Skylights: July 2022

Earth is at aphelion on the 4th, At a distance of 1.521 million kilometers (1.0117 AU), nearly 5 million kilometers farther from the Sun than in January. That difference is about 13 times the average distance to the Moon, or over 4 times the distance to the Webb Telescope.

The Sun crosses from Gemini into Cancer on the 20th, and is just 1° south of the Beehive Cluster, M44, on the 30th.

The waxing crescent Moon is less than 5° from the Beehive cluster, M44, in Cancer on the 2nd. Although low on the horizon and in deep twilight, this should make a nice pair in binoculars. On the 2nd, the Moon fills in a cap in Leo’s Sickle asterism to form a complete hexagon.

First quarter Moon is on the 6th, in Virgo, with Spica shining a few degrees to its left. The Moon appears just to the east of the star on the 7th. Early in the evening of the 9th, the Moon is less than 2° NNE of Antares in Scorpius.

July’s Full Buck Moon occurs on the night of the 13th. It is the lowest full Moon of the year, culminating at just 20°24’ over the southern horizon at 12:16am on the 14th. Note its position within the handle of the Teapot asterism of Sagittarius.

The waxing gibbous Moon passes by Saturn on the 15th-16th, and just 3° southeast of Jupiter on the 19th.

The Moon reaches last quarter on the 20th, with an occultation of Mu Piscium occurring just after midnight. The star will disappear behind the Moon’s illuminated limb at 12:45am, and reappear from the darkened limb at 1:43am.

On the 21st, the waning crescent is 3.3° west-southwest of Mars, and on the 23rd it joins the Pleiades and Hyades clusters in Taurus. On the 26th, the 27-day-old crescent appears just above Venus in the predawn sky.

The planet parade that has marched through the morning sky since the beginning of the year is finally extending its way into the evening sky, as Saturn and Jupiter are now above the horizon before midnight in July. 

Saturn, which rises at 11pm in early July and 9pm at the end of the month, is moving westward through eastern Capricornus. Its 0.5 magnitude pale yellow glow makes a neat little triangle with Deneb Algedi (Delta Capricorni) and Nashira (Gamma Capricorni), which changes perceptibly on a nightly basis..

Appearing between Saturn and Jupiter in our sky are three solar system objects that are seldom observed, but fairly easy to find using optical aid, and well worth your time to explore.

First is the brightest asteroid in the night sky, 4 Vesta. The 550km wide asteroid brightens to 6th magnitude in July as its distance from Earth closes to within 1.3 AU by the end of the month. It can be easily seen with binoculars moving through Aquarius, about 15° north of Fomalhaut.

Just a bit farther out is another of the first asteroids to be discovered, 3 Juno. Juno ranges from 2.0 to 1.6 AU, and brightens from magnitude 9.5 to 8.8. You’ll need large binoculars or a small telescope to find Juno, which can be found by drawing a line through the western edge of the Great Square of Pegasus, and continuing south about the same distance, to the vicinity of 3.7 magnitude Gamma Piscium.

And finally, the eighth planet Neptune shines as a tiny pale blue 7.7 magnitude point in southwestern Pisces. It can be found by drawing a line south through the easternmost pair of stars in the Circlet asterism, or, it can be found just a little over ¼ of the way along a line connecting Jupiter and Saturn.

The king of the planets, Jupiter, rises at 12:30am at the beginning of the month, and two hours earlier at the end of the month. 

Venus begins July in Taurus, located just a few degrees north of Aldebaran and extending the northern leg of the “V” asterism of the Hyades cluster. It continues moving eastward and passes within 1/2° north of the Crab Nebula (M1) supernova remnant on the 13th.

Venus then  passes through Orion from July 16tth-18th, and over the next two mornings is within 1.5° of the open star cluster M35 in Gemini. The 27-day-old waning crescent Moon appears nearby on the 26th.

Mercury rises 45 minutes before the Sun in early July, but rises later each day as it moves closer to superior conjunction on the 16th. It will become visible in the evening sky again at the end of the month, with the 1-day-old crescent Moon appearing 2.5° north of it on the 29th.

Pluto comes to opposition on July 20th, when it will be 33.550 AU from Earth, and shines at a pale 14.3 magnitude. To observe it visually, you’ll want to use a 12-inch or larger telescope, and wait for the Moon to be out of the sky. After having spent the last 14 years in Sagittarius, this will be the last full year that Pluto will reside fully within the constellation, as it crosses into Capricornus in March 2023.

If you’re a deep sky hunter, Pluto will be easy to locate, as it lies within 2° west-southwest of the globular cluster M75. There are many digital star atlases that can be used to give accurate positions for Pluto on a specific date, such as SkySafari. 

If you don’t have access to a large telescope, but have a camera and tracking mount, and a small telescope or telephoto lens, you will most likely be able to capture an image of Pluto. The best way to accomplish this is to image the same area of sky on successive nights, or a few nights apart, then “blink” the images to find the object that moved. Having M75 nearby will aid in framing, as well as give a point of interest to this year’s Pluto images.

In early July, the last stars of the Winter Hexagon, Pollux and Castor, drop out of  our evening sky, and the prominent spring constellation Leo can be seen descending into the west at the end of twilight. To the south, Antares, in Scorpius, is transiting the meridian, and high in the northwest, the Big Dipper has assumed its familiar summer position, with the pointer stars nearly due west of Polaris.

The core of the Milky Way lies due south during late evening this month, and the Summer Triangle is high overhead, making this the best time to observe the celestial wonders within this region of sky.

Comet C/2017 K2 PanSTARRS is visible in the evening sky, crossing through Ophiuchus, and is expected to brighten to 8th magnitude. The comet’s closest point to Earth, at 1.81 AU, occurs on July 14, and it reaches perihelion on December 19  at 1.797 AU.