Comet C/2023 H2 (Lemmon) will make its closest approach to the Sun on
29 October, at a distance of
0.89 AU.
From Orlando on the day of perihelion it will be visible in the dawn sky, rising at 03:41 (EDT) – 3 hours and 51 minutes before the Sun – and reaching an altitude of 22° above the north-eastern horizon before fading from view as dawn breaks at around 06:35.
The events that comprise the 2023 apparition of C/2023 H2 (Lemmon) are as
follows:
The table below lists the times when C/2023 H2 (Lemmon) will be visible from
Orlando day-by-day through its apparition:
Date | Constellation | Comet visibility |
08 Oct 2023 | Ursa Major | Not observable |
10 Oct 2023 | Canes Venatici | Not observable |
12 Oct 2023 | Canes Venatici | Not observable |
14 Oct 2023 | Canes Venatici | Visible from 06:25 until 06:27 Highest at 06:27, 22° above NE horizon |
16 Oct 2023 | Canes Venatici | Visible from 06:21 until 06:28 Highest at 06:28, 23° above NE horizon |
18 Oct 2023 | Canes Venatici | Visible from 06:18 until 06:29 Highest at 06:29, 24° above NE horizon |
20 Oct 2023 | Canes Venatici | Visible from 06:17 until 06:30 Highest at 06:30, 24° above NE horizon |
22 Oct 2023 | Canes Venatici | Visible from 06:16 until 06:31 Highest at 06:31, 24° above NE horizon |
24 Oct 2023 | Canes Venatici | Visible from 06:18 until 06:32 Highest at 06:32, 24° above NE horizon |
26 Oct 2023 | Canes Venatici | Visible from 06:22 until 06:34 Highest at 06:34, 24° above NE horizon |
28 Oct 2023 | Canes Venatici | Visible from 06:28 until 06:35 Highest at 06:35, 23° above NE horizon |
30 Oct 2023 | Ursa Major | Not observable |
01 Nov 2023 | Bootes | Not observable |
03 Nov 2023 | Bootes | Visible from 19:36 until 19:42 Highest at 19:36, 21° above NW horizon |
05 Nov 2023 | Hercules | Visible from 18:34 until 19:24 Highest at 18:34, 28° above NW horizon |
07 Nov 2023 | Hercules | Visible from 18:33 until 20:09 Highest at 18:33, 37° above NW horizon |
09 Nov 2023 | Hercules | Visible from 18:32 until 20:47 Highest at 18:32, 47° above W horizon |
11 Nov 2023 | Aquila | Visible from 18:31 until 21:08 Highest at 18:31, 53° above W horizon |
13 Nov 2023 | Aquila | Visible from 18:30 until 21:13 Highest at 18:30, 50° above SW horizon |
15 Nov 2023 | Capricornus | Visible from 18:29 until 21:07 Highest at 18:29, 44° above SW horizon |
17 Nov 2023 | Capricornus | Visible from 18:29 until 20:54 Highest at 18:29, 38° above S horizon |
A more detailed table of C/2023 H2 (Lemmon)’s position on each night is
available here.
A diagram of the orbit of C/2023 H2 (Lemmon) is
available here.
Finder chart
The chart below shows the path of C/2023 H2 (Lemmon) over the
course of its apparition, as calculated from the orbital elements published by the
Minor Planet Center (MPC).
It is available for download, either on dark background, in
PNG,
PDF or
SVG formats,
or on a light background, in
PNG,
PDF or
SVG formats.
It was produced using
StarCharter.
Comet brightnesses
Comets are intrinsically highly unpredictable objects, since their brightness depends on the scattering of
sunlight from dust particles in the comet’s coma and tail. This dust is continually streaming away from the
comet’s nucleus, and its density at any particular time is governed by the rate of sublimation of the ice in
the comet’s nucleus, as it is heated by the Sun’s rays. It also depends on the amount of dust that is mixed
in
with that ice. This is very difficult to predict in advance, and can be highly variable even between
successive
apparitions of the same comet.
In consequence, while the future positions of comets are usually known with a high degree of confidence,
their future brightnesses are not. For most comets, we do not publish any magnitude estimates at all. For
the few comets where we do make estimates, we generally prefer the BAA’s magnitude parameters to those published
by the Minor Planet Center, since they are typically updated more often.
Based on the magnitude parameters published for this comet by the
BAA Comet Section,
we estimate that it may be around
mag 7 on 29 October 2023.
This estimate is based on observations that the BAA has received from amateur astronomers, assuming that its
current level of activity will remain constant.
This comet is not expected to be visible to the naked eye, but might be visible
through bird-watching binoculars.
The comet’s position at perihelion will be:
Object | Right Ascension | Declination | Constellation | Magnitude |
Comet C/2023 H2 (Lemmon) | 13h34m10s | 50°05’N | 7.1 |
The coordinates are given in J2000.0.
The sky on 29 Oct 2023
Source
This event was automatically generated on the basis of orbital elements
published by the
Minor Planet Center (MPC)
,
and is updated whenever new elements become available. It was last updated
on 26 Oct 2023.
Image credit
© Andy Roberts 1997. Pictured comet is C/1995 O1 Hale-Bopp.