When guests visit the local observatories, staff astronomers always look to impress them with great views of the Moon, Jupiter, Saturn and Mars when any of these worlds are observable. The wealth of detail visible through each facility’s telescopes can awaken the sense of awe within children and adults alike. What child hasn’t marveled at the Moon’s vast craters? Who hasn’t watched the parade of Jupiter’s Galilean moons orbiting this gigantic planet and not thought about Galileo’s first view of this phenomenal sight? We sky interpreters love to hear the oohs and aahs as folks get a glimpse of Saturn’s magnificent rings for the first time. And when dust storms on Mars don’t spoil the view of this desert-like world, who can’t help but wonder if life may exist beneath its surface? Any night amateur astronomers can introduce casual stargazers to these magnificent worlds is a wonderful experience.
However, while the afore-mentioned objects get most of the glory, there are two inferior planets of our solar system that are often neglected. No, they do not have any neuroses. Inferior is an astronomical term meaning these planets orbit between the Sun and the Earth. I’m referring to Mercury and Venus. Consequently, they do not stray far from the Sun in the sky from our Earthly perspective. Examine this brief video which explains what we observe. Whenever Mercury and Venus appear above either the eastern or western horizon these events are called elongations. Mercury can appear no more than a maximum of 28 degrees away from the Sun, while Venus can appear no more than a maximum of 48 degrees away from the Sun. Elevation above one’s horizon varies from one elongation to another.
Continue reading Observing the Inner Solar System: Mercury and Venus
Happy New Year everyone. Yet another year has passed into the history books, and I am once again presenting some of the astronomical highlights upcoming in 2020. While there are a couple of impressive upcoming events, any time the skies are clear and transparent many stargazers are enticed out under the vault of the heavens to explore our beautiful universe.
The winter months around Southern New England can be quite cold, and I for one need some incentive to spend much time outdoors observing the sky. Fortunately, the sky gods provide the Quadrantid meteor shower which peaks on the night of January 3-4. While this shooting star display can produce up to 100 meteors per hour during peak, a more modest 60 meteors per hour is likely under a moon-less sky. This shower also sports a very narrow peak of activity, only several hours in duration, that can easily be missed. However, if you have the time and can tolerate the usual cold temperatures, the Quadrantids don’t disappoint the well-prepared observer.
Continue reading Astronomical Highlights for 2020
As quickly as it started, 2019 will soon be in the history books. I for one am happy to see it go. A cloudy and rainy spring, hot and humid heat waves during the summer, then the EEE mosquito threat have conspired to prevent casual stargazers and amateur astronomers alike from enjoying the night sky and all the wonders it holds. It would be great if we could end the year on a high note, but the sky gods are not smiling down on us for December.
Though the Geminids are the best meteor shower of the year, peaking on the night of December 13-14, the Full Moon on the 12