What Can I See in the Sky in August 2021?

August is the month that darkness returns. For the sky to be completely dark, the Sun must get at least 18 degrees below the horizon. On 1st August this happens at 00:46 and lasts until 02:24, giving 1 hour 42 mins of darkness. By the end of August this has stretched to 5 hours 48 mins. August is also famous for the Perseid meteor shower which you can read more about below. You may still spot noctilucent clouds. They can be seen some evenings shining in the north after sunset and before sunrise but it is at the end of the season for them. I have another post about noctilucent clouds and the link is below:


Sun and Moon

DateSunrise (Irish Time)Sunset (Irish Time)
Sunrise and sunset times
Moon PhaseDate
New Moon08/08/2021
First quarter15/08/2021
Full Moon22/08/2021
Third Quarter30/08/2021
Moon phases



Make sure the Sun has set before looking for Mercury. It will be very hard to see this month. It might be possible to catch a glimpse of it after sunrise.


Venus is an evening planet in August but is not well positioned. It will set around 1 hour after sunset and will be very low in the west.


Mars isn’t visible this month.


Jupiter is visible this month in south. It will already be above the horizon as the sky darkens and is very bright. It will be unmistakable as it will far outshine anything else in that area. If you have a small telescope or even binoculars, you should be able to pick out some of the moons that are orbiting the planet. The four that will be visible in a small telescope are Europa, Ganymede, Calisto and Io. They will look like tiny stars in a line each side of the planet. They will appear to change position during the night. If you don’t see all of them that means one of them is either in front of the planet or behind it.


Saturn is visible close to Jupiter, it is also above the horizon before darkness falls. It will be a lot dimmer than Jupiter but should still stand out amongst the other stars in the area. Look for it, west of Jupiter, in the south west. If you have a small telescope, you should be able to see the rings which is a particularly nice sight.

Perseid Meteor Shower

The Perseid meteor shower peak happens in early August each year. It is quite a reliable shower. Normally, if the clouds clear, the weather is warm enough so that you can go outside and watch them in relative comfort. This year the peak happens between 20.00 and 23.00 (Irish time) on the 12th August. Therefore, the best time to watch them is on the nights of August 12th and August 13th. The Moon sets at 22.20 on August 12th which means the conditions are particularly good this year. I would really encourage you to get out for a look if the sky is clear.

To watch the Perseids, make yourself comfortable. A sun lounger or hammock is ideal. Also make sure you are warm, a sleeping bag can be very useful for this, as are hot drinks such as tea or hot chocolate! You can look in any direction, but try to look away from any lights around to ensure you aren’t blinded. The best time to watch is between 23.00 on the 12th and 3.30am on the 13th. Meteor showers tend to be best after midnight, as the Earth is facing into the stream of dust causing the meteors.

Stars and Constellations

Sky chart for August 2020 00:00 15/08/2021 credit: Heavens above

The above sky chart is for 00:00 on 15/08/2021. You can click on the chart to open a new tab and bring you to Heavens Above. On this website you can generate a custom chart for the time and date you wish. The spring constellations of Leo (the lion), Bootes (the herdsman) and Virgo (the virgin) are now setting in the west.

High overhead are Cygnus (the swan), Lyra (the liar) and Aquila (the eagle). The brightest stars in these constellations are Deneb, Vega and Altair and they make up the Summer Triangle and is a true sign that we are in the middle of Summer. The misty path of the Milky Way also runs through this area of sky.

In the south at this time of year, is the constellation of Scorpius (the scorpion). This is the direction of the centre of our galaxy, the Milky Way. It never rises very high in the sky from Ireland, but if you look in the direction you should be able to make out that it is almost misty or milky with stars.

The autumn constellations of Pegasus, Pisces and Perseus are rising in the east at this time.

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