A monthly look at astronomical events in the sky and on Earth

Compiled by Steve Sawyer

Hi welcome to September What’s Up.. I hope everyone has booked their tickets for York Astro’s 50th Anniversary on the 2nd, as the program of speakers is excellent!
So onto what’s happening this month, well dark skies return with the arrival of Autumn and the time around the equinox has proven to be an excellent time for Aurora spotting. There’s also a comet to look out for too.

Something else I found out about September is the Earth’s atmosphere tends to be more stable, resulting in better viewing conditions for telescopic observations. This stability minimizes the blurring effects caused by atmospheric turbulence, allowing for clearer and sharper views. There are several reasons for this. Cooling temperatures, reduced convective heating, a weaker jet stream, and settled weather patterns contribute to calmer and clearer air.

So what’s on this month?

Sky Diary

Date	Time	Description
4th		Moon near Jupiter
5th		Moon near Pleiades
6th		Last Quarter Moon
9th		Peak of the e-Perseids
10th		Moon near Caster and Pollux
11th		Moon near Venus
12th		Moon near Venus
13th		Moon near Regulus
15th		New Moon
18th		Venus at Max brightness
21st		Neptune at oposition
22nd		First Quarter Moon & Mercury Elogation
23rd		Autumn Equinox
26th		Moon near Saturn
29th		Full Moon (last Supermoon of the year)

Sky Maps

Looking South on the 15th at 22:00

Looking North on the 15th at 22:00

Septembers Objects

The Sun

Not too many active sunspots at the time of writing but there are around 94 current active sunspots and 0 spotless days so far this year.

Whilst solar activity is independent of the the Earths tilt as we approach the time of the equinox the Earth’s magnetic field and the solar wind are aligned in a way that can increase the intensity of geomagnetic storms. This alignment allows solar wind particles to interact more effectively with Earth’s magnetosphere, resulting in a higher likelihood of auroras being observed. so as we move towards the autumn equinox activity may increase. So keep a look out for activity.

Resources

For more info on the sun and solar weather look here : –

https://www.swpc.noaa.gov/communities/space-weather-enthusiasts

And our own Met-office have an excellent space weather forecast page here Space Weather – Met Office

The Moon

The full moon this month takes place on the 29th and is the last supermoon of 2023. Septembers Moon is commonly know as the harvest moon.

Ai generated image of the harvest Moon, I think this would make a good Stephen King book cover!

The Harvest Moon occurs around the time of the autumnal equinox, which falls between September 21st and 23rd in the Northern Hemisphere. During this period, the angle between the ecliptic—the plane of Earth’s orbit around the Sun—and the horizon becomes shallow, causing the Moon to rise closer to the horizon.

Unlike other phases of the Moon, where its rise times vary each day, the Harvest Moon rises around the time of sunset for several consecutive nights. This unique characteristic results in a shorter time gap between sunset and moonrise. In some cases, the time difference can be as little as 20-30 minutes, as opposed to the usual 50 minutes or more.

The combination of the Harvest Moon’s shallow angle of ascent and its synchronized rise with sunset provides several evenings of bright moonlight. This extra illumination was historically beneficial to farmers during the autumn harvest, as they could work late into the evening with the aid of the Moon’s light.

The Harvest Moon’s proximity to the horizon during its rise can cause it to appear larger and more reddish or orange than usual. This reddish hue is a result of the Moon’s light passing through more of Earth’s atmosphere, which scatters shorter wavelengths of light and allows the longer wavelengths (such as red and orange) to dominate.

See the sky diary for this months lunar events as there are some nice viewing opportunities .

A full lunar calendar can be found here :-

https://www.mooninfo.org/moon-phases/2022.html

Planets

Mercury

Not visible at the start of the Month but from the 20th September, Mercury (mag –0.5) rises around 5 am, well to the lower left of Venus. It’s at maximum separation from the Sun on 22 September.

Venus

A Morning object Venus is one of the planetary highlights of the month. By the end of September, the planet is rising as 3 am, so early we see it against a truly dark sky, and at its maximum brightness (magnitude –4.5). There’s a pretty sight when the crescent Moon hangs nearby on the mornings of 11 and 12 September

Mars

Not visible this month

Jupiter

Visible in Aries from around midnight until morning.

Saturn

Saturn lies in Aquarius and is above the horizon all night long and reaches it’s highest point in the sky this month. Saturn’s rings are currently facing with the northern edge tilted towards Earth

Uranus

Also found in Aries and rises at around 9pm.

Neptune

September is a good time to view this small blue planet. Neptune can be found in Pisces and is visible all night.

Meteor Showers

Aurigrids

1st September is the peak of the Aurigrids but they’re active until the 5th. Somewhat spoilt by a 98% lit moon. The radiant is in Auriga which is high above the horizon.

e-Perseids (Epsilon Perseids)

Not to be confused with Augusts Perseids, as they come from a different comet. These peak is on the 9th September but can be seen from the 5th-21st, with the radiant being in Perseus. This is a weaker shower with around 5-10 meteors per hour during the peak.

Comets

So we have a new comet to look out for!
Discovered on August 11th by Japanese amateur astronomer Hideo Nishimura and now named after him comet C/2023 P1 (Nishimura) is currently in the constellation Cancer with a mag of 7.0 and is slowly getting brighter.

