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Sky and telescope jupiter moons1/1/2024 On Friday morning the 23rd, Regulus will be left of the Moon - forming a smaller, flatter isosceles triangle with those two stars. The Moon forms the tip of a nearly isosceles triangle with Regulus and yellow-orange Gamma Leonis. ■ In early dawn tomorrow the 22nd, the waning crescent Moon hangs above Regulus in the east as shown below. Because a line from Mizar through Alcor always points to Vega. Can you see its tiny close companion Alcor? Since this is the time of year when Vega is crossing the zenith in early evening, it's also when Alcor stands straight over Mizar. Examine Mizar, the middle star of its bent handle. ■ Spot the Big Dipper scooping low in the northwest. Its companion, magnitude 6.3, is 41 arcseconds away. In a telescope Delta Cep is also a lovely double star. Use the chart for this trio in Matt Wedel's Binocular Highlight column with the September center chart. Those two comparisons nearly frame Delta's brightness range. Make a point of looking up from time to time and comparing Delta with nearby Epsilon and Zeta Cephei, mags 4.2 and 3.3 respectively. It's home to the prototype Cepheid variable star, Delta Cephei.ĭelta Cep remains naked-eye throughout its cycle it pulses from magnitude 4.4 to 3.5 and back every 5 days 9 hours. ■ House-shaped Cepheus, in the edge of the Milky Way, is high in the northeast these evenings, as shown on the center star chart of the September Sky & Telescope. The Milky Way extends straight up from the southwest horizon between Sagittarius and the tail of Scorpius, passes overhead, and runs straight down to the northeast through Cassiopeia and Perseus. ■ This is the time of year when the rich Cygnus Milky Way crosses the zenith in the hour after nightfall is complete (for skywatchers at mid-northern latitudes). Seen from north of there, it will be lower. Seen from south of that latitude, Fomalhaut will appear higher than Capella and Arcturus are. There will be 1st-magnitude Fomalhaut at about the same height too - exactly so if you're at latitude 43° north (Boston, Buffalo, Milwaukee, Boise, Eugene). When it happens, turn and look low in the south-southeast. Again, the time of this will depend on your latitude and longitude. Later in the evening, it's the turn of Arcturus and Capella to shine at the same height. When that happens, barely rising in the north-northeast is Capella (depending on your latitude the farther north you are the higher Capella will be.) How well can you time their exact balance? About a half hour after nightfall is complete, brighter Jupiter shines at the same height in the east. ■ Arcturus shines in the west these evenings after twilight fades out. They're to its upper right and right, respectively, as shown above. Once the Moon is well up, you can see that it makes a nearly equilateral triangle, 7° on a side, with the two horn-tip stars of Taurus: Beta and Zeta Tauri. The Moon rises around 11 or midnight in the northeast, two fists lower right of Capella. Use the finder chart in the August Sky & Telescope, page 49. Using a telescope or large binoculars, find them both in late evening using the article and charts in the September Sky & Telescope, page 49.Īnd some 20° west-southwest of Juno, brighter 4 Vesta shines on at about magnitude 6.4. Equally bright (or faint) this week is the asteroid 3 Juno about 10° to Neptune's west. ("Midnight" here refers to the evening date.) The later in the wee hours of the morning you look, the higher and telescopically sharper both will be. Mars now adds to the telescopic attraction. When the Moon is waning, the direction of sunlight gives its craters and mountains a different look than how most of us are used to seeing them - in the more convenient evening hours, when the Moon is waxing. That's a good two or three finger-widths at arm's length, but this is still the closest pairing of the Moon and a bright planet visible this month from North America. The Moon is about 4° or 5° from Mars as seen from the longitudes of the Americas. The Moon is less than a day from being last quarter. ■ The late-rising Moon shines in line with Mars and Aldebaran to its right, as shown below.
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