Meteor Showers

Orionids
The Orionids are the major and fairly reliable meteor shower in October. Like the May η-Aquariid shower, the Orionids are associated with Comet 1P/Halley. During this second pass through the stream of the comet, slightly fewer meteors are seen than in May, but conditions are more favourable. In both showers the meteors are very fast and many leave persistent trains. The maximum is on 21-22 October although there is a very broad maximum, lasting about a week and roughly centred around that date, with hourly rates in the region of 25. Occasionally, rates are higher at around 50-70 per hour. This year, the Moon is first quarter, so conditions are reasonably favourable.

Southern Taurids
The faint shower of the Southern Taurids peaks on 10-11 October. The maximum occurs when the Moon is a waning crescent, so conditions are more favourable than those for the Orionids.

Northern Taurids
Towards the end of the month (around the 20th) the Northern Taurids begins to show activity, which peaks 12-13 November. The parent comet for both Taurid showers is Comet 2P/Encke. The meteors in both Taurid showers are relatively slow and bright.

Draconids
A minor shower, the Draconids, starts on 6th October ‘23, peaking on 8-9 Oct.

October Overview

Northern Sky
Ursa Major is grazing the horizon in the north, while overhead are the constellations of Cepheus, Cassiopeia and Perseus, with the Milky Way between Cepheus and Cassiopeia at the zenith. 

Auriga is now clearly visible in the east, as is Taurus with the Pleiades, Hyades and orange Aldebaran.  Also in the east, Orion and Gemini are starting to rise clear of the horizon.

The constellations of Bootes and Corona Borealis are now essentially lost to view in the northwest and Hercules is also descending towards the western horizon.

The three stars of the Summer Triangle are still clearly visible, (made up from the three brightest stars of Vega in Lyra, Deneb in Cygnus and Altair in Aquila) although Aquila and Altair are beginning to approach the horizon to the west.

Towards the end of the month (29th October ’23) Summer Time ends in Europe, with Britain reverting to Greenwich Meantime (GMT) and Europe to Central European Time.
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Southern Sky
At this time of the year we see to the south the late-Summer early-Autumn constellations of Capicornus and Aquarius as we lose the Summer ones of Ophiuchus and Sagittarius in the west. 

Then later in the evening we start to see the constellations of Gemini, Taurus, and Orion, a sure sign that winter is just around the corner.

For the enthusiast of open clusters there is plenty of choice in and around Auriga.  Apart from the familiar trio of M36, M37 and M38 there are a number of NGC objects, the brightest of which is NGC 2281 an open cluster at magnitude +5.4.

Towards the south we find the large but indistinct shape of Cetus (just rising on the main star chart) on the meridian, whilst above it the two fish of Pisces envelop the east and south of Pegasus.

Cetus is home to Mira ‘The Wonderful’, also known as omicron Ceti and one of the earliest variable stars to be discovered. With a period of 332 days, not only does its brightness vary, but its brightness at successive maxima and minima also varies. The magnitude range is from +3.5 to +9 (too faint to see with the eye; for reference, in a dark sky, the unaided eye can barely detect a magnitude 6 star). The latest maximum brightness was predicted to be on 13 Jun ’23.

Andromeda straddles the meridian, with M31 – and its two immediately attendant satellite galaxies – at an enviable altitude of 80°. Looking west, that area of sky is dominated by the Summer Triangle although it is well past its best, with Altair (the closest to the horizon) being just 18° from setting.

North of Aquila lies Cygnus and between the two birds can be found the small constellations of Sagitta (the arrow) and Vulpecula (the fox). The former has few deep sky objects within easy reach of amateur telescopes, with M71 – a globular cluster at magnitude +8.5 – being the brightest. There are also a number of planetary nebulae which range from 10th to 12th magnitude.

Vulpecula has more of interest including, of course, the asterism known as ‘The Coathanger’ or, more properly, Collinder 399. There are a number of open clusters, the brightest of which is NGC 6885 at mag +6.00, but no easily observable galaxies due to Vulpecula’s proximity to the galactic plane. There is one planetary nebula, M27, but at mag 7.6 it would benefit from the application of an aperture around 250mm.

At this time of year, the Milky Way appears almost due west on the horizon and passes through this area, providing rich pickings for those who take pleasure from scanning with nothing more than a pair of binoculars.

The northern horizon sees Ursa Major close by as it straddles the meridian below the pole. The angle of the Bear’s tail tells us that Arcturus is below the horizon with most of Hercules soon to follow, although from the the UK, M92 – the strong man’s no.2 globular cluster – is just circumpolar.

The position of the Bear also tells us that Cassiopeia must be on the meridian, and she does in fact at this time have the zenith within her boundaries. This make it a perfect time to look at the many open clusters, my favourite of which is NGC457, The Owl or ET cluster. So called as it looks like on owl or ET from the 1982 Spielberg film. Close to Cassiopeia is this months Object Challenge, (M76) The Little Dumbbell Nebula.

October’s Object Challenge

(M76) The Little Dumbbell Nebula , (*Planetary Nebula). The nebula lies at an approximate distance of 2,500 light years from Earth and has an apparent magnitude of 10.1.

Large binoculars and small telescopes show M76 as a small, diffuse point of light. The nebula is better seen through medium-sized telescopes. 8-inch telescopes reveal its two lobes and the dark lane separating them, while large instruments show both the double-lobed structure of M76 and the faint halo surrounding it.

*Planetary nebula, any of a class of bright nebulae that are expanding shells of luminous gas expelled by dying stars. Observed telescopically, they have a relatively round compact appearance rather than the chaotic patchy shapes of other nebulae.

Comets

Comet C/2023 H2 Lemmon was discovered on 28 April ’23 in images taken with the 1.5-m reflector of the Mt Lemmon Survey.

The comet reaches perihelion at 0.9 au on 29 October ’23. On 11 Nov ’23 it passes 0.2 au from the Earth, when it may reach at least 10th magnitude and may get much brighter to make it a possible binocular object. It will then be in the evening sky and moving rapidly south.

At the time of writing, it was last observed on 18th Sep ’23 at estimated mag 9.3, significantly brighter than expected, although with a large diffuse coma.

For up-to-date information look at www.heavens-above.com  or www.in-the-sky.org and you can pinpoint its location.

The yellow line shows the path of the comet from 29 Sep to 30 Nov, from right to left in 10-day increments.

Months are labelled as IX for Sep, X for Oct and XI for Nov.

ISS

The ISS isn’t visible for us until the 21st October until 04th November ‘23 when it will be a morning object.