Some Telescope Tips, a Meagre Moon, and Mars Helps See the Sea-Goat!
Leonids Meteor Shower
We’ve now entered meteor shower season! Over the next few months, we’ll experience a wave of several showers. The Leonids Meteor Shower, which is derived from material dropped by repeated past passages of Comet 55P/Tempel-Tuttle, is now ramping up towards its peak night on November 17. The maximum number of Leonids will appear before dawn local time, because that is when the sky overhead will be plowing directly into the cloud of particles that produce the shower.
The meteors can appear anywhere in a dark sky, but true Leonids will be travelling in a direction away from a location (the radiant) just above the stars that form the head of Leo (the Lion). You can watch for meteors in the evening, too — but many of them will be hidden from view below the Earth’s horizon. This week’s meagre moon will keep the sky darker — ideal for seeing fainter meteors.
To see the most meteors, find a wide-open dark location, preferably away from light polluted skies, and just look up with your unaided eyes. Binoculars and telescopes are not useful for meteors — their field of view are too narrow. If the peak night is cloudy, several nights on either side will be almost as good. Happy hunting!
For North Americans, turning the clocks back an hour this weekend will mean that evening stargazing can start early. So bring out your telescope after dinner and treat the kids to views of Mars and Saturn, and the extra stars this week’s moonless nights we’ll offer. For best results, put your telescope and eyepieces outside an hour or two before you plan to observe. That will let the air trapped inside acclimate to match the cooler temperatures outside.
To avoid frost forming, keep all the glass surfaces’ (lenses and mirrors) covers on until the viewing starts, and put the caps back on before you carry the telescope back inside. If you have a case or bag for your telescope, enclose it in that while still outside. The next morning, after the telescope has warmed to room temperature again, open the case and caps for a short time to let any trapped moisture out.
The Moon and Planets
Tomorrow morning (Monday) before dawn, look for the old crescent moon sitting over the southeastern horizon, among the stars of Virgo (the Maiden). After about 6 am local time, the very bright planet Venus will pop above the horizon below the moon. You’ll be able to see Venus climb a bit higher as the sky lightens.
Because the moon is continuously circling Earth once every 27 days, its position in the sky jumps eastward from night to night — or morning to morning, in this case. On Tuesday morning, the even thinner moon will descend to sit nearly an outstretched fist’s diameter to the left of Venus. Venus will remain a fixture in the eastern pre-dawn sky for most of the winter.
We will temporarily lose sight of the moon while it passes its New Moon phase next to the sun on Wednesday morning. But the young, slender crescent will re-appear just above the western horizon for a few minutes after sunset on Wednesday evening.
On Thursday evening, the still-slim moon will set well after the sun, and gleam prettily in the western evening sky until about 6 pm local time. Sharp eyes might spot the second brightest planet, Jupiter, sitting only a couple of finger widths below the moon. Be quick, though — Jupiter will set at about 5:41 pm local time. On the same evening, Mercury will be 10° (a fist’s diameter) to the left of the moon and Jupiter. The two planets will stay put while the moon climbs higher from Friday onwards. In a telescope Mercury will show a half-illuminated disk, but distant Jupiter will show a full disk. (For eye safety, be sure to wait until the sun has vanished completely before using binoculars or a telescope on Jupiter and Mercury.) Mercury will reach its maximum angle from the sun on Tuesday, and then begin to swing sunward again.
On the coming weekend, the waxing moon will visit yellowish Saturn, which has been spending this year near the Teapot-shaped stars of Sagittarius (the Archer). The ringed planet will appear as a medium-bright, yellowish dot sitting relatively low in the southwestern sky after dusk. The moon will sit nearly a fist’s diameter to Saturn’s lower right on Saturday and just a few finger widths to Saturn’s upper left on Sunday. Whether it’s being “mooned” or not, Saturn will set before just 8 pm local time this week.
After the sky has darkened, even a small telescope should be able to show you some of Saturn’s larger moons, especially its largest satellite, Titan. Using a clock’s dial analogy, Titan will move counter-clockwise over the course of this week — starting from a position at 10 o’clock (to the upper left of Saturn) tonight, and ending up next Sunday at 4 o’clock (to the lower right of Saturn). (Remember that your telescope might flip and/or invert the view. Use the moon to find out how your telescope changes things and keep a note of it, since that will always be the case.)
