New Zealand switched to summer time, that is we put our clocks forward one hour. We are seriously starting to think now about solar astronomy. As the fishhook of Maui sinks towards the western horizon, and with it the galactic centre, there are still many wonderful objects to see in the night sky. The Magellanic Clouds are still there and especially the Small Magellanic Cloud is good to observe after sunset. Grus, the Crane – famous constellation with double doubles is getting close to the Zenith this month, the Sun is in Virgo until November the 1st and Pisces lay on the horizon at sunset. Mercury, Venus and the Moon all get up close and personal just after sunset on 30 October. Mercury and Venus will be just under three degrees apart and the waxing crescent Moon will be just 8 degrees away from the pair of planets. Through a telescope you’ll see the three different phases of the different celestial bodies, with the Moon being just a slither, Mercury being 35% illuminated and Venus, nearly full at 94%. To achieve this configuration Venus is on the other side of the Sun to Earth’s position, with Mercury almost half way between. Observable comets are also in the Southern Sky, 289P/Blanpain and C/2018 W2 Africano at the Aquarius end of Pisces.
Make a plan and make it so!
Make an observing plan before you go out, we usually do make one, there’s a cool option in Sky Safari, which is an app we use a lot to do that. Although these days every time we go out observing we always carry a DSLR camera with us and a tripod to take wide field photographs of the night sky as well as whatever cameras we could get on a telescope. Mostly now is about astrophotography or drawing that is very exciting about observing.
What’s the Sun up to?
The reality is that the Sun does not spend an equal amount of time passing through the zodiacal constellations, for the simple reason that these constellations are different areas patches in the sky. So technically, this month, the Sun is in Virgo until the 1st of November when it moves into Libra and has been in Virgo since the 17th of September. Virgo is a really long constellation to transit.
What’s at Zenith?
Beautiful Sagittarius is at Zenith just after Sunset and then as the month progresses it’s replaced by other amazing constellations such as Microscopium, which is basically a rectangle, and then one of our favourite constellations, Grus towards the middle of the month – or later on in the evening, whichever you prefer. The cool thing about Grus, the Crane is that it has many double stars, it almost looks like a curved line, which is the imaginary tail that points us towards the Small Magellanic Cloud, which is in the neighbouring constellation, another bird, the Toucan.
The Royal stars were the guardians of the sky in approximately 3000 BCE during the time of the Ancient Persians in the area of modern-day Iran. The Persians believed that the sky was divided into four districts with each district being guarded by one of the four Royal Stars. The stars were believed to hold both good and evil power and the Persians looked upon them for guidance in scientific calculations of the sky, such as the calendar and lunar/solar cycles, and for predictions about the future.
In addition to that, another favourite of mine, Fomalhaut, is getting very close to Zenith this time of the year. I love Fomalhaut because when I was in the Northern Hemisphere, before I travelled here, it was the southernmost star that I could see, and it was said to show the passage south. It actually does if you know where to look. Fomalhaut is one of the Royal stars, along with Antares, Regulus and Aldebaran.
What’s on the Ecliptic?
The ecliptic is the part of the sky that holds the path of the Sun as we see it from here from Earth, and other than bright planets, it also hosts some bright stars. There’s Zubenelgenubi and Zubeneschamali in Libra getting close to the western horizon and then red giant Antares in Scorpius and a few of the stars in Sagittarius, that make the teapot. Capricornus has also some bright stars and it’s very characteristic shape of a golf flag. Then, this is kind of it with the bright stars, will have to wait until late in the night to see Taurus and Aldebaran, the other of the Royal Stars and last but not least, Regulus, in Leo will rise just before the Sun.
The Milky Way, Scorpius and Orion
The bulk of the Milky Way is on the Western horizon. The Galactic centre slowly going down sinking behind the Sun. The Southern Cross, which is also visually in the Milky Way, is doing its big descent as it dives towards the horizon, getting lower and lower each evening throughout the month, as seen after sunset. It is circumpolar so it never disappears from the Southern Sky but it means the lovely clusters and nebulae that you would have enjoyed in Spring and Winter have long gone from being in a favourable viewing position — they now compete with the horizon.
