All information presented here is taken from my book Nightscenes 2021 (pt1)

There will be no printed edition for 2021 but a pdf/kindle version for July to December is now available from the nightscenes web page.

Click on the monthly image to get a larger high resolution view of the night sky set for 53° N (Horncastle, England) but is usable for the UK and Eire.  All charts are set for the 1st of the month at 22:00 GMT (10pm) and can be used on the other dates and times shown in each corner of the chart.

August 2021

Solar System quick summary

Some charts & images in the text can also be clicked to give a larger view.

Venus lingers low over in the western evening twilight all month. Vesta also hangs on in the evenings in Virgo as the evening get darker. Saturn comes to opposition on the 2nd followed by Jupiter on the 20th and are becoming well placed for evening viewing. Neptune is up next, later in the night, followed by Uranus, both also benefiting from the nights slowly drawing in. Last week of August dwarf planet, Ceres begins to pass under the Hyades star cluster in the morning sky. Mercury and Mars are lost in the solar glare all month. August has one of the years best meteor showers, the Perseids on the 12th with the moon in the early evening sky so a good year to view them once the moon has set.

Main events

Venus! Yes, we haven’t got rid of it yet in the evening twilight as it spends the month drifting along the western horizon. The key to its lasting visibility, despite its low position compared with the horizon, is that it is bright (mag -3.9) and the evenings are drawing in and the chart is set for ~ 45 minutes after sunset. The crescent moon joins in on the 10th and 11th as shown above with the moon shown twice normal scale for extra clarity. Venus will linger for a while yet like this, so keep looking out for it.

Technically Venus is no longer the only major planet visible in the evenings as Saturn, then Jupiter come to opposition this month. Saturn reaches it first on August 2nd and means Saturn rises as the sun sets and sets as the sun rises so it literally is opposite the sun in the sky. It also means that the planet is visible all night becoming steadily better placed for viewing in the evenings over the coming months. Saturn is magnitude 0.2 and so a naked eye object. Large binoculars will show it appears slightly odd and elongated and this is the effect of the ring system which are better seen when using a telescope.

Saturn’s main fame is the ring system which makes it look almost as big as Jupiter, yet the actual disk is smaller due to it being almost twice as far from us as the ‘King’ of the planets. On the planets disk look out for a North Polar ‘Hood’ and for a subtle dusky belt crossing the disk. The rings give Saturn its unique visual appearance in a  telescope so look to see if you can spot the gap in the rings. This is the Cassini Division that separates the outer ‘A’ ring from the brighter and larger ‘B’ ring. It is also possible to note the shadow of the planet on the rings if you are careful with your studies.  Finally, in small telescopes and large binoculars you may spot Saturn’s largest moon, Titan so check out the details of where it will be in the chart below.

In the meantime Jupiter reaches opposition on August 20th so 18 days later than Saturn showing it lies further along the ecliptic. Being bigger and closer than Saturn, Jupiter shows more detail in a telescope but if you use binoculars you may also be able to spot Jupiter's Galilean moons, the four were discovered by Galileo in 1610 AD. Small telescopes will show them better as in the view below taken by the author.

A telescope will also begin to show detail on the planet and the main features are shown at below. The GRS appears to be shrinking slowly so if you see it then give yourself a pat on the back. The two main equatorial belts are usually the most prominent but with continued study other subtle details may be glimpsed if conditions are right.

The almost full moon joins both planets as shown below when it will lie below Saturn on the 20th, forming a triangle with Jupiter and Saturn on the 21st then Full moon lies to the lower left of Jupiter on the 22nd. The chart is set for 10pm so a convenient time to view for most!

We haven’t quite finished with Jupiter yet as it has a second close pass north of the star iota Aquarii (mag 4.2 and shown on the above chart) on August 3rd when it is in conjunction but remains close to the star for a couple of days before moving away. With Jupiter at mag -2.8 you won’t get them mixed up!

We nip back to the start of the month and in the morning sky around 3am we find the slightly less than half phase moon just south of Uranus (above). Next morning the moon lies to the lower right of M45, the Pleiades star cluster whilst on the 3rd it lies above the orange star, Aldebaran before ending this run on the 4th between the horns of Taurus. For the moon to spend three sessions in one constellation hints that Taurus is quite large compared with some in the sky.


With the moon in Taurus on the 2nd & 3rd it suggests this might repeat at the end of the month and it sort of does as the moon lies between M45 and Aldebaran on the 30th. In fact it is the Last Quarter Moon but unlike the chart at right the moonlight will drown out a lot of the stars for the naked eye view. The Hyades star cluster is also always worth looking at both naked eye and in binoculars as an added attraction.

A fainter target than normal grabs our attention as Dwarf planet Ceres begins to pass south of the Hyades star cluster. Our chart above shows it in the mornings at 3am from August 15th to September 30th with August 31st also marked. Ceres will need binoculars or a telescope to spot but astrophotographers might want to image a sequence showing the movement as it glides under the cluster. Ceres is magnitude 8.9 on August 15th rising steadily to mag 8.3 by the end of September.

Our final target for August is multiple as it is one of the best meteor showers for the year, the Perseids. The good news is that the moon is new on the 8th so with the peak of the Perseids on the 12th the moon will be in the early evening sky setting shortly after 10pm. It will therefore be dark skies for the rest of the night when the showers radiant will climb higher in the NE sky and become better placed to view. The radiant is shown on the main all sky monthly chart and is so called as the meteors will appear to ‘radiate’ out from a point in the sky (the radiant). The longest streaks will be further from the radiant so we often say look roughly 45 degrees from the radiant's position in the sky for hopefully the longest meteor streaks. Why not make an event of it and invite the neighbours round if life has returned to normal…

Also look out for the following:

   5th   Crescent moon lies close to M35 star cluster (morning)

   6th   Crescent moon lies to the right of and forms triangle with Castor  and Pollux (morning)

   8th   Vesta lies north of Porrima (evening twilight)

12th   Crescent moon lies to left of Porrima (evening twilight)

13th   Moon lies above left of Spica (evening twilight)

14th   Moon lies to right of Alpha Librae (evening)

16th   Moon lies above Antares (evening)

23rd   Moon forms triangle with Neptune and Psi Aquarii (evening)

24th   Venus lies below Porrima in bright evening twilight

28th   Moon forms triangle with Mu Ceti and Uranus (morning)

Clear skies, happy sky watching and stay safe!


Webmaster  © Paul L Money 2021

The UK & Ireland Night Sky for 2020