The moon is officially new at 1:55 p.m. on July 28 for observers in the Eastern Daylight Time zone. A new moon occurs when the moon is directly between the sun and Earth. Technically, the sun and moon are in conjunction, on the same north-south line that passes through the celestial pole, near the star Polaris. (The term conjunction is also applied to other celestial bodies, such as planets).
Lunar phases’ timing depends on where the moon is relative to the Earth, so they occur at the same time all over the world. Any differences are only because of the time zone you are in — in Melbourne, Australia, for example, the new moon occurs at 3:55 a.m. on July 29.
New moons are not visible unless there is an eclipse; eclipses don’t happen every new moon because the orbit of the moon is tilted by about 5 degrees relative to the plane of the Earth’s orbit, and the node — the point where the orbits intersect — moves relative to the Earth’s surface. So the moon’s shadow “misses” the Earth most of the time. (The next solar eclipse isn’t until October 25, 2022).
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In the predawn hours of July 26, the moon will pass by Venus as it moves into the new phase; the thin crescent will be some 4 degrees to the north of Venus. The moon and Venus will be in conjunction at 10:12 a.m. Eastern Time (1412 GMT), according to skywatching site In-the-Sky.org. Though the moment when the two share the same right ascension (celestial longitude) will be during the day, from New York City the two will both be above the horizon at about 3:54 a.m., well before sunrise, which is at 5:47 a.m. By about 5:30 a.m. they will be at an altitude of 14 degrees, high enough to see paired in the sky. The moon will appear to be above and to the left of Venus; it rises at 3:26 a.m. followed by Venus at 3:57 a.m.
After the new moon, on July 29 at 5:14 p.m. ET (2114 GMT), the moon will pass Mercury, though from mid-northern latitudes the one-day-old moon and planet pair won’t be easily visible — the sun sets in New York City at 8:14 p.m. and Mercury will only be about 7 degrees above the western horizon. By the time the sky starts to get dark (about 30 minutes after sunset) the planet will only be about 2 degrees high.
Observers closer to the equator will have a better chance of catching the two. As one moves to lower latitudes (either from the north or south pole) the ecliptic — the plane of the Earth’s orbit projected on the sky — makes a steeper angle with the horizon. That means planets, which all move within a few degrees of the ecliptic, tend to reach higher altitudes. From Port of Spain, Trinidad and Tobago, for example, the conjunction occurs on July 29 at 5:08 p.m. local time. Sunset is at 6:30 p.m local time, and at that point, Mercury is about 12 degrees high in the west. As the sky gets darker it will still be just high enough to see, along with the moon, but you need a nearly flat western horizon with no obstructions. The moon will be to the right of Mercury, though it will be a challenge to see also as the crescent will be very thin.
For the mid-northern latitudes, Mars will rise after midnight on July 29 — it clears the horizon at 12:31 a.m. in New York, and times are similar for cities such as Boston, Chicago, Seattle and San Francisco. In the constellation Aires, the Red Planet will stand out as it is as bright or brighter than most of the stars in that constellation. By about 3 a.m. local time one will be able to see Mars about 28 degrees high in the east.
Jupiter, meanwhile, rises before Mars does, at about 10:51 p.m. on July 29. Jupiter will be in the constellation Cetus and is so bright that it is, like Mars, immediately noticeable even from brightly lit city locations.
Saturn rises earliest in the evening, at 9:01 p.m. in New York City. The planet is in Capricornus and like Mars and Jupiter is in a relatively faint group of stars, making it easier to find. If one faces south at about 3 a.m. local time one will see Saturn, Jupiter and Mars forming a rough line across the sky from west to east.
Constellations: Northern Hemisphere
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For Northern Hemisphere sky watchers July is the time for summer constellations. By 10 p.m. local time the Summer Triangle is high in the eastern sky; the “top” star is Vega, the brightest star in Lyra the Lyre, and it is almost at the zenith (about 79 degrees above the horizon). The other two stars in the Summer triangle are of Deneb and Altair, both of which are east (to the left) of Vega, The three make a rough right triangle with Altair at the southern end. Vega makes an appearance in the film Contact, as the home of the aliens who send a message to Earth.
Looking north (again at about 10 p.m. local time from mid-northern latitudes) one will see the Big Dipper to the left (west) and below Polaris, the pole star. Following the “pointers” (the two stars in the front of the bowl of the Dipper, Dubhe and Merak) to Polaris and continuing straight across you encounter Cepheus, the king, and just below Cepheus is the “W” shape of Cassiopeia.
In the other direction, follow the handle of the big dipper and “arc to Arcturus” the brightest star in Bootes, the herdsman, and continuing downward you hit Spica, the brightest star in Virgo. Turning south, one sees the bright red star Antares, the heart of Scorpius, and in darker sky locations looking up (north) from Scorpio one sees Ophiuchus the healer, with Sagittarius and its “teapot” shape to the left of Scorpius.
Constellations: Southern Hemisphere
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In the mid-southern latitudes, the sun sets earlier (it being austral winter) and by 7 p.m. the sky is dark and the Southern Cross is high in the south. To the left of the Cross (east) is Alpha Centauri, our nearest stellar neighbor, and east of that is Scorpio, though upside-down (from the point of view of a northern hemisphere observer) and very high in the sky; Antares is a full 70 degrees in altitude by 7 p.m.
In the southwest, the ship’s keel, Puppis, is setting and marked by Canopus, the second-brightest star in the night sky after Sirius. In the same region of sky are the Large Magellanic Cloud and Small Magellanic Clouds, two satellite galaxies of the Milky Way.
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