FRIDAY, OCTOBER 9
■ Soon after dark, you'll find bright Arcturus low in the west-northwest at the same height as bright Capella low in the northeast. When this happens, turn to the south-southeast, and there will be Fomalhaut at about the same height — exactly so if you're at latitude 43° north (Boston, Buffalo, Milwaukee, Boise, Eugene). If you're south of that latitude, Fomalhaut will be higher than the other two. Seen from north of there it will be lower.
SATURDAY, OCTOBER 10
■ The Great Square of Pegasus still balances on its corner high in the east in early evening. Extending away from the Square's left corner is the main line of Andromeda, three 2nd-magnitude stars about as bright as those of the Square and spaced similarly far apart. (The three include the Square's corner itself.) This whole giant dipper-shaped pattern was named the Andromegasus Dipper by the late Sky & Telescope columnist George Lovi — joining the Big and Little Dippers, the Milk Dipper of Sagittarius (nowadays usually subsumed into the Teapot), and the tiny dipper pattern of the Pleiades.
Extend the Andromeda line farther left to Alpha Persei, and Andromegasus gains a longer handle to more resemble a giant Little Dipper.
■ Before dawn begins on Sunday morning the 11th, use binoculars or a telescope to catch Mars (high in the southeast over bright Jupiter) in the midst of the Beehive star cluster. Go out about two hours before sunrise. The Beehive is almost 1° wide, but Mars now shines very close to its brightest star, Epsilon Cancri, magnitude 6.3. Mars outshines it by more than 100 times.
■ New Moon (exact at 11:50 a.m. EDT).
SUNDAY, OCTOBER 11
■ As October proceeds, Deneb slowly replaces Vega as the zenith star of early evening (for skywatchers at mid-northern latitudes). Accordingly, dim Capricornus has replaced Sagittarius as the zodiacal constellation having its best display in the south.
MONDAY, OCTOBER 12
■ Vega is the brightest star very high in the west these evenings, still almost overhead at nightfall. Less high toward the southwest is Altair, not quite as bright. Just upper right of Altair, by a finger-width at arm's length, is little orange Tarazed. Down from Tarazed runs the dimmer stick-figure backbone of the constellation Aquila, the Eagle, alongside the spine of the Milky Way.
TUESDAY, OCTOBER 13
■ The Great Square of Pegasus is high in the east-southeast after dark — still, for now, almost balanced on one corner (for the world's mid-northern latitudes). But the Square moves higher to the south and turns level like a box by 10 or 11 p.m. now.
WEDNESDAY, OCTOBER 14
■ As twilight fades down, catch the crescent Moon low in the southwest. Can you make out twinkly Antares very close to its right? They'll be about 1° or 2° apart depending on your location (in North America). See below.
And now the crescent Moon begins returning to the evening sky, passing bleary-eyed, out-of-season Antares. Which is on its final way down for the year. Bring binoculars.
THURSDAY, OCTOBER 15
■ Cassiopeia lies astride the winter Milky Way. It thus offers lots of open star clusters for telescopes, including some within range of binoculars depending on the quality of your sky. Three of my favorite Cas clusters to try for are NGC 457 (the Owl or ET cluster, which includes 5th-magnitude Phi Cassiopeiae); M103, dominated by a tiny line of three stars magnitudes 7.2, 8.2, and 7.5, 0.1° long; and fluffier NGC 663.
In 7 x 50 binoculars NGC 457 looks to me like a subtle little windblown candleflame, being blown northwestward from its base of Phi Cas and Phi's 7th-mag binocular companion.
The visibility of these subtle little cluster-glows will depend, of course, on your light pollution and your instrument. I have no trouble with them using 10x50 binocs under a moderately light-polluted suburban sky.
Cassiopeia is shown here with north toward the left, oriented like the naked-eye and binocular view of it when it's getting high in the northeast on October evenings. If the three open clusters here are too faint for your conditions, just drop down by twice the length of the near-vertical segment here, and pow, there's the Double Cluster in Perseus, much closer and brighter and a fine consolation prize.