Even though it is gradually dimming as Earth pulls farther away from it, reddish Mars will continue to dominate the southern evening sky this week. Mars will set in the west at about midnight local time.
Mars’ orbital motion has been carrying it eastward towards distant Neptune, which is less than two fist diameters to the left (east) of Mars now. The blue, ice giant planet is visible from dusk until just after 1:30 am local time. Using a decent quality telescope you can see the magnitude 7.8 planet sitting roughly midway between the modestly bright star Phi (φ) Aquarii and the brighter star Hydor (Lambda Aquarii). Neptune will highest in the sky (and best viewing conditions) at about 8 pm local time.
Blue-green Uranus is farther to the east than Neptune. It’s still close to its peak brightness (magnitude 5.7) and size for this year. You can see it without optical aid under very dark skies, but binoculars and telescopes will work better. By mid-evening, Uranus will be high enough in the eastern sky to see it clearly. Look for it about 2 finger widths to the left (east) of the modestly bright star Torcular (Omega Piscium). That star sits a generous palm’s width above the “V” where the two starry cords of Pisces (the Fishes) meet. The planet will be carried higher in the sky until 11 pm local time.
The Water Constellations — Capricornus the Sea-Goat
Evenings in late autumn feature a grouping of constellations over the southern horizon that share a common theme — the Sea. Collectively known as the water constellations, they aren’t very prominent, consisting mainly of modest and dim stars, but this week’s moonless sky will offer an opportunity to see them better. Over the two weeks, I’ll talk about each of the watery constellations.
First up, literally, is Capricornus (the Sea-Goat), the second dimmest constellation of the heavens. A zodiac constellation, it sits squarely on the ecliptic, and the sun passes through it from late January to mid-February every year. Its equatorial location also makes this constellation visible from everywhere on Earth.
As it happens, Mars will help you find Capricornus because the red planet is currently sitting near the easternmost of its major stars. The constellation spans an area about 3 outstretched fist diameters tall and 5 wide. This most westerly of the water constellations rises first and sets first, at about 10:45 pm local time this week. Mars is steadily sliding to the east, and will move next door into Aquarius (the Water-Bearer) by mid-month.
In Greek mythology, Capricornus represented the goat-like god Pan, who fled into the sea to escape a monster, whereby his legs were transformed into a fish tail. The ancient Sumerians, Babylonians, and the Romans all envisioned the same creature in these stars. The Tropic of Capricorn is the latitude where the Sun is directly overhead on the Winter Solstice. It is called that because many years ago, at the winter solstice, the Sun sat among those stars.
Visually, Capricornus consists of about nine modestly-bright stars arranged in a wedge or boat-shape, or perhaps a bikini bottom. Various star atlases and astronomy apps connect its stars differently. The brightest star, designated alpha, sits at the upper right (northwestern) corner of the constellation. It is also known as Giedi or Al Gedi, which roughly translates to “the billy goat”. This star is a nice wide double star easily discerned with unaided eyes, but the two stars are only a line-of-sight double. The nearer star is about 100 light-years away, while the farther one is almost 700 light-years away! Both stars are orange-yellow, about as hot as the Sun. The Chinese call this star 牛宿二 (Niú Sù Èr), the Second Star of the Ox.
About two finger widths below Giedi is another easy double star named Dabih “lucky star of the slaughterer”, that should readily split apart in binoculars. At the opposite hip of the bikini sits the brighter star Deneb Algedi “tail of the goat”. At the moment, that star is just below bright red Mars. The slightly dimmer star sitting less than two finger widths to the right of Mars and Deneb Algedi is called Nashira “bearer of good news”, and is located about 139 light-years away from our us.
If you scan the sky about a palm’s width below and a little to the west of Deneb Algedi, you should be able to spot a small fuzzy patch that is the globular star cluster Messier 30. This collection of 200,000 tightly packed stars orbits our galaxy’s centre and is located 26,000 light-years away from the sun.
Astronomy Skylights for the week of November 4th, 2018 by Chris Vaughan.
Keep looking up, and enjoy the sky when you do. I love questions and requests — so, send me some!