Image Credit & Copyright: Gerhard Hudepohl of the Milky Way Galaxy and Zodiacal Light over one of the auxiliary telescopes at the Very Large Telescope (VLT) in the Atacama Desert, Paranal, Chile (Links below).
Who knows what we’re looking at here? Not the Milky Way Galaxy but that tall pillar of white light to the right side of the photo. Twice a year the orientation of the Earth places us at a prime vantage point to view a little known and in my opinion underappreciated phenomenon. Also known to the ancient Persian and Arabic astronomers as “False Dawn” or “Tall Twilight”, Zodiacal light is a vast towering pyramid of light whose point follows the zodiac constellations and the ecliptic into the night sky, reaching out for the Milky Way, spooky right? Here’s WHY and WHAT this is……..
In short, Zodiacal Light is a vast dust ring that lies in the inner solar system. It’s believed that it reaches out past the orbit of Mars and as the Sun sets in the west and rises in the east its glare scatters light of billions of microscopic dust particles, putting on a show for those wise enough to successfully hunt it. Those billions of interplanetary dust particles, too small for any telescope to resolve, pancake out along the plane of the ecliptic just as the planets and asteroid belts do. To this day astronomers are not 100% certain as to the complete picture but it’s believed that the Main Asteroid Belt contributed to only approximately 10% of its mass which in total is about the same mass as Mars’s moon Phobos. Most of the dust, it is believed comes from the blown off leftovers of Short Period Comets as well as material that created the solar system itself, 4.5 billion years ago.
The two best times of year to view Zodiacal Light in the northern hemisphere are roughly February through April about 90 minutes after sunset and again in September through November about 90 minutes before sunrise. For viewing in the southern hemisphere just use the opposite seasons. You can still spot them during some of the surrounding months as well but it’s tougher the further you get from the equinox as those are the two key “seasons” are when the ecliptic is highest in the sky. Another note here is that the closer to the equator you are the easier it will be to view because of the location and orientation of the ecliptic as well. The further you venture from the equator the more difficult it becomes to catch because of that angle. You will need to locate and get to the darkest skies you can find that have a low, clear eastern horizon (This includes the Moon as well so shoot for New Moon weeks). If you can’t easily see the Milky Way stretch overhead it isn’t dark enough. Your DSLR will pick up the light much better than your eyes, but that being said, it will also pick up the glow of the surrounding towns which may wash the Zodiacal Light out = DARK IS MANDATORY.
The September through November season; what that means is that prime viewing will be about 90 minutes, just before twilight when the ecliptic is closest to vertical. Really, just look for Jupiter as the gas giant will be in the thick of it. You can also view it after sunset in the west just after twilight but at that time the ecliptic is at a steep southward angle but you can still see it if it is clear, dark and your horizon is open.
The February through April season; is just the opposite as the ecliptic will be near vertical after sunset in the west, after twilight. When the Sun comes back around in the east before twilight the ecliptic will be at a steep angle once again. So here, a western view 90 minutes after sunset, just after twilight is your prime opportunity.
For my SOUTHERN HEMISPHERE friends, everything is opposite. September through November you will need a western view 90 minutes after sunset, just after twilight. In the February through April season prime viewing will be an eastern view 90 minutes before sunrise, just before twilight.
All in all just get out there and try to see it and or shoot it. Don’t take everything written here as concrete either; many amazing photos have come from months surrounding peak months. Use this as a guideline and see what your night sky is telling YOU!
Gerhard Hudepohl main site: http://www.atacamaphoto.com/sitemap1.htm
Time and Date article: http://www.timeanddate.com/astronomy/zodiacal-lights.html