July will be an interesting month in the sky. Venus will be the only evening planet, but it will be dazzling bright low in the west. Although it is moving fast in its orbit, from our perspective on the also orbiting Earth, Venus will show very little movement. However, during the first part of the month the gap between Venus and Regulus, the brightest star in Leo (the Lion) that will be above it, will get smaller until they pass each other on June 7-9. Since stars are motionless in the sky, Regulus will appear to move closer to Venus because the orbital motion of Earth changes our perspective. After passing Venus, Regulus will drop quickly as Earth leaves it behind. Leo will be lost in the twilight glow by the end of the month

During July, the “fish hook” shaped constellation Scorpius (the Scorpion) will dominate the southern sky. Although it never gets very high above the horizon, Scorpius will be at its highest soon after it gets dark. When the constellation is fully in view in a dark sky, you will see that the “fish hook” and the row of three stars at a right angle to its upper end contain the largest number of fairly bright to bright stars of any northern constellation, making it one the best sights in astronomy.

While you are enjoying the starry field of Scorpius, if you want to see another of the best sights in astronomy, the front three stars of Scorpius point far to the northeastern sky to the general area of Cygnus (the Swan). The brighter stars of Cygnus form the shape (or asterism) of the Northern Cross, and the brightest star, Deneb, represents the top of the cross and the tail of the swan. A line of dimmer stars extending generally southward form the swan’s body. The foot of the cross is the star Albireo that is also the swan’s head. A short distance from the tail, two fairly bright stars on each side of a body star form the cross’s arms or the inner parts of the swan’s wings. The entire constellation is nestled within the countless stars of a dense part of the Milky Way, which gives us the awesome sight of the starriest field in the northern hemisphere visible to the naked eye.

As an additional help in locating Cygnus, Deneb is one of three bright stars that make up the Summer Triangle. The other stars are much brighter Vega in the tiny constellation Lyra (the Harp or Lyra) to the upper right (or southwestward) of Deneb and Altair in the constellation Aquilla (the Eagle), a farther distance to the right (or southeastward) of Deneb. The body of the swan extends into the Summer Triangle with Albireo almost in line with Vega and Altair.

Observing Highlights

July 6: The Earth will be at its farthest point from the Sun showing that warm summers are not caused by the distance to the Sun.

July 7: The Moon will lead Saturn into the sky at about 1:00. It will follow Saturn on the 8th. In the evening sky, brilliant Venus will be to the right of Regulus, the brightest star in Leo (the Lion).

July 9: Venus and Regulus will be at their closest, with Regulus just above Venus. Binoculars may help.

July 16 : The crescent Moon will be close to Regulus, the bright heart of Leo (the Lion), and to the lower right of Venus.

July 17: The crescent Moon will be to the right of Venus.

July 18 : Star Party sponsored by Grout Museum & Black Hawk Astronomy Club, Prairie Grove Park, Waterloo, 9-10:30.

July 22 : The Moon will be below Spica, the brightest star in Virgo (the Maiden).

July 23 : The Moon will be to the right of Antares, the bright reddish heart of Scorpius (the Scorpion). The moon will move in its orbit and be much closer to the left of Antares on the 24th.

July 28 : In the northeastern sky, the nearly full Moon will form a long line with two bright stars of the Summer Triangle, Altair in Aquila (the Eagle) and then Deneb in Cygnus (the Swan). To the upper right of Deneb and farther to the upper left of Altair will be the Summer Triangle’s brightest star, Vega in Lyra (the Harp or Lyre), that will lead the other stars across the sky.