In a rare display, between now and late February, all the planets in the solar system, save for Uranus and Neptune, will be prominently displayed during the pre-dawn hours!
Set against the rising spring and summer stars before dawn we begin with Mercury, low in the southeast in Sagittarius and preceding the sun at its rising. Occurring on the morning of 2016 Feb 7, Mercury is fast approaching its greatest western elongation. GWE is the relative position of either of the inner planets’ (Mercury or Venus) orbits farthest from the sun to the west, as seen in our sky and therefore visible in the early morning, preceding the sun at its rising. The evening analog to this is the Greatest Eastern Elongation (GEE), the greatest easterly separation from the sun, following it after sunset. Still in Sagittarius and immediately to the west along the ecliptic we find brilliant Venus. Continuing west along the ecliptic into Ophiuchus, we find the venerable Lord of the Rings, Saturn, well placed to the northeast of the red supergiant star, Antares, the heart of Scorpius, the Scorpion. Continuing our scan along the ecliptic into Libra, we find Mars and then, last but not least, mighty Jupiter, set as a brilliant beacon in Leo. Jupiter is visible all night and by the time the sky waxes bright in the east, Jupiter will be west of the meridian; in fact, Jupiter transits the meridian before midnight and, with dawns morning light waxing bright, Jupiter is well placed, low in the west.
As it changes shape each night, our large natural satellite, the moon, will also add to the spectacle as it proceeds 12 degrees eastward along the ecliptic. With the moon in a different constellation, a new perspective is had perhaps, a new sense or insight into the heliocentric geometry of our solar system and its dynamics. Over the coming weeks, the sky as it presents itself during the early morning hours is a veritable planetarium in what lessons can be learned about our solar system and its dynamics; it is a planetary astronomer’s dream. A particularly beautiful combination of brilliant Jupiter, Mars, the waning gibbous moon along with the stars Spica, Arcturus and Regulus can be seen on the night of February 24th-25th, less than one month from today.
The 12 constellations of the zodiac are simply those constellations that reside along the ecliptic, the imaginary path described by the sun as it appears to move across the sky each day. There are actually 13 constellations of the zodiac, so your astrological birth sign is different (in most cases) than your astronomical birth sign. A more accurate identification of your birth sign would be the astronomical analog to what you’re so used to, your astrological. The ancient Greeks omitted Ophiuchus from the zodiacal constellations for a variety of reasons, most notably because of its basis in Egyptian mythology and lack of representation in Greco-Roman mythology. Nonetheless, it technically is a member constellation of the Zodiac and, as such, your “true” birth sign is probably not what you’ve been led to believe as you follow your daily horoscopes. Your true birth sign is actually one constellation to the west. If you were born in late October, for example, you are a Virgo, not a Libra.
You can explore this further and discover your true birth sign and much, much more by downloading a great, free digital planetarium for your desktop: Stellarium.
All graphics presented in this article were produced using Stellarium.