Wyoming Skies: Long, deepening colors of twilight make July a month to remember

Stargazing in July hopefully promises warm nights in Wyoming. The highlight of July evenings is the prominent band of the Milky Way arcing across the dark skies. Along the Milky Way, you’ll spot the Summer Triangle and the Teapot of Sagittarius and Scorpius hovering over the southern horizon. Additionally, there are numerous deep-sky objects to study in a single night. To enhance the summer skies, two of the strongest meteor showers of the year streak overhead. While I consider July nights my favorite, as a student once pointed out, “you always say that,” I can’t deny it.

Begin your July evening by enjoying the long, deepening colors of twilight. As darkness falls, the first stars start to appear. Arcturus and Vega are the brightest stars overhead, followed by Altair and Deneb. Finally, ruddy Antares sparkles to the south. Less bright stars soon appear, allowing you to identify some constellations.

This month, eight objects in the evening sky shine at first magnitude or brighter. In order of brightness, they are Arcturus, Vega, Altair, Antares, Spica, Regulus, Deneb and Mars.

In July, the constellation Hercules is high overhead. The four stars forming the top of Hercules are known as the Keystone. If you point a telescope or binoculars to the west side of the Keystone, you’ll discover a magnificent globular star cluster called M13.

West of Hercules, you’ll spot a semi-circle of stars called Corona Borealis. Keep an eye on it this summer, as astronomers have been predicting since last fall that the “Blaze Star” will briefly appear. This star typically undergoes an outburst, known as a nova, approximately every 80 years, but it’s almost a year overdue.

Right next to Corona Borealis lies Bootes, a kite-shaped group of stars easily identifiable due to the brilliant star Arcturus. To find Arcturus, use a handy sky key that guides you to follow the handle of the Big Dipper and then “arc to Arcturus, then speed on to Spica.” This direct path leads you to the two bright stars, with Spica being the brightest star in Virgo.

East of Hercules, you’ll find Lyra, home to the bright star Vega, and Cygnus, which contains the well-known asterism known as the Northern Cross. The brightest star in Cygnus is Deneb. You’ll easily spot a large pattern of stars called the Summer Triangle. This triangle comprises the three brightest stars in three different constellations. Deneb, the most northern star, is in Cygnus, Altair, the most southern star, is in Aquila, and Vega, the star that forms the third star of the triangle, is in Lyra.

Looking south, you’ll spot the “Teapot” of Sagittarius and a fishhook-shaped group of stars forming the constellation of Scorpius. Both are situated along a prominent band of the Milky Way. If you follow the Milky Way upward in the sky, you’ll pass by Aquila, Cygnus, and end up at Cassiopeia in the northeast. Cassiopeia is easily recognizable, consisting of five moderately bright stars that appear as an M or W shape in the sky.

Returning to the Teapot above the southern horizon, you’ll quickly understand its name. It resembles an old-fashioned teapot, and the “steam” emanating from the spout is the Milky Way. Its spout also points in the direction of the center of our Milky Way galaxy.

What is the Milky Way, the radiant glow across a dark sky? When you gaze upon the Milky Way, you’re witnessing a spiral arms of our galaxy. It contains an immense number of stars, along with gas and dust, which blend together, creating a subtle, milky glow across the sky. The summer Milky Way is particularly prominent in a dark sky on summer evenings. If you use binoculars and follow along the Milky Way, you’ll discover a treasure trove of stars, star clusters and nebulae.

Most of the planets visible this month are found in the morning sky.

Mars descends more each evening, traversing the stars of Leo. The moon will visit Mars on July 28. Mercury will be low in the western twilight until mid-month. Keep an eye out for it about 30 to 40 minutes after sunset.

Early morning risers will have delightful spectacle this month. The brilliant planet Venus will be easily visible before dawn, with the bright planet Jupiter below it, and it’ll ascend higher each morning. Venus and Jupiter will pair up on Aug. 12. Saturn blends in with the first magnitude stars and is found in the southern sky at dawn. On July 16, the moon will pass by Saturn. Near Venus will be the glittering star cluster Pleiades, also known as the Seven Sisters. It’s a beautiful group of stars resembling a tiny dipper. Additionally, a thin crescent moon will be near Venus on July 21 and visit Jupiter on July 23.

On the morning of July 20, the moon passes in front of — and blots out — some of the stars of the Pleiades. They are best observed through binoculars.

And on July 3, Earth reaches its farthest point from the sun, known as aphelion. This distance is approximately 3 million miles greater than when we were closest to the sun, during perihelion, on Jan. 3, 2025. The tilt of the Earth plays a crucial role in determining our warmest months. In July, the Northern Hemisphere tilts toward the sun, allowing us to receive direct sunlight. On the other hand, in January, we are tilted away from the sun, resulting in reduced direct sunlight. The Southern Hemisphere experiences the opposite pattern, with summer being the time when they are closest to the sun and winter when they are farthest.