The other patch of the Milky Way that remains in a very good position for viewing is the area around Sagittarius and Scorpius with many globular clusters and nebulae (distant, celestial clouds) to look at. The highlights, for me, are the bright nebulae such M16 (the Eagle Nebula), Lagoon Nebula and the very photogenic Trifid Nebula. Ptolemy’s Cluster is a great naked eye object that is visible between the two constellations.
South Circumpolar Zone
Just after sunset, the Large Magellanic Cloud and the Southern Cross are close to the horizon where the Small Magellanic Cloud is in a good position to observe.
Wanna know more?
If you want to go hunting for comets in the Southern Sky you might be able to spot 289P/Blanpain. It starts the month at 10.2 magnitude so not very bright, but by the end of the month it will be 8.8, and quite close to the Helix nebula.
Another one worth having a look for is C/2018 W2 Africano which starts the month at its brightest, at the Aquarius end of Pisces. On Friday the 4 October this comet will get about degree from Neptune so a great opportunity to get a photo of both of these icy cold objects. The comet will be at magnitude 10 and Neptune at 7.8.
Another interesting comet that we might catch a glimpse of is P/2008 Y12 Soho. This one will be approaching closer and closer to the sun and can be found not far from Venus, so you’ll need a fantastic horizon and great conditions, it will brighten significantly as it gets near to the Sun, but that will also make it impossible to see.
The best time to see it will be at the beginning of the month when it is magnitude 4.4 about 4 degrees to the right of Mercury, and 21 degrees from the Sun so it should be high enough above the horizon and dark enough.
The Moon is full on the 14th October and the New Moon is on 28 October. At 11pm on the 17th October the Moon gets very close to Pluto, though at magnitude 14.4 it will be well and truly overshadowed by the -10 magnitude Moon, kind of an almost occultation that you wouldn’t be able to see easily anyway.
On the 5th October it is international observe the Moon night, so get out there with your telescopes, binoculars, or just your eyes and take a moment to appreciate the celestial body that gives our planet a handy tilt, tides and a day that’s 24 hours long, without the Moon we may not have been able to climb out of the primordial soup at all.
It’s a good time to see Mercury at the start of the month with it being a good 20 degrees from the Sun. Mercury should be easy to spot if you have a good Western horizon, just look for Venus, after sunset, almost on the horizon and then the next brightest, slightly orange thing above it is Mercury.
Jupiter is always amazing to view, though it’s starting to get a bit further away from us, as compared to a month ago. At the start of the month the gas giant will take up 36 arc seconds of your eyepiece but by the end of the month this will have reduced to just a bit more than 33 arc seconds. Jupiter sets about 1:23am at the start of the month and by the end it is setting at 11:48pm.
You will be able to see Europa cross the planet’s disk on the 3rd in the early evening as soon as the Sun goes down, followed by Io again at around 9pm. The next good one to watch is on the 10th at 7:15pm when Europa and then shortly followed by Io pass in front of Jupiter. Another one of these paired moons crossing starts at 10pm on the evening of the 18th as well. So there are plenty of opportunities to catch an eclipse on Jupiter this month.
Over the course of the month Saturn gets about 100 million kilometres further away but starts in a good position for viewing. Saturn is almost a month behind Jupiter with it setting at 1:20am at the end of the month, and setting at the start of the month at 3:10am.
Neptune and Uranus
Another planet that is worth taking a look at, though don’t expect to see much, is Neptune. This cold gas giant is over 4.3 billion kilometres away. It is so far away that it takes light from Neptune 4 hours to get to the Earth. You might be able to make out the hint of a disk, but at an apparent size of 2.4 arcseconds you may need to use a bit of imagination, though you will see the bluish hue of Neptune. You can find it by looking for the bright star Phi Aquarii in Aquarius and it’s about 40 arcminutes from that star.
Uranus is also worth looking at if you happen to be up quite late as it doesn’t rise until about 10pm at the start of the month and 7:35pm by the end of the month. This planet is a bit closer at 2.8 billion kilometres and its apparent size is 3.7 arcseconds, so you shouldn’t need to use too much imagination to see the greenish hue of its disk.
Happy Observe the Moon Night on the 5th October!