18:56
each night, when its radiant point rises above your eastern horizon. It will then remain active until dawn breaks around 06:16.

The shower is likely produce its best displays in the hours around 01:00 PST, when its radiant point is highest in the sky.

At this time, the Earth’s rotation turns Los Angeles to face optimally towards the direction of the incoming meteors, maximising the number that rain vertically downwards, producing short trails close to the radiant point. At other times, there will be fewer meteors burning up over Los Angeles, and they will tend to enter the atmosphere at an oblique angle, producing long-lived meteors that may traverse a wide area of the sky before completely burning up.

The shower is expected to reach peak activity at around 09:00 PST on 9 December 2023, and so the best displays might be seen before dawn on 9 December.

Observing prospects

At its peak, the shower is expected to produce a nominal rate of around

2 meteors per hour (ZHR).
However, this zenithal hourly rate is calculated assuming a perfectly
dark sky and that the radiant of the shower is situated directly overhead. In
practice, any real observing sight will fall short of these ideal conditions.
The number of meteors you are likely to see is thus lower than this, and can be
estimated using the

ZHR formula.

From Los Angeles, the radiant of the shower will appear at a peak altitude of 63° above your horizon, and on the basis of this, we estimate that you may be able to see up to 1 meteors per hour at the shower’s peak.

The shower will peak close to new moon, and so moonlight will present minimal interference.

The origin of the shower

Meteor showers arise when the Earth passes through streams of debris left
behind in the wake of comets and asteroids. Over time, the pieces of grit-like
debris in these streams distribute themselves along the length of the parent
object’s orbit around the solar system.

Shooting stars are seen whenever one of these pieces of debris collides with
the Earth’s atmosphere, typically burning up at an altitude of around 70 to 100
km.

On certain days of the year the Earth’s orbit passes through particularly dense
streams, associated with comets or asteroids which have vented particularly
large amounts of solid material to space, and this gives rise to an annual
meteor shower. Such showers recur on an annual basis, whenever the Earth passes
the particular point in its orbit where it crosses the particular stream of
material.

The meteors that are associated with any particular meteor shower can be
distinguished from others because their paths appear to radiate outwards from a
common point on the sky, which points back in the direction from which their
orbital motion brought them.

This is because the grit particles in any particular stream are travelling in
almost exactly the same direction when they cross the Earth’s orbit, owing to
having very similar orbits to the parent object they came from. They strike the
Earth from almost exactly the same direction, and at the same speed.

To see the most meteors, the best place to look is not directly at the radiant
itself, but at any dark patch of sky which is around 30–40° away from
it. It is at around this distance from the radiant that the most meteors will
be seen.

By determining the position of this radiant point on the sky, it is possible to
work out the orbit of the stream giving rise to any particular meteor shower.
It is sometimes even be possible to identify the particular body responsible
for creating the debris stream, if there is a known comet or asteroid with a
very similar orbit.

The radiant of the Monocerotid meteor shower is at around right ascension

06h40m, declination 8°N, as shown by the green circle on the planetarium above.

The sky on 9 Dec 2023

Source

The position of the radiant of this shower, and its predicted hourly rate, were
taken from International Meteor Organisation’s

List of Meteor Showers.

Image credit

© Jacek Halicki 2016. Perseid meteor seen in 2016 from Poland.