Find out what to go out and look at this month

Planets:

Mercury will disappear into the Sun’s glare after three nights and will reappear in the early morning at the end of the month, but it’ll be hard to see due to it being very low on the horizon and close to the Sun’s glare. Mercury will reach its greatest elongation in the East on the 25th of October and it’ll begin to make its way back towards the Sun. Venus can also be found in the Western early evening sky in the constellation of Libra (The Scales) at the start of the month and through October, it will move through the constellation of Scorpius (The Scorpion) and into the constellation of Ophiuchus (The Serpent-Bearer). Venus will reach its greatest elongation in the West on the 30th of October and it’ll begin to make its way back towards the Sun.

Jupiter and Saturn can be found in the high in the evening in the constellation of Capricornus (The Sea-Goat). At the beginning of the month, Jupiter will set at 04:00 am (AWST) and Saturn will at 03:08 am (AWST). By the end of the month, Jupiter will set at 02:01 am (AWST) and Saturn will at 01:11 am (AWST)

Uranus can be found in the evening in the constellation of Aries (The Ram). At the beginning of October, Uranus will rise at 10:59 pm (AWST) and by the end of the month, it’ll rise at 09:02 pm (AWST). Neptune will be viewable as well in the evening between the constellation of Aquarius and the constellation of Pisces (The Fish). At the start of October, Neptune will set at 05:16 am (AWST) and by the end of the month, it’ll set at 03:20 am (AWST).

Mercury's greatest elongation in the East on the morning of 25/10/2021. Image Credit: Stellarium
Venus on the 15/10/21 at 08:00 pm. Image Credit: Stellarium
Venus's greatest elongation in the West on the evening of 30/10/2021. Image Credit: Stellarium
Jupiter, Saturn, Uranus and Neptune on the 15/10/21 at 09:00 pm. Image Credit: Stellarium

Conjunctions and Occultations:

Conjunctions involve object(s) in the Solar System and/or more distant objects, such as a star. It’s an apparent phenomenon in which multiple objects which aren’t close together appear close in the sky and it’s caused by the observer’s perspective. An occultation is an event that occurs when one object is hidden by another object that passes between it and the observer.

  • 01/10/21 – Conjunction of the Moon, Castor and Pollux (Where to look)
  • 09/10/21 – Alignment of the Moon, Venus and Antares (Where to look)
  • 10/10/21 – Conjunction of the Moon, Venus and Antares (Where to look)
  • 13/10/21 – Alignment of the Moon, Jupiter and Saturn (Where to look)
  • 14/10/21 – Conjunction of the Moon and Saturn (Where to look)
  • 15/10/21 – Conjunction of the Moon and Jupiter (Where to look)
  • 16/10/21 – Conjunction of the Venus and Antares (Where to look)
  • 28/10/21 – Conjunction of the Moon, Castor and Pollux (Where to look)

Astronomical Events This Month:

The Orionids Meteor Shower:

The Orionids Meteor Shower has been observed for at least 200 years now and they’re caused by The Earth flying through the debris leftover from Comet Halley’s tail. They’ll appear to be coming from the Orion constellation which is where the meteor shower gets its name from.

The debris field started hitting The Earth around the 2nd of October and it’ll finish up towards the 7th of November. The meteor shower will peak on the night of the 21st and 22nd of October, and you should expect to see up to 5 meteors per hour this year as the Moon is near the Full Moon phase so it’ll affect how many we’ll see. The best time to view the Orionids which is between 02:00 am and 05:00 am.

If you do get up at those ungodly hours to look at the meteor shower, you need to look directly east around midnight and then towards the North as it gets closer to sunrise.

The Orionids on the 22/10/21 at 02:00 am. Image Credit: Stellarium
A composite of the Orionids meteor shower. Image Credit: Slooh Observatory

Things to Look at This Month:

Albireo:

Albireo is a double star that is 390 light-years away from us located in the constellation Cygnus. Albireo is the ‘beak star’ in Cygnus the Swan. The origin of the name is through several mistranslations between Greek, Arabic and Latin. It is a good wide double star with strong colour contrast, possibly the best available to modest telescopes. It is low in the North and only available for a few months of the year during the late winter and spring. The primary star is yellow/amber in colour whilst its companion is blue/green.