It's always a big help to brace your binoculars against something as still as you can. When looking high up, try lying on the ground with something next to your head to brace them against.
And you need to know exactly where to look. The view of Cassiopeia here shows the clusters' precise locations amid the Cassiopeia W and its star fields.
FRIDAY, OCTOBER 16
■ As soon as the sky is fully dark, spot the thick crescent Moon low in the southwest. Tonight it's in the Sagittarius Teapot, which is made of 2nd- and 3rd-magnitude stars. The Teapot is now steeply tilted to pour. Its triangular spout is below the Moon, and its four-star handle is to the Moon's upper left (at the times of nightfall in North America).
■ Mars, Jupiter, and Regulus continue to draw together high in the southeast before and during early dawn. If you get up early, keep an eye on them. Mars and Jupiter will pass each other by 1.2° exactly a month from now, and the three will bunch up most closely around November 25th.
Mars, Jupiter, and Regulus are lined up before and during early dawn this month. A better, darker view will be had 1½ hours or more before sunrise.
SATURDAY, OCTOBER 17
■ The Moon now shines a little upper right of the Teapot's handle right after dark (for North America).
■ Algol, the prototype eclipsing binary star, should be its minimum brightness, magnitude 3.4 instead of its usual 2.1, for a couple hours centered on 9:52 p.m. EDT.
SUNDAY, OCTOBER 18
■ First-quarter Moon (exact at 12:13 p.m. EDT). The Moon shines in the south-southwest this evening. Spot Altair about three fists at arm's length to the Moon's upper right, and Fomalhaut roughly the same distance to the Moon's left. Both are 1st-magnitude white stars quite nearby as stars go: 17 and 25 light-years away, respectively.
This Week's Planet Roundup
Mercury (magnitude 0.0) is hidden way down deep in the bright sunset.
Venus is plain out of sight in conjunction with the Sun.
Mars (magnitude +1.0, in Cancer) rises in the east-northeast around 1 a.m. daylight-saving time, below Castor and Pollux. By the beginning of dawn you'll find Mars glowing high in the east with Castor and Pollux still above it, Procyon to its right, and brilliant Jupiter below it. Below Jupiter will be Regulus, the brightest star of "springtime" Leo.
Mars is currently the near-twin of Pollux for both brightness and color. Castor is white and somewhat fainter at magnitude +1.6 (that's the combined brightness of its two telescopic components, which are currently 5.8 arcseconds apart).
In a telescope Mars is still just a tiny, fuzzy blob 6 arcseconds wide.
Jupiter (magnitude –1.9, in Leo) rises in the east-northeast around 2 a.m. roughly a fist below Mars. Once it's well up it shines steadily in the east as the brightest point in the sky, until becoming lost in the growing dawn. In a telescope it's only 34 arcseconds wide.
Mars is slowly closing in on Jupiter from above. They'll pass each other at conjunction, 1.2° apart, on the morning of November 16th.
Jupiter at 21:10 UT September 26th, imaged by Christopher Go. North is up. Io is on the central meridian, casting its black shadow to the west. Notice that Jupiter's eastern side is the brightest. That's the side currently pointed more toward the Sun, because Jupiter is pre-opposition.
Saturn (magnitude +0.4, at the Pisces-Cetus border) was at opposition last week. As twilight fades, it'll be the first point of light that comes into view low in the east. Don't confuse it with twinklier Fomalhaut, magnitude 1.2, low in the southeast.
Saturn climbs higher through the evening. It's best placed for steady telescopic views high toward the south from late evening through early morning. It transits around midnight or 1 a.m. daylight saving time.
Uranus (magnitude 5.6, in Taurus) is midway between the Pleiades and Aldebaran, which are well up in the east by mid- to late evening.
Neptune (magnitude 7.8, in Pisces) hides 8° west of Saturn. You'll need detailed finder charts to tell Uranus and Neptune from stars of similar brightnesses in their area.
"Facts are stubborn things; and whatever may be our wishes, our inclinations, or the dictates of our passion, they cannot alter the state of facts and evidence."
— John Adams, 1770