How to find it

September 5: C/2023 P1 (mag 5.5, elongation 27.7°) enters the constellation Leo.
September 6: C/2023 P1 (mag 5.2, elongation 26.3°) passes 0°6′ away from the star Ras Elased Australis (mag 2.95) in the constellation Leo.
September 9: C/2023 P1 (mag 4.2, elongation 21.2°) passes 0°33′ away from the star Adhafera (mag 3.4) in the constellation Leo.
September 12: C/2023 P1 (mag 3.3, elongation 15.5°) reaches its closest approach to the Earth at a distance of 0.85 AU and passes 1°38′ away from the star Zosma (mag 2.6) in the constellation Leo.
September 14: C/2023 P1 (mag 2.7, elongation 12.7°) passes 0°6′ away from the star Denebola (mag 2.1) in the constellation Leo.
September 15: C/2023 P1 (mag 2.5, elongation 12.1°) enters the constellation Virgo.
September 17: C/2023 P1 (mag 2.3, elongation 12.2°) reaches perihelion in the constellation Virgo.
September 21: C/2023 P1 (mag 3.2, elongation 14.0°) passes 1°23′ away from the star Porrima (mag 2.7) in the constellation Virgo.

These are the other viewable comets this month, the ones listed below start at mag 7 and go to mag 13.

Name	Mag
C/2023 E1 (ATLAS)	11
C/2020 V2 (ZTF)	9
103P/Hartley 2	7
2P/Encke	11
12P/Pons- Brooks	11
C/2022 A2 (PanSTARRS)	12
237P/LINEAR	12
C/2022 W3 (Leonard)	13
126P/IRAS	13
C/2019 T4 (ATLAS)	13
C/2021 X1 (Maury- Attard)	13

Deep Sky (DSO’s)

This month its the turn of Aquarius. Whilst not among the most striking constellations, Aquarius, also known as the Water Carrier, boasts an ancient lineage. Its origins trace back to antiquity, with the Babylonians linking this celestial region to water due to the Sun’s transit during the rainy season. In Greek depictions, Aquarius takes the form of a figure pouring from a Water Jar, represented by a central cluster of four faint stars. This action is portrayed as the liquid cascading downward onto Piscis Austrinus, the Southern Fish constellation.

NGC 7293 (Helix Nebula)

The Helix Nebula (NGC 7293) is a nearby and notable planetary nebula in the Aquarius constellation. Its intricate structure resembles a cosmic eye and represents the final stage of a star’s life. Located about 700 light-years away, the nebula showcases a central star that once resembled our Sun.

M2

Messier 2 (M2) is a prominent globular star cluster in the Aquarius constellation. Located around 37,000 light-years from Earth, M2 showcases a collection of densely packed old stars spanning about 175 light-years in diameter. Its bright appearance and larger size make it an accessible target and unlike some clusters, M2’s stars are resolvable, allowing appreciation of the individual stars within its structure

NGC 7727

NGC 7727 is an irregular galaxy. Its classification as an irregular galaxy comes from its lack of defined spiral or elliptical structure, giving it a unique and unstructured appearance. Positioned at a considerable distance from Earth (83 million light years), NGC 7727 showcases an intricate and visually engaging arrangement of stars, gas, and dust.

NGC 7009 (Saturn Nebula)

This planetary nebula is known for its resemblance to the planet Saturn. It features a central star shrouded in a gaseous ring, resulting in a striking visual similarity to the ringed planet.

Messier 72 (M72)

Another globular cluster in Aquarius, M72 presents a more subdued appearance compared to M2. Its fainter stars and smaller apparent size make it a rewarding challenge

Double Stars

Aquarius offers a few intriguing double stars, such as Psi Aquarii and Epsilon Aquarii.

ISS and other orbiting bits

Date	Visible	Max Height*	Appears
Thu Aug 31, 3:49 AM	3 min	33°	33° above SSE
Thu Aug 31, 5:21 AM	7 min	58°	10° above WSW
Fri Sep 1, 3:02 AM	1 min	15°	15° above ESE
Fri Sep 1, 4:35 AM	5 min	54°	27° above WSW
Sat Sep 2, 3:48 AM	3 min	47°	47° above SSE
Sat Sep 2, 5:21 AM	7 min	54°	10° above W
Sun Sep 3, 3:02 AM	1 min	17°	17° above E
Sun Sep 3, 4:35 AM	5 min	58°	32° above WSW
Mon Sep 4, 3:48 AM	3 min	50°	50° above SE
Mon Sep 4, 5:21 AM	6 min	41°	12° above W
Tue Sep 5, 3:01 AM	1 min	16°	16° above E
Tue Sep 5, 4:34 AM	4 min	49°	35° above WSW
Wed Sep 6, 3:48 AM	2 min	37°	37° above SE
Wed Sep 6, 5:21 AM	5 min	27°	13° above W
Thu Sep 7, 3:02 AM	< 1 min	10°	10° above ESE
Thu Sep 7, 4:35 AM	3 min	34°	34° above SSW
Fri Sep 8, 3:48 AM	1 min	17°	17° above SE
Fri Sep 8, 5:22 AM	3 min	16°	14° above SW
Sat Sep 9, 4:36 AM	1 min	16°	16° above S

Check the website listed for sightings after this date . Use the this NASA website for exact timings for York overpasses. York, England, United Kingdom | Sighting Opportunity | Spot The Station | NASA

Useful Resources

https://www.spacedaily.com/

http://www.n3kl.org/sun/noaa.html

http://skymaps.com/downloads.html

http://www.seasky.org/astronomy/astronomy-calendar-2022.html

https://www.rmg.co.uk/stories/topics/what-are-names-full-moons-throughout-yearhttp://www.deepskywatch.com/deepsky-guide.html

https://www.constellation-guide.com/

Top 10 Winter Sky Targets for Skywatchers | Space

and of course the sky at night magazine!