Eyes on the Night Sky – September 2021
The month of September signifies the beginning of Autumn. On 22nd September, the Sun crosses the celestial equator from north to south which is directly above the Earth’s equivalent. The hours of day and night are the same on this day. This is known as the autumn equinox.
For some, the ‘nights drawing in’ marks the end of long summer evenings but the darkness shouldn’t stop people from getting outside when it is clear. It’s a great time of year to see planets, nebulae and star clusters if whether you have a telescope, binoculars or even your eyes.
The full Moon rises in the east on 20th September. Watch this ‘Harvest Moon’ rise in the east at around 7.40pm. The new Moon falls on 6th September.
Jupiter, the Moon and Saturn
On 17th September, look out for an attractive, three-object conjunction emerging into the sky as darkness falls. Resembling the three points of an upside-down isosceles triangle, Jupiter, the Moon and Saturn remain close to each other all night and will provide a stunning photographic object.
This month, it is a great time to find Neptune as it is at opposition on 14th September. It will be fully illuminated by the Sun which will make it discoverable using six-inch telescope. It won’t look outstanding as it appears as a fuzzy grey-blue object.
A Few Telescope Treasures
We are spoilt for choice this month as the evenings draw in. Try and find some great nebulae in the constellation of Cygnus.
North American Nebula (NGC7000) location: RA 20h 59m 17s | Dec +44° 31′ 44″
Look for the North American Nebula (NGC7000), the Fireworks Galaxy (NGC 6946) and the Blinking Planetary Nebula (NGC 6826). A UHC filter would be good to use as you can pick out detail and can sometimes increase contrast in Nebulae. In a dark sky, The North American Nebula appears as a foggy patch of light and it is best seen with low magnification, as it covers a region more than ten times the area of the full Moon.
Fireworks Galaxy (NGC 6946) ) location: RA 20h 34m 52.3s | Dec +60° 09′ 14″
The Fireworks Galaxy earned its name from looking like a Catherine Wheel. This face-on spiral galaxy has an interesting history, having experienced 10 supernovae in the last 100 years, which is unusual. Not only does it look like a firework, it acts like one. It lies 22 million light years away and was first discovered by William Herschel in 1798. You may be able to find it with a telescope of 6 inches aperture and above; larger telescopes of 10 inches and above may reveal a spiral structure.
Blinking Planetary Nebula location: RA 19 44 48.18 | Dec +50° 31' 31.45"
The Blinking Planetary Nebula provides a challenge for keen observers. Through an eight-inch telescope, it is a fun object to view as it appears to blink when viewed directly. Look away and at it again for repeated affect. This object lies 2000 light years away from us. This is thought to be caused by the effect of averted vision, as sensors in the line of vision perceive light different from ones around the periphery. Averted vision (when you are using the corner of your eyes to see something) enables you to see more light in an object which is useful when observing any nebula or star cluster to tease out as much detail as possible.
A Binocular Target
If you have binoculars to hand, there is a lovely bright and compact nebula you can discover in the constellation of Sagitta.
To find the Dumbbell Nebula (M27), Look for the Summer Triangle comprising Altair, Deneb and Vega. On the western length of the triangle, nearly halfway between Altair and Deneb, lies the nebula.
In a dark sky it will appear like a small, puffy apparition among a rich field of stars. This planetary nebula, comprised of ejected gas from a dying star, is situated 1360 light years away.