This week’s sky peek, October 1-9 – Sky & Telescope
New Cassiopeia 2021 had returned to magnitude 7.8 by September 28, and he might blush again. Charts and comparison stars.
FRIDAY OCTOBER 1
■ Vega is the brightest star just west of the zenith after dark this week. Face west, lift your head and look to Vega’s right at 14 ° (nearly a fist and a half at arm’s length) for 2nd magnitude Eltanin, the nose of Draco the dragon. The rest of Draco’s paler, diamond-shaped head is a little further behind. Draco is still watching Vega as they circle in the sky.
The main stars of Vega’s own constellation, Lyra – faint in comparison – extend to the left of Vega by half as far as Vega’s distance from Eltanin.
■ Bright Jupiter and weaker Saturn continue to dominate southeast to south these evenings, 16 ° apart.
Look at the top right of Saturn, by 6 ° or 8 °, for the 3rd magnitude Alpha and Beta Capricorni. Both are binocular double stars. Alpha, the top one, is a large pair of yellow-orange giants that smaller binoculars easily resolve. The components of Beta are rather harder; they are half the distance from each other and much more unequal. They are oriented in much the same way as the Alpha pair. (To learn more about these stars and their surroundings, see “Capricious Capricornus” in the Sky and Telescope, page 45.)
■ This evening, the great red spot of Jupiter is expected to cross Jupiter’s central meridian around 9:54 pm EDT. The red spot remains closer to the central meridian than to the planet’s limb for 50 minutes before and after its transit.
■ Before and during dawn on Saturday morning October 2, look under the crescent moon about a fist at arm’s length for Regulus. This is Leo’s forefoot, which is already on the cusp of his early onset, as shown below.
SATURDAY, 2 OCTOBER
■ During the evening, look just above the northeast horizon – well below High Cassiopeia – to see Capella shining upward. How quickly Capella gets up and how high you find her depends on your latitude. The further north you are, the earlier and higher.
■ Vega is the brightest star very high in the west, while Arcturus lowers in the west-northwest. The brightest star in the vast expanse between them, about a third of the way from Arcturus to Vega, is Alphecca, magnitude 2.2 – the crown jewel of the Sun Corona Borealis. Alphecca is a 17-day eclipse binary, but (like most variable stars!) Its brightness drops are too small for the eye to see reliably.
■ Before and during dawn on Sunday morning October 3, the waning crescent moon forms a flat, almost isosceles triangle with Regulus and Algieba (Gamma Leonis) to the left or top left of Regulus, as shown above (for l ‘North America).
SUNDAY, OCTOBER 3
■ Red globular clusters are most abundant on summer evenings. On that first week of October, with the moonlight fading from the evening sky, set up your telescope to observe four that Josh Urban calls The Last Wildflowers: Globular Clusters Greet Autumn. There is “Sagittifolia”, the Arrowhead Flower M71 in Sagitta; “Queen Anne’s lace,” M15 sneezed from Pegasus’ nose; “Watercress at the edge of the brook”, M2 in Aquarius a little further south; and “Seaflower of the Deep”, M30 in Capricorn below Jupiter.
MONDAY, OCTOBER 4
■ Jupiter’s moon Io enters the face of the planet at 9:19 p.m. EDT, followed by its tiny black shadow an hour later. Io left the west side of Jupiter at 11:36 p.m. EDT, again followed by his shadow an hour later. See the “Action in Jupiter” schedules for the whole month, valid worldwide, in October Sky and Telescope, pages 50-51.
TUESDAY, OCTOBER 5
■ Arcturus shines in the west at nightfall on these evenings. Capella, just as bright, rises in the northeast (depending on your latitude, the further north you are, the higher it will be). They are both of magnitude 0.
Later that evening, Arcturus and Capella glow at equal heights in their respective compass directions. When will this happen? It depends on both your latitude and longitude.
When it does, turn around and look low to the southeast. There will also be 1st magnitude Fomalhaut at roughly the same height – exactly so if you are at latitude 43 ° north (approximately the latitude of Boston, Buffalo, Milwaukee, Boise, Eugene). Seen from the south of this latitude, Fomalhaut will appear higher than Capella and Arcturus. Seen from the north from there, it will be lower.
WEDNESDAY, 6 OCTOBER
■ Now that it is October, Deneb has replaced Vega as the zenith star of the dark early evening (for sky watchers in northern mid-latitudes). As a result, Capricorn replaced Sagittarius as the lower zodiacal constellation in the south. This year, of course, Capricorn is overwhelmed by its two brilliant temporary residents: Jupiter and Saturn.
■ New Moon (exactly 7:05 a.m. EDT).
