Use the dazzling planet Venus to find the rather faint red planet Mars in the eastern predawn/dawn sky throughout the first week of October 2017. You may need binoculars to see Mars in the same binocular field of view with Venus. Fortunately, Venus and Mars will remain within a single binocular field for the next week or so, and these two worlds will come closest together on the sky’s dome on or near October 5. At that juncture, the two planets will only be 0.2o (2/5th the moon’s apparent diameter) apart.
The rising time of Venus and Mars into the morning sky varies worldwide. Given an unobstructed eastern horizon at mid-northern latitudes, the planetary twosome rises about 2 hours before sunrise. At temperate latitudes in the Southern Hemisphere, Venus and Mars come up in the east about one hour before the sun. Click here for an astronomical almanac to find out their rising times into your sky.
Venus, the third-brightest heavenly body after the sun and moon, outshines Mars by some 200 times. At present, Mars appears about as dim as it ever gets in our sky. That’s because the red planet lodges on the far side of the sun as seen from Earth; and moreover, Mars is only a few days shy of aphelion – its farthest point from the sun.
When Mars reaches opposition on July 27, 2018, this world will be approximately 6.5 times closer to Earth, and some 70 times brighter in our sky, than the red planet is now. At the July 2018 opposition, Mars will become the fourth-brightest celestial body to light up our sky, after the sun, moon and Venus. It’ll even be brighter than the king planet Jupiter, which usually rates as the fourth-brightest celestial body.
From here on out, look for Mars to climb upward each day, away from the glare of sunrise, and for Venus to fall closer to the rising sun day by day. In other words, watch for Mars to climb above Venus after a few more days.
The great conjunction of Venus and Mars in the eastern morning sky favors the Northern Hemisphere, although it can seen from the Southern Hemisphere as well. At mid-northern latitudes, get up at least 90 minutes before the sun to view Venus and Mars with either the unaided eye or an optical aid. Wishing you clear skies for the upcoming morning spectacle!