October 2020 What’s Up!

Week of 26th October

• Astronomical twilight ends at 18:42 UT at the beginning of the week and at 18:33 UT by the end of the week
• Mars continues its journey westwards across our night sky, shining brightly at mag -2.3. Use binoculars or a telescope to observe surface features on the Red Planet. On Thursday it will be in conjunction with the Moon, separated by only 8°
• Uranus reaches opposition on Saturday. It will be 18.79 AU from Earth, about 2.8 billion km away. At mag +5.7 and 3.8 arcsec, it is best observed through a telescope. Due to the proximity of the Full Moon on Saturday, it will be easier to spot the planet a day or two before or after opposition
• The Moon will be Full on Saturday, the Hunter’s Moon. This is the second Full Moon of the month, making it known as a Blue Moon, though it won’t appear tinged blue! This use of the term ‘Blue Moon’ is a twentieth century custom that started in 1946. Historically the term was used to name a fourth Full Moon of a season, where normally only three Full Moons appear per season and have traditional names
• The Sun currently has one active region AR 2776, which contains 11 sunspots
• There are no visible ISS evening passes this week

Week of 19th October

• Astronomical twilight ends at 19:56 BST at the beginning of the week and at 18:44 GMT by the end of the week
• British Summer Time ends on Sunday, when the clocks go back one hour at 02:00 BST to become 01:00 GMT
• Mars continues to be the highlight of our evening sky, shining brightly at mag -2.5. It rises at 18:00 BST and reaches its highest elevation of 43° around midnight
• Jupiter (-2.2) and Saturn (0.5) are still visible, but have set by about 22:30 BST
• The Orionid meteor shower peaks on Wednesday. It can produce around 15 to 20 meteors an hour. The parent body that creates this meteor shower has been identified as comet 1P/Halley
• The Moon will be First Quarter on Friday. On Thursday and Friday evenings it will make a close approach to Jupiter and Saturn
• The Sun currently has one active region AR 2776, which contains around 15 sunspots
• There are no visible ISS evening passes this week

Week of 12th October

• Astronomical twilight ends at 20:10 BST at the beginning of the week and at 19:58 BST by the end of the week
• At 00:18 BST on Wednesday, Mars will be at opposition, situated directly opposite the Sun. This is the best time this decade to observe Mars as it will be at its largest and brightest in our night sky. It will be about 0.42 AU away, shining at a magnitude of -2.6 and its disc will measure 22.3 arcseconds in diameter. It is at its highest point in the sky at around 01:00 BST, when it will be at an altitude of about 43°. Get out there and observe Mars, ideally through binoculars or a telescope; can you see any dark surface feature details?
• The Moon will be New on Friday
• The Sun currently has two sunspots, active regions AR 2774 and AR 2775. Their polarity and high southerly latitude identify them as members of the new Solar Cycle 25
• There are no visible ISS evening passes this week

Week of 5th October

• Astronomical twilight ends at 20:26 BST at the beginning of the week and at 20:12 BST by the end of the week
• Mars reaches perigee on Tuesday, when it will be at the closest point to Earth in its orbit, around 62 million km. This makes Mars appear largest and brightest in our sky, at magnitude -2.6 with an apparent size of 22.6 arc seconds. It is moving ever closer to opposition, which occurs on 14th October
• The Moon will be Last Quarter on Saturday
• The Sun currently has no visible sunspots. This spotless stretch is 8 days
• There are no visible ISS evening passes this week