The primary star is, in fact, a close binary also, however, it is too close and faint to detect without very large telescopes and excellent observing conditions. The stars revolve around one another in about ~100 000 years. The primary star is ~5 times the mass and ~1 200 times brighter than the sun but with a cooler surface temperature of ~4 100 K. The secondary star is ~3.2 times the mass and ~230 times the brightness of the sun with a surface temperature of ~12 000 K.

Albireo on the 15/10/21 at 9:00 pm. Image Credit: Stellarium
Albireo. Image Credit: Palomar Observatory/STScI/WikiSky
The Sculptor Galaxy:

The Sculptor or the Silver Coin Galaxy (NGC 253) is a barred galaxy in the Sculptor constellation roughly 67,000 light-years in width. It was discovered by Caroline Herschel in 1783, whilst carrying out a comet search. It is one of the group of Sculptor galaxies, which is grouped around the south galactic pole (These galaxies are sometimes named “The South Polar Group”). The Sculptor group may be the next closest group of galaxies beyond our Local Group, located about 11.5 million light-years from Earth.

Often called a Starburst galaxy because it has a large number of stellar nurseries in which many hot young blue stars are being formed. This is due as a result of a collision with a dwarf galaxy approximately 200 million years ago. The process of star formation and subsequent explosion as supernovae occurs at an unusually high rate of star birth.

These young stars emit radiation that causes the hydrogen gas to glow brightly in pink. NGC253 has many Wolf Rayet stars (WR stars start off as hot massive stars, around x20 solar masses, that rapidly lose mass by blowing their hydrogen envelope away in the form of high-velocity stellar winds.) The Silver Coin Galaxy also has a large proportion of dust, although not in clearly defined lanes, such as those found in the Milky Way Galaxy.

With an apparent magnitude of 7.2, it’s the second easiest galaxy to see after Andromeda and not including the Milky Way’s two satellite galaxies (The Large and Small Magellanic Clouds). With good viewing conditions, it can be seen with binoculars with a long axis ~2/3 of the full moon.

Sculptor Galaxy on the 15/10/21 at 09:00 pm. Image Credit: Stellarium
Sculptor Galaxy - Image Credit & Copyright: Mike O'Day
Tarantula Nebula:

The Tarantula Nebula is an Emission Nebula that isn’t even located in our galaxy, but in one of our galaxies satellite galaxies, the Large Magellanic Cloud. The Nebula is some 160,000 light-years away from our Solar System and is 300 light-years across. This Nebula is an extremely luminous object, its luminosity is so great that if it were as close to Earth as the Orion Nebula, the Tarantula Nebula would cast shadows and take up 60% of the horizon. It’s is the most active starburst region known in the Local Group of galaxies, this is because the nebula resides on the leading edge of the Large Magellanic Cloud where ram pressure is stripping, and the compression of the interstellar medium likely resulting from this, is at a maximum.

Tarantula Nebula on the 15/10/21 at 09:00 pm. Image Credit: Stellarium
Tarantula Nebula. Image Credit: Peter Ward (Barden Ridge Observatory)
47 Tucanae:

47 Tucanae or NGC 104 is the second-largest and second brightest globular cluster in Milky Way. The Globular cluster is 16,000 light-years away from us and is located in the constellation Tucana (Named after the Tucan bird) and it’s a naked eye ‘star’ and visible in binoculars as a ‘fuzzy blob’. Omega Centauri contains at least 1 – 2 million stars and the cluster has a diameter of roughly 120 light-years and the stars are roughly 10 billion years old. The average distance between the stars in the centre of the cluster is around 10% of a light-year or more than 100 times the diameter of our solar system. In February 2017, indirect evidence for a likely intermediate-mass black hole in 47 Tucanae was announced.

47 Tucanae on the 15/10/21 at 09:00 pm. Image Credit: Stellarium
47 Tucanae. Image Credit & Copyright: Mike O'Day

Phases Of The Moon:

October 2021 Moon phases