.158 10.802 67.0 5.0 196 20.1
2025-08-07 00:00 UT 08 03 15.3 -48 51 25 11.165 10.808 66.9 5.0 197 20.1
2025-08-08 00:00 UT 08 03 38.5 -48 52 11 11.172 10.813 66.8 4.9 198 20.1
2025-08-09 00:00 UT 08 04 01.6 -48 53 00 11.179 10.819 66.7 4.9 199 20.1
2025-08-10 00:00 UT 08 04 24.4 -48 53 54 11.186 10.824 66.6 4.9 200 20.1
2025-08-11 00:00 UT 08 04 47.1 -48 54 52 11.192 10.829 66.6 4.9 201 20.1
2025-08-12 00:00 UT 08 05 09.6 -48 55 54 11.199 10.835 66.5 4.9 201 20.1
2025-08-13 00:00 UT 08 05 31.9 -48 57 00 11.205 10.840 66.4 4.9 202 20.1
2025-08-14 00:00 UT 08 05 54.0 -48 58 11 11.212 10.846 66.4 4.9 203 20.1
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.