Each Monday I pick out the northern hemisphere’s celestial highlights (mid-northern latitudes) for the week ahead, but be sure to check my main feed for more in-depth articles on stargazing, astronomy, eclipses and more.
The Night Sky This Week: August 28-September 3, 2023
“Once in a blue moon” is this week! Although it’s just a name (no, the moon will not look blue!), this week sees August’s second full moon—one definition of the phrase. It happens every 2.7 years, so it’s not rare, though this year it’s worth seeing for two reasons:
- A full moon as it appears on the horizon looking orange is always a drop-dead gorgeous sight.
- Saturn at its biggest, brightest and best will shine alongside the “Super Blue Moon.”
These are two reasons to get outside looking up this week—but there are many others:
Monday, August 28: Uranus Retrograde
From today through January 27, 2024, Uranus will be in a period of apparent retrograde motion while in the constellation Taurus—appearing to go backwards in the sky. Earth orbits the sun much faster than the outer planets, so occasionally overtakes them. They then appear to be moving backwards for a short time—much like if you overtake a vehicle on the highway.
Since Uranus takes 84 years to orbit the sun its “backwards” phase appears to last many months. It’s all and only a matter of perspective and has no significance to humans.
Wednesday, August 30: A ‘Super Blue Moon’ Rises Close To Saturn
The third and final full moon of summer in the northern hemisphere will be a “Super Blue Moon” because it’s the second full moon in a calendar month, something that is bound to happen every few years because the moon takes 29 days to orbit the Earth.
It’s also the closest full moon to Earth in 2023—so the year’s best “supermoon.” It will turn full while 357,344 km from Earth and be the biggest, brightest full Moon of the year.
It will look its best at moonrise on two successive evenings, Wednesday, August 30 and Thursday, August 31. Look out for Saturn, which will be just 2.5º from the full moon as it rises.
Thursday, August 31: Summer Triangle
Despite the presence of strong moonlight you will be able to see this signpost of summer if you’re above the equator. Comprised of three bright stars—Vega, Deneb and Altair—the “Summer Triangle” ‘is an asterism (not a constellation) that’s overhead in September.
Sunday, September 3: Delphinus, ‘The Dolphin’ and Sagitta, ‘The Arrow’
Since you know where the “Summer Triangle” is you can start to look for smaller shapes of stars around it. To the left of a line between Deneb and Altair is the sparkling small constellation of Delphinus, “The Dolphin” while just above Altair is tiny Sagitta “The Arrow.”
Saturday, September 2: the Great Hercules Globular Cluster
With the moon now rising late at night, it’s time to find a telescope and point it at one of the most amazing sights of the northern hemisphere’s summer skies. Aim it at the Great Hercules Globular Cluster (M13) and you’ll see a fuzzy patch that’s the collective light from 300,000 ancient stars about 25,000 light-years distant.
Object of The Week: ‘Super Blue Moon’
This week sees the rise of 2023’s third “supermoon,” which a calendar quirk leaves it without a name—and hence a “blue moon.” There are four supermoons in 2023—July 3, August 2, August 31 and September 29—and they occur because the moon’s orbit of Earth is slightly elliptical.
In every orbit of Earth the moon comes to a perigee (closest) and most distant (apogee), which occur every month 14 days apart. When perigee happens on or close to a full moon they tend to be called “supermoons.”
Stargazing Tip Of The Week: Be Patient
The stars are not going anywhere. When you first stargaze, you’ll be disoriented and confused, likely for many months. Don’t worry at all about that. Take your time to learn one constellation after another, making sure every time you go stargazing you do some quick revision by identifying the constellations you have previously learned.
Over time you’ll build-up an immense amount of knowledge. The night sky can be navigated and it can be known, just like a map of the continents and countries on Earth, but it takes time.
Times and dates given apply to mid-northern latitudes. For the most accurate location-specific information consult online planetariums like Stellarium and The Sky Live. Check planet-rise/planet-set, sunrise/sunset and moonrise/moonset times for where you are.
Wishing you clear skies and wide eyes.