THURSDAY, OCTOBER 7
■ The Grand Carré de Pégase balances at its high east corner for much of the evening. Far from the left corner of the Grand Place stretches the main line of Andromeda, three stars of magnitude 2 about as bright as those in the Square and spaced the same way. (All three include the corner of the square.) This whole ladle-shaped pattern was named the Andromegasus Dipper by the end Sky and Telescope columnist George Lovi – joining the Big and the Little Dipper, the Sagittarius Milk Ladle (nowadays generally included in the Teapot) and the small Pleiades ladle motif.
FRIDAY 8 OCTOBER
■ Spot Venus low in the southwest as early as possible at dusk. Then look down right about 12 ° (about a fist at arm’s length) for the thin crescent moon. The binoculars help.
If you find the perfect time to compromise between the sky still too bright and the Moon falling too low, you should have a good view of the dimly lit Earth on nights of the Moon inside the crescent. And the Moon is at perigee today, so a larger-than-average trace will appear: a supercrescent moon.
SATURDAY, OCTOBER 9
■ Now the Moon shines only about 3 ° above Venus at dusk (for North America), while Venus passes ¾ ° to the lower left of the magnitude 2 Delta Scorpii, as shown below. below. Bring binoculars.
This week’s tour of the planets
Mstable and March are out of sight in conjunction with the Sun.
Venus, glowing at a magnitude of –4.3, shines faintly in the southwest at dusk, in Libra. It sets a little after dusk has ended.
Look to the left of Venus as dusk thickens for the orange Antares in Scorpius. Between them for most of the week is Delta Scorpii, not too weak as Antares. Binoculars will help you spot the two stars in the intensifying blue.
Watch Venus come closer to Delta Sco day in and day out. They pass just ¾ ° apart on October 9, with the thin crescent Moon right next to it, as shown above. A week later, on the 16th, Venus will pass at 1½ ° above Antares.
Jupiter and Saturn continue to shine from southeast to south during the evening, 16 ° apart on opposite sides of weak Capricorn. Jupiter is the focal point at magnitude -2.7. Saturn, to its right, is a twentieth as bright at mag +0.5.
At the end of dusk, they also sit high in the south-southeast. As the evening wears on, watch them tilt to the right, with Saturn at the bottom. Saturn sets around 1 or 2 a.m. DST, followed by Jupiter about an hour later.
After dark, look at 23 ° (two fists at arm’s length) at the bottom left of Jupiter for Fomalhaut of 1st magnitude. About 2 ° lower left of Jupiter, 3rd magnitude Delta Capricorn spot.
Here is a telescopic beginner’s guide to Jupiter.
Uranus (magnitude 5.7, in southern Aries) rises high in the east around 11 or midnight.
Neptune (magnitude 7.8, on the Aquarius-Pisces border) is already well elevated in the southeast by the time the darkness is complete.
All descriptions that relate to your horizon, including the words up, down, right, and left, are written for the northern mid-latitudes of the world. The descriptions which also depend on longitude (mainly the positions of the Moon) relate to North America.
Eastern Daylight Time, EDT, is Universal Time less 4 hours. Universal Time is also known as UT, UTC, GMT, or Z. To become more expert in time systems than 99% of the people you will meet, check out our compact article Time and the Amateur Astronomer.
Want to become a better astronomer? Learn your way around the constellations. They are the key to locating anything lower and deeper to hunt with binoculars or a telescope.
It is an outdoor nature pastime. For an easy-to-use constellation guide covering the entire evening sky, use the large monthly card in the center of each issue of Sky and Telescope, the essential magazine of astronomy.
Once you get a telescope, to put it to good use, you will need a detailed and large scale sky atlas (set of maps). The basic standard is Pocket Sky Atlas (in the original or Jumbo edition), which shows stars of magnitude 7.6.
Then comes the biggest and the deepest Sky Atlas 2000.0, tracing the stars up to magnitude 8.5; almost three times more. The next one, once you know your way, are even bigger Interstellar atlas (stars of magnitude 9.5) or Uranometry 2000.0 (stars of magnitude 9.75). And be sure to read How to use a star map with a telescope.
You will also need a good deep sky guide, like the great Night sky watcher’s guide by Kepple and Sanner.
Can a computerized telescope replace maps? Not for beginners, I don’t think so, and not on mounts and tripods which are mechanically inferior, i.e. heavy and expensive. And as Terence Dickinson and Alan Dyer say in their Backyard Astronomer’s Guide, “A full appreciation of the universe cannot come without developing the skills to find things in the sky and understand how the sky works. This knowledge only comes from spending time under the stars with star maps. in hand.”
Audio Sky Tower. Out under the evening sky with your
headphones in place, listen to Kelly Beatty’s monthly
Tower of Heaven podcast above. It’s free.
“The dangers of not thinking clearly are much greater than ever. It’s not that there is something new about the way we think, it’s that gullible and confused thinking can be much deadlier than it is. ‘she has never been before. “
– Carl Sagan, 1996
“Facts are stubborn things.”
– John Adams, 1770