Astronomy guide to the night sky October 2025
With the Newbury Astronomical Society
The chart above shows the night sky at 21:00 on 15th October 2025
(Click on the image above to enlarge and click away from the image to return here)
The chart above shows the night sky looking south at about 22:00 BST on 15th October. West is to the right and east to the left. The point in the sky directly overhead is known as the Zenith, it is shown (in red) at the upper centre of the chart. The curved brown line across the sky at the bottom is the Ecliptic or Zodiac. This is the imaginary line along which the Sun, Moon and planets appear to move across the sky. The brightest stars often appear to form a group or recognisable pattern that we join ‘dot to dot’. We call these ‘Constellations’ marked in blue above.
Constellations through which the ecliptic passes this month are: Sagittarius (the Archer), Capricornus (the Goat), Aquarius (the Water Carrier), Pisces (the Fishes), Aires (the Ram) and Taurus (the Bull).
Prominent in the southern sky is the Summer Triangle that dominates the Summer Sky and is labelled on the chart above. The term Summer Triangle was first suggested by Sir Patrick Moore and is defined by three obvious bright stars: Deneb in the constellation of Cygnus, Vega in Lyra, and Altair in Aquila. The Milky Way (our Galaxy) flows through the Summer Triangle and passes through Aquila and Cygnus. As the Summer Triangle is so easy to find it is very useful to use as a starting place for finding our way around the night sky.
To the west (right) of the Summer Triangle is the constellation of Hercules (the Strong Man). Hercules has a distinctive distorted square shape, at its centre, called the ‘Keystone’. This is due to its resemblance to the centre stone of an arch or bridge. The jewel of Hercules is without doubt the Great Globular Cluster, Messier 13 (M13) that can be found in the western vertical imaginary line forming the ‘Keystone’.
It is just visible using a good pair of 9 x 50 binoculars. The spherical cluster, of about a million stars can be seen using a 90mm f10 telescope but will look even more impressive when using a larger telescope.
To the East (left) of the Summer Triangle is the constellation of Pegasus (the Winged Horse). The main feature of Pegasus is the square formed by the four brightest stars. This asterism (shape) is known as the Great Square of Pegasus. The square is larger than might be expected but once found is easier to find again.
The square can be used to judge the seeing condition of the night sky. Under perfect conditions, about ten stars can be seen inside the square, this would indicate a very good night for observing. If three to five stars can be seen, then conditions will still be good. If fewer or none can be seen, then stick to looking at the Moon or planets. There is a very nice Globular cluster in Pegasus that is known as Messier 15 (M15) and is a lovely sight to see in a medium to large telescope.
From the top (north) left (east) star of the Great Square of Pegasus is the star called Alpheratz. Although Alpheratz is obviously part of the Great Square of Pegasus it is allocated to the ‘joined’ constellation of Andromeda (the mythical princess). The two constellations are share and are joined at the star Alpheratz. Andromeda has the form of an elongated ‘>’ shape emanating from Alpheratz.
If we trace the lower (and brighter) ‘arm of the ‘>’ shape to the second star of three stars in the line ‘called Mirach’ we will find two stars above. Using binoculars, to the right of Mirach’ a small ‘fuzzy’ patch of light can be found this is the Messier 31 (M31) the Great Galaxy in Andromeda. Messier 31 is beautiful to see using a telescope and is described in more detail on pages 4 and 6.
The Ecliptic is still low in the sky during the Autumn months so the Moon and planets appear close to the southern horizon. Saturn is well placed in the south-east and Jupiter will be moving into the early evening sky and will be at its best for observation later in the next few months. The thick, murky and turbulent air above the horizon may cause the planets to appear quite unsteady.
WHERE TO FIND THE PLANETS THIS MONTH
MERCURY is the smallest planet and closest to the Sun. It appears close to the Sun this month so it is not observable.
VENUS is close to the eastern horizon as the Sun rises at about 07:00. It is moving back towards the Sun and into its Superior Conjunction on 8th January 2026. It is getting smaller in diameter as it moves further from us and passes behind the Sun as we see it.
MARS is moving further away from us as we on Earth move faster along our orbit and leaving Mars behind. It is close to the Sun this month, just above the horizon at sunset.
JUPITER Is now starting to move into the evening sky and rises over the eastern horizon at about 23:00. It will not be observable until later into the night at about midnight.
SATURN will be best observed later in the evening when it is the southern sky. Saturn will be due south at about 23:00 when it will be at its best position for observing. Neptune is close by this year. We are looking at Saturn’s ring system edge on at the moment so it appears almost like just a line across the planet.
URANUS rises over the eastern horizon about 19:20 but is best observed at about midnight when it has moved into the south-east and is positioned higher in the sky. Uranus can be found using binoculars with a rating of 8 x 50 to 10 x 50 as a slightly blue ‘fuzzy’ looking star. A modest beginner’s telescope 90mm x 1000mm focal length will show Uranus as a small blue disc.
NEPTUNE is positioned close to Saturn so that will make it slightly easier to find. It is located a few degrees above and to the east (left) of Saturn. It may just be identified using a good 9 x 50 binocular but will need a telescope to see as a small blue disc.
To see a full version of this article and a guide to the night sky with charts, read the monthly magazine on the Newbury Astronomical Society website at: Magazine October 2025
For details and directions visit the Newbury Astronomical Society website at: Home – Newbury Astronomical Society
Our next meeting will be at Stockcross Village Hall on Wednesday 15th September 2025, from 7pm until 9pm.
