The July 2024 new moon occurs today when Earth reaches its farthest point from the sun, known as aphelion.
The new moon arrives on July 5 at 6:57 p.m. Eastern Time (2257 UTC), according to the US Naval Observatory, and two days later the young moon will pass close to Mercury in the evening sky.
Today, the Earth reached aphelion, meaning that we have been further from the sun than at any other time in its annual orbit. Earth’s orbit around the sun is slightly elliptical, or oval in shape, meaning our distance from our star can vary by up to 3% over the course of a year. This small variation 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 the lunar month. Technically, the sun and moon are in conjunction, on the same north-south line that passes through the celestial pole. The timing of the moon phases is measured by where the moon is relative to the Earth, so a given phase occurs at the same time around the world. Any differences are due only to the time zone one is in – in Melbourne, Australia, for example, the new moon occurs at 8:57am on July 6th.
New moons are invisible unless there is an eclipse; eclipses do 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 “misses” Earth most of the time. (The next solar eclipse isn’t until October 2, 2024).
Close transit to Mercury
In the evening hours of July 7, the moon will pass by Mercury as it exits the new phase; the thin crescent will be some 3 degrees north of Mercury at 2:33 PM ET, according to the sky-watching site In-the-Sky.org. At sunset, when the moon becomes visible, it will be about 16 degrees above the horizon; Mercury will be below the moon. But the planet won’t be visible at all until about 9 p.m. (sunset that day is at around 8:29 p.m. in New York; times are similar in cities like Chicago or Sacramento) and it will only be 8 degrees high at that time, so from anywhere in the mid-northern latitudes the conjunction will be a challenge to see—you’ll need a flat, unobstructed, clear horizon.
Observing the connection becomes easier as one approaches the equator. From lower latitudes (north or south) the ecliptic, or the plane of the earth’s orbit, projected onto the sky, makes a steeper angle with the horizon. This means that planets that move within a few degrees of the ecliptic tend to reach higher altitudes. (This is also why tropical sunsets seem so short, while sunsets in 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 below slight slope).
From Miami, the conjunction takes place at 2:33 p.m. local time, but both the moon and Mercury will be higher in the sky; on the sun sets at 8:16 p.m local time and at this time the moon is 20 degrees high and Mercury is 18 degrees above the western horizon. Around 20:30 Mercury should become visible and will still be about 12 degrees, 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, at 7pm it is still 14 degrees above the horizon, as is Mercury, both of which will be more visible than from the continental US
In the Western Hemisphere, the conjunction itself occurs in the afternoon, in daylight, but as you move east, the moment of conjunction moves to the evening. From Madrid, Spain, the viewing challenges are similar to those in 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 as it is the austral winter. In Sao Paulo, the sun sets at 5:22 PM local time and while the conjunction occurs at 3:33 PM, still during the day, at sunset the moon will be 18 degrees northwest and Mercury will appear above and to the left from the moon. The mercury won’t become visible until around 6pm and it will still be around 12.5 degrees. In Cape Town, where the merger takes place at 20:33 local time – sunset is at 5:51 p.m and the moon and Mercury set at 7:34 p.m.; about half an hour after sunset, the pair is about 13 degrees high in the northwest.
Visible planets
Venus will appear in the evening sky, but will still be largely lost in the sun’s glare; although it appears a little higher in the sky at sunset as one approaches the equator, it is no more than five or six degrees when the sky begins to darken.
Saturn is the first planet to rise at 11:40 PM on July 5 in New York. In the constellation Aquarius, which is a fainter star group than many others, it will be quite distinct in its region of the sky. When the sky begins to lighten around 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 wee hours of the morning; as the year progresses, it rises later and the planet will eventually be lost in the light of the sun. On the night of the new moon (July 5-6) in the mid-northern latitudes, the planet will rise around 2 a.m. — it rises at 2:03 a.m. in New York, with similar times 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 Ayres and will be easily visible as Ayres consists 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 of and above Aldebaran, the brightest star in this constellation. Aldebaran is noticeably more orange and shimmers, making it easier to recognize the planet, which is white-yellow and emits a constant light.
This means that around 4:30 a.m. local time in the mid-northern latitudes, the three naked-eye planets farther from the sun than Earth will make 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, for example in Melbourne, Australia (where the new moon is on July 6th) the three planets will also form a line, but this time up and to the left (since one faces north). Saturn will also be higher in the sky. In Melbourne (and other mid-southern latitudes) Saturn will rise at 10:22pm EST 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 3:22 a.m. AEST and Jupiter at 4:47 a.m. 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 be to the left).
Summer stars
For Northern Hemisphere sky watchers, around 10:00 PM the summer triangle is high in the eastern sky; the “top” star is Vega, the brightest star in Lyra Lyra, 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 place with a dark sky, the Milky Way can be seen inside the triangle. The three stars form a rough right triangle with Altair at the southern end.
Turning left – north you will see the Big Dipper to the left (west) and just below the North Star, the Pole Star. Following the “pointers” (the two stars at the front of Copha’s bowl, Dubhe and Merak) to Polaris and continuing straight through meets Cepheus, the king, and just below Cepheus is the “W” shape of Cassiopeia, which will be low in the northeast.
In the other direction follow the handle of the great bear and “arc to Arcturus” the brightest star in Volovar the shepherd, and continuing down you strike Spica, the brightest star in Virgo. Turning to the south (left), one sees the bright red star Antares, the heart of Scorpio, and in places with darker skies, looking up (north) from Scorpio, one sees Ophiuchus the healer, with Sagittarius and its “teapot” shape left of Scorpius.
In the mid-southern latitudes, the stars of winter are visible – darkness comes earlier. By 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 (to the east) is Alpha Centauri, also called Rigil Centauri, our nearest stellar neighbor. Further east and closer to the horizon is Scorpius, though upside down (from the perspective of a northern hemisphere observer) and very high in the sky; Antares is a full 47 degrees above sea level by 7 p.m
To the southwest the ship’s keel, Puppis, sets 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 region of the sky to the left (south) are the Large Magellanic Cloud and the Small Magellanic Cloud, two satellite galaxies of the Milky Way.
