All information presented here is taken from my book Nightscenes 2021 (pt2)

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.

September 2021

Solar System quick summary

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

Venus refuses to leave the early evening twilight and hugs the horizon towards the West to SW all month. Jupiter and Saturn are in effect the main planets of the mid to late evening skies with Neptune and Uranus not far behind. Neptune is at opposition on the 14th becoming viewable all night.  We have two early morning occultation's of stars by the moon at the start of the month, Mebsuta and Kappa Geminorum.  Ceres continues moving under the Hyades and Aldebaran. Minor world Pallas is at opposition on the 11th. Mars is too close to the sun whilst Mercury is also lost in the solar glare so both are not visible.

Main events

Venus stubbornly refuses to depart the evening twilight as it appears to move along the horizon moving from West to SW during the month. It remains low but visible this time of year because the ecliptic lies at a shallow angle to the horizon stopping Venus climbing higher. At the same time the motion of Venus compared with the sun along the ecliptic keeps it one step ahead for now. View roughly half hour to 45 minutes after sunset and on the 5th Venus lies above Spica. How easy it will be to spot the star is difficult to judge but at least we have a bright planet to at least guide us as Spica is mag 1 compared with Venus at -4! Spica rapidly drops out of view then on September 9th the slim crescent moon lies to the  upper right of Venus then to the upper left on the next evening.

Once the sky becomes darker then over towards the southern horizon we find the two largest gas giant planets of Saturn and Jupiter. The view above is set for September 10th with Venus and the Moon at right and Jupiter and Saturn on the left. Neptune is also just above the horizon but not shown above. You can see there is quite a gap between Venus and Saturn!  

Jupiter lies 1.5 degrees north of Delta Capricorni on the 12th (above) then lies just south of 45 Cap on the 19th/20th as the planet retrogrades against the stars. Jupiter's moons have been omitted from the chart to avoid confusion.

Saturn too is retrograding and passes just over a degree south of Upsilon Cap on the 8th as an added bonus, the star is marked on the chart above. The moon lies below right of Saturn on the 16th, forms a triangle with the ringed planet and Jupiter the next evening then lies to the lower left of Jupiter on the 18th as shown above looking SSE at around 9pm.

Whilst Jupiter and Saturn get all the limelight in the evenings skies they are no longer the only gas giant planets on view in the evenings as Neptune now reaches opposition on the 14th. Although much fainter than the others it has the advantage of being higher up the ecliptic and so is better placed to view as it climbs higher into the sky compared with Jupiter & Saturn.

The chart above shows Neptune’s path from Sept 1st until Oct 31st.  It is magnitude 7.8 so good to spot in binoculars or small telescopes. The diamond shaped group of stars are slightly brighter than Neptune between mags 6.2 and 7.20 making a convenient guide to spotting the official last planet in our solar system. Indeed Neptune glides by close to the brightest star of the group from September 22nd to 24th as a bonus. The left star of the diamond is HIP 116402 which Neptune passed close to back in July.

We have two early morning occultation's of bright stars by the moon near the start of September. On the 2nd look low down towards the NE shortly after moonrise around 1am for a star to the left of the moon and close to it. This is Epsilon Geminorum or Mebsuta and occultation occurs around 1am +/- a few minutes depending on where you are in the country. Reappearance is about fifty minutes later at the dark limb so always begin looking a little earlier so you are not caught out.

The next occultation is the next morning when Kappa Geminorum is occulted. The moon will be higher in the morning sky as the occultation takes place around 3;40am but again always begin earlier and watch the moon approach the star. Reappearance is just under an hour later so again allow more time so you don’t miss it. Times will vary for both occultation's depending on where you are in the UK so bear that in mind. Binoculars may allow you to see both events but for best results a telescope is far better.

Minor planet 2 Pallas is faint at mag 8.8 on Sept 1st where it lies south of Gamma Piscium. It is at opposition on September 11th and will be mag 8.6 so it will require binoculars or a telescope to spot. Another minor planet, 7 Iris lies close to the cluster M35 from Sept 2nd to 4th  and is faint at mag 9.7 so requiring a telescope.

Finally, Ceres is still passing under the Hyades star cluster as shown in the chart above. It lies south of Theta 2 Taurii on the 2nd and is magnitude 8.7 so a binocular object but large binoculars or a telescope would be better. It then passes south of the bright naked eye star Aldebaran, Alpha Taurii on the 11th /12th then on the 17th lies very close to Sigma 1 Tauri when it will have brightened a little to mag 8.5, before leaving the cluster behind, for now. During November it will pass very close to Aldebaran and then through the heart of the Hyades so one to watch out for and keep track of.  

Also look out for the following:

  1st   Aurigids meteor shower peak (early morning with moonlight)

  4th   Crescent Moon lies above Beehive cluster (morning)

  6th   Slim crescent Moon lies to the left of Regulus in bright morning twilight

12th   Crescent moon lies between Graffias and Antares (evening twilight)

13th   First Quarter Moon lies near Theta Ophiuchi (evening)

14th   Moon lies lower right of Kaus Borealis (evening)

19th   Moon forms a line with Psi Aquarii and Neptune (evening)

20th   Full moon lies in Pisces to left of Neptune (evening)

24th   Moon lies below Uranus (evening)

25th   Moon lies below M45 (evening)

26th   Moon lies to upper left of Hyades and Aldebaran (evening)

29th   Last Quarter Moon lies near to Mebsuta in Gemini (morning)

30th   Moon forms triangle with Castor and Pollux (morning)

Clear skies, happy sky watching and stay safe!


Webmaster  © Paul L Money 2021

The UK & Ireland Night Sky for 2020


The Autumnal Equinox occurs on September 22nd  at 19:21 GMT (20:21 BST). Autumn officially begins in the N. Hemisphere whilst Spring begins in the S. Hemisphere.