Eyes on the Night Sky – September 2023

Sam Price — Thu, 24 Aug 2023 10:08:47 +0000

Welcome to this month’s edition of Eyes on the Night Sky, where the Elan Valley Dark Sky Team pick out their favourite night sky objects to study in the September night sky with the unaided eye, binoculars or telescopes.

The sun sets at around 8pm this time of year and darkness falls at around 10pm, which isn’t too late to look for deep sky objects such as galaxies.

September Constellations

The Summer constellations continue their march into the western sky during this month; the constellations of Hercules and Lyra relatively well-placed. Cygnus is directly South with the Milky Way meandering through it, whilst the constellation of Pegasus with its enormous square asterism rises from the east with the constellation of Andromeda in its wake.

You can download the printable constellation map from here (credit: Dominic Ford, author in-the-sky.org).

The New Moon falls on 15^th September and the Full Moon on 29^th September.

Credit & Copyright: Dan Bartlett

Comet C/2023 P1 Nishimura

We may have a special visitor in the early morning skies in the early part of September: Comet C/2023 P1 Nishimura. Recently discovered on 11^th August by Hideo Nishimura, its closest approach to Earth will be on 12^th September and may be spotted rising in the North-east at around 5am.

The best chance to see it relatively well-placed in the sky is around 4am on 2^nd September. It reaches perihelion, where it is closest to the Sun, on 17^th September. At the time of writing, it is currently bright enough to be seen by telescopes but could get bright enough to be seen with binoculars during the first week of September. Cometary activity and brightness are extremely hard to predict so keep an eye on reports and updates as they happen.

On 5^th September at around midnight, look to the east and you will see the waxing gibbous Moon with Jupiter on the right-hand side and the Pleiades Star Cluster on the left. Uranus lies in the 8-o clock position from the Moon and can both be seen with binoculars.

Bright Venus rises at around 4am at the beginning of the month. On 12^th September, try to spot Venus to the right of the waning crescent moon; it is only 6% illuminated and by 5am, you may be able to see Earthshine on the lunar surface. If you have a telescope handy, take a look at Venus – the planet will also be in phase at about 20% full, looking like a little crescent Moon.

The best time to spot Neptune will be on 19^th September, where it will be at its brightest and at its closest approach to earth (Opposition). At 2.7 billion miles form Earth, this ice giant can only be seen through powerful telescopes. You can try finding it with a 4-6 inch telescope where it may appear like a blue steady disk but it is a challenge to find.

On 22^nd September, Mercury will be at greatest western elongation which means it will be at the highest point above the horizon. The planet will lie low in the eastern sky before the sun rises.

The September Equinox falls on 23^rd September, where the Sun will reach the Zenith (highest point in the sky) for those living along the Earth’s equator. For the rest of us, there will be an equal amount of daylight and night. It is also the first day of Autumn.

Galaxies Galore

September is a good time to study a few galaxies – in fact, a galaxy that is our nearest neighbour at 2.5 million light years distant.

Andromeda Galaxy (M31)

RA 0h 42m 44s | Dec +41° 16′ 9″

Andromeda Galaxy (M31) is a spectacular object that can be seen with the unaided eye in a rural sky but starts to look incredible through binoculars as a well-defined ellipse with a bright core. With a telescope of 8 inches of aperture and above in a dark sky, you may see hints of a dark dust lane. You will also see two other galaxies, M110 which lies above Andromeda Galaxy, and M32, which is the fuzzy ellipse just below.

Triangulum Galaxy (M33)

RA 1h 33m 50s | Dec +30° 39′ 37″

The Triangulum Galaxy is 2.73 million light years away and is situated in the constellation of Triangulum. It is the third largest galaxy in the Local Group, with Andromeda Galaxy being the largest containing 1 trillion stars, our Milky Way Galaxy with 400 billion stars and the Triangulum Galaxy comprising 40 billion stars. You many be able to see this galaxy with the unaided eye in very dark skies but it can be spotted with binoculars as a ‘fuzzy blob’. Through telescopes of 8 inches aperture and larger, you may start to see the spiral arms, which become more apparent with increases in telescope size.

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Eyes on the Night Sky – May 2023

Sam Price — Tue, 02 May 2023 08:16:52 +0000

As we move towards the late spring/early summer months, the dusk sky deepens to a deep blue twilight all night.

Scotland is the first country in the UK to lose the night in early May, followed by the lower latitudes, finishing with the south towards the end of May. This means that the nights don’t get dark enough to study deep sky objects such as galaxies, globular clusters and nebulae.

It’s a great time of year to branch out into other areas of visual study, such as the Moon and planets, whether you use your eyes, binoculars or even a small telescope.

May Constellations

The constellations of Gemini and Auriga sets in the west at around 10pm and Ursa Major is very well-placed at the zenith. Leo marches westwards during the month of May and Virgo takes pride of place in the south. The constellation of Corona Borealis (Northern Crown) is a wonderful array of stars to look out for in the eastern sky, resembling a C shape or a celestial crown.

You can download the printable constellation map from here (credit: Dominic Ford, author in-the-sky.org)

The Full Moon falls on 5 May and the New Moon on 19 May.

Noctilucent Clouds

Noctilucent clouds emerge into the night sky from the middle of this month so get outside when darkness falls and look north. They usually appear from 11pm-midnight and then a couple of hours before sunrise – they can be a stunning sight to behold. Also known as Polar Mesospheric clouds, these diffuse, high-latitude ice crystals are illuminated by the Sun, as it sets above 18 degrees below the horizon. This is why the summer nights don’t get fully dark. You can see the residual light cast by the Sun move as a light dome along the western horizon, along the north and to the east before rising.

The Moon

During the summer season the moon can provide a fascinating experience for the stargazer with interesting features to discover. When it is in phase, the mountains and craters cast shadows along the terminator – the area between light cast by the sun and the shadow of the moon which can look great in small telescopes under high magnification. The features on the Moon have designations and areas just like locations on Earth. Here are a few features to discover:

The Vallis Alpes

If you have a small telescope this can be a fascinating object to study when the Moon is in phase and the shadows of the mountains and craters are cast on the Moon’s surface. This fascinating jagged valley cuts straight through the Alpes or better known as the Lunar Alps.

Hadley Rille

If you have a larger telescope, take a look at the area of the Moon explored by astronauts on the Apollo 15 project. If the conditions allow under high magnification, try to spot the wiggly line running along the valley floor.

Crater Gassendi

Craters can be fascinating objects to study when the Moon is in phase, as the crater’s rim can cast shadows on the lunar surface. You may even be able to spot rilles (they look a bit like veins) running along the floor.

Rupes Recta

Rupes Recta is a fault line that runs for 110km along the lunar surface. The shelf is over 270m high and it also known as the Straight Wall. The crater that is situated halfway along the Straight Wall is crater Birt.

Coathanger Asterism

When darkness falls, look for the star Altair in the constellation of Aquila.

Look for the fork-shaped constellation of Sagitta and above that, a two-star constellation called Vulpecula. Look in between the constellations of Vulpecula and Sagitta and raise your binoculars to your eyes. Slowly scan the sky until you see an upside-down coat hanger.

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