The July 2024 New Moon occurs today when the Earth reaches its farthest point from the Sun, known as aphelion.
According to the US Naval Observatory, the new moon will arrive on July 5 at 18:57 ET (2257 UTC), and two days later the young moon will make a close approach to Mercury in the evening sky.
Earth reached aphelion today, meaning ours was further from the Sun than at any other time in its annual orbit. The Earth’s orbit around the Sun is slightly elliptical, or oval, meaning that our distance from our star can vary by as much as 3% over the course of a year. This small deviation is not significant enough to be noticeable to most observers.
A new moon occurs when the moon is directly between the sun and the earth; in many lunar calendar systems they mark the beginning of a lunar month. Technically speaking, the Sun and Moon are in conjunction, on the same north-south line that passes through the celestial pole. The timing of the moon’s phases is measured by where the moon is relative to the Earth, so that a given phase occurs at the same time around the world. Any differences are only due to the time zone one is in – for example, in Melbourne, Australia, the new moon occurs at 8:57am on July 6th.
New moons are invisible unless there is an eclipse; an eclipse does not occur at every new moon because the orbits of the Moon and Earth are not perfectly aligned; they are inclined to each other by about 5 degrees. The moon’s shadow then “passes” the Earth most of the time. (The next solar eclipse will not be until October 2, 2024).
Close transit to Mercury
On the evening of July 7, the Moon will transit Mercury as it moves out of a new phase; thin crescent will be some 3 degrees north of Mercury at 2:33 PM ET, according to the skywatching website In-the-Sky.org. At sunset, when the Moon becomes visible, it will be about 16 degrees above the horizon; Mercury will be under the Moon. But the planet won’t really be visible until around 9:00 p.m. (sunset that day is at at about 8:29 p.m. in New York; times are similar in cities like Chicago or Sacramento) and by then it will only be 8 degrees, so from anywhere in the mid-northern latitudes the conjunction will be a challenge – one will need a flat, unobstructed, clear horizon.
Observing the conjunction is easier as one approaches the equator. From lower latitudes (either north or south), the ecliptic, or the plane of Earth’s orbit projected onto the sky, makes a steeper angle with the horizon. This means that planets that all move within a few degrees of the ecliptic tend to reach higher altitudes. (This is also why tropical sunsets seem so short, while sunsets at higher northern and southern latitudes seem to linger—in the tropics, the Sun approaches the horizon almost straight down, while in more northern or southern regions it approaches more gently ).
From Miami, the conjunction occurs at 2:33 PM local time, but both the Moon and Mercury will be higher in the sky; and The sun sets at 20:16 local time, and at that moment the Moon is 20 degrees high and Mercury 18 degrees above the western horizon. By 8:30 p.m., Mercury should be just visible and still about 12 degrees high, so with a clear, unobstructed horizon, one should be able to catch it.
From Bridgetown, Barbados (and similar latitudes), the moon will appear to the right of Mercury and at sunset, at 19:29 local timeThe Moon is a full 18 degrees west, still 14 degrees above the horizon at 7pm, as is Mercury, and both will be more visible than from the continental US
In the Western Hemisphere, the conjunction itself occurs in the afternoon, during daylight hours, but as one moves east, the moment of conjunction shifts to the evening. From Madrid, Spain, the viewing challenges are similar to New York (the two cities are at nearly the same latitude), but the conjunction occurs at 8:33 p.m. local time.
In the Southern Hemisphere, observing is a little easier – the days are shorter because of the Aussie winter. In Sao Paolo, the sun sets at 17:22 local time, and while the conjunction will occur at 15:33, still during the day, at sunset the Moon will be 18 degrees in the northwest and Mercury will appear above it. to the left of the moon. Mercury will not be visible until around 6pm and will still be about 12 and a half degrees. In Cape Town, where the conjunction occurs at 20:33 local time – Sunset is at 5:51 p.m and the Moon and Mercury set at 19:34; about half an hour after sunset the couple is about 13 degrees high in the northwest.
Visible planets
Venus will emerge in the evening sky, but will still be largely lost in the sunlight; though at sunset it appears a little higher as one approaches the equator, it is not more than five or six degrees higher, as the sky begins to darken.
Saturn is the first planet to rise, July 5 at 11:40 PM in New York. In the constellation of Aquarius, a fainter star group than many others, it will be quite distinct in its area of ​​the sky. When the sky begins to lighten from about 4:30 to 5:00 a.m. (the morning of July 6), it will be about 41 degrees above the south-southeast horizon.
Mars will be prominent in the early hours of the morning; as the year progresses, it rises later and the planet is eventually lost in the light of the sun’s dawn. On the night of the new moon (July 5-6) in mid-northern latitudes, the planet will rise at about 2 a.m. — it rises at 2:03 a.m. in New York, and the time will be similar in cities like Chicago. (1:56 a.m. CDT), Denver (2:10 a.m. MDT) and Sacramento (2:18 a.m. PDT). Mars will be in the constellation of Aires and will be easy to spot because Aires is made up of fainter stars.
Jupiter rises after Mars at 3:07 a.m. EDT in New York. Jupiter is in Taurus and is to the left above Aldebaran, the brightest star in this constellation. Aldebaran is noticeably more orange and flickers, making it easier to spot the planet, which is white-yellow and emits a constant light.
This means that at about 4:30 a.m. local time in mid-northern latitudes, the three planets that are further from the Sun than Earth to the naked eye will form a sort of line across the sky from the eastern horizon to the right, starting with Jupiter and ending with Saturn.
In the Southern Hemisphere, such as in Melbourne, Australia (where there is a new moon on July 6th), these three planets will also form a line, but this time up and to the left (as one to the north). Saturn will also be higher in the sky. In Melbourne (and other mid-southern latitudes) Saturn will rise at 10:22 PM AEST on July 6; when the planet transits (crosses the north-south line in the sky) at 4:43 a.m. on July 7, it will be a full 58 degrees above the northern horizon. Mars rises at 3:22am AEST and Jupiter at 4:47am Jupiter’s position in the sky relative to Aldebaran will be reversed; Jupiter will appear below Aldebaran rather than above (it will still appear to the left).
Summer stars
For Northern Hemisphere skywatchers, the summer triangle is high in the eastern sky around 10:00 p.m.; The “top” star is Vega, the brightest star in Lyra the Lyre, and is almost at the zenith (about 70 degrees above the horizon). The other two stars in the Summer Triangle are Deneb and Altair, both to the east (left) of Vega; from a dark sky location, the Milky Way can be seen inside the triangle. The three stars form a rough right triangle with Altair at the southern end.
When you turn left – towards the north you will see the Big Dipper on the left (west) and slightly below the Pole Star, the Polar Star. If you follow the “pointers” (the two stars at the front of the Dipper bowl, Dubhe and Merak) to Polaris and continue straight across, you’ll come across King Cepheus, and just below Cepheus is the “W” shape of Cassiopeia, which will be low in the northeast.
In the opposite direction, follow the handle of the great chariot and “arc to Arcturus”, the brightest star in Boötes, the Shepherd, and continue down to meet Spica, the brightest star in Virgo. If you turn south (left) you will see the bright red star Antares, the heart of Scorpio, and in the darker places in the sky looking up (north) from Scorpio you will see Ophiuchus the healer with Sagittarius and his “kettle” to the left. Scorpius.
In mid-southern latitudes one sees the stars of winter – darkness comes earlier. At 7 p.m., the sky is dark and the Southern Cross is high above the southern horizon, about 65 degrees. To the left of the Cross (east) is Alpha Centauri, also called Rigil Kentaurus, our nearest stellar neighbor. Further east and closer to the horizon is Scorpio, though upside down (from a Northern Hemisphere observer) and very high in the sky; Antares has an altitude of a full 47 degrees at 7 p.m
In the southwest, the ship’s keel, Puppis, sets in, and is marked by Canopus, about 20 degrees above the southwest horizon. Canopus is the second brightest star in the night sky after Sirius. In the same area of ​​the sky to the left (toward the south) are the Large Magellanic Clouds and the Small Magellanic Clouds, two satellite galaxies of the Milky Way.