Montana Night Sky

The highlight for the Montana night sky in July is provided by the brilliant planets Jupiter and Venus and the rapidly brightening Mars, which dominate the night sky.

Mars is making its closest approach to Earth since 2003 and will brighten from almost as bright as Jupiter at the beginning of the month to almost twice as bright as Jupiter by the end of the month.

Joining this show of planets are the other naked eye planets, Saturn and Mercury.

In early July, as the sky begins to darken, look for the brightest of the planets, Venus, high up in the western sky. As the sky darkens further, look for the innermost planet, Mercury, about 15 degrees to the lower right of Venus.

At the beginning of July, Venus sets around 25 minutes before midnight and Mercury sets around 10:45 p.m. By mid-month, Mercury is lost in the solar glare. By the end of the month, Venus sets almost 90 minutes before midnight. 

Of note for Venus is its close approach to Regulus, the brightest star in the constellation Leo, which occurs on July 9 when the planet and star will be only about a degree apart.

On the other side of the sky, the giant planet Jupiter shines brightly high up in the southwestern sky as the sky begins to darken. Jupiter is accompanied by the much fainter but brightest star in the constellation Libra. Jupiter sets about 2:40 a.m. as the month begins and about 12:40 a.m. at the end of the month.

As the sky darkens further, look for the ringed planet Saturn shining in the southeastern sky located above the teapot shape of the constellation Sagittarius. Saturn rises just before sunset as July begins and is well placed higher in the southeastern sky as the sky darkens by the end of the month. Saturn sets about sunrise as the month begins and about 3:30 a.m. when July ends.

Next up in the night sky is the biggest highlight of the July skies, the Red Planet, Mars. Mars rises about 11:15 a.m. at the beginning of July, when it is almost as bright as Jupiter. On July 31, Mars will be almost twice as bright as Jupiter, when it makes its closest approach to Earth since 2003 (which was its closest approach to Earth in almost 60,000 years). On July 31, Mars will also be closer to Earth than it will be again until 2035. Mars will shine brighter than Jupiter from early July until early September, so that for a period of two months, the only planet to outshine Mars will be the brilliant planet Venus.

With Mars rising earlier and earlier throughout July and only a few minutes after sunset as July comes to a close, for the entire month, Venus, Jupiter and Mars will all be visible in the night sky at the same time once Mars rises with the time when all three of these planets will be visible simultaneously increasing from a few minutes in early July to about 90 minutes by the end of the month.

As for the moon, the moon passes very close to Aldebaran, the brightest star in the constellation Taurus, on July 10. Look for the moon less than two degrees above Mercury on July 14. The next evening, the moon will be about two degrees to the right of Venus.  On July 20, the moon will be a little over three degrees above Jupiter. Look for the moon about two degrees to the upper right of Saturn on July 24. The moon is full moon on July 27.

For meteor shower watchers, the Delta Aquarid meteor shower takes place in July with a peak occurring before dawn on July 30.

With the moon being full just three days before its peak, to see meteors from this shower, its best to watch the sky once the moon sets and just before the sky begins to brighten toward dawn five days or more before this shower has its peak. That is because this shower is active for several days around July 30 and usually produces up to 10 to 20 meteors per hour and the moon sets almost 2 hours before sunrise on July 25 and earlier before that date.