The planet show we have been enjoying over the last several months fades a bit for us in July. Yet good evening views of Mars and Saturn will be possible and the morning eastern sky will feature our two innermost planets, Venus and Mercury.
Mars may be found in the southwestern sky as soon as it gets dark all month. On July 1st it will be only 5 degrees (above and right) from Spica, the brightest star in Virgo. Its reddish-orange color will make a nice visual contrast with the blue-white color of this star. Only July 5th, the 1st Quarter Moon will be seen between Mars and Spica; being only one degree from Mars! Mars and Spica, due to Mars’s orbital motion, will appear to draw closer to each other all month. Indeed, they will be only one degree apart on July 12th! Thereafter, Mars will move past Spica throughout the month.
Saturn may be found east – or to the left – of Mars. They will appear to draw closer to each other too, throughout the month, dropping from 28 degrees of separation down to just 12 degrees. In late August they will be only 4 degrees apart from each other —— something to look forward to seeing then.
Mercury makes a brief appearance in the pre-dawn sky of July and reaches greatest eastern elongation angle from the Sun on the morning of July 12th. What this means is that it will be about 21 degrees in front of the Sun and about 7 degrees above the east-northeast horizon, 45 to 60 minutes before sunrise. Mercury will also be just to the lower left of brighter Venus then, which will be a guide to finding the dimmer Mercury. We will, however, need a clear, un-obstructed view down to the horizon to see Mercury since it remains quite low and it will be seen in a sky already getting lit-up by approaching dawn.
Summer nights provide comfortable temperatures for viewing, but because summer day lengths are greater, it does not get completely dark until nearly 9:30 pm during July. Moreover, the warm summer air can hold more moisture than cooler air, and often does. It is what we call humidity. And humidity can sometimes give us hazy skies, which can muffle the lights of stars we seek. Despite this, when it is clear, and we can avoid street and house lights around us, the summer Milky Way spread out before us in regal splendor as we look toward the center of it in July.
Beginning due south between Scorpius and Sagittarius, the Milky Way appears to arch up toward the zenith, through Aquila the Eagle, past Cygnus the swan, and then descends toward the northeast through Cassiopeia the Queen, and on to Perseus the hero, and down to the northeast horizon.
Every summer since I was 10, I have looked at the Milky Way through binoculars, slowly tracing the path I just described, never tiring of the splendid, wide field view I see. Countless more stars and glowing gases than can be seen with the unaided eye are revealed, giving just a hint of the the vastness of space. Try it yourselves. You will be hooked!
Moon phases: 1st quarter/July 5; Full/July 12; Lat Quarter/ July 18; New/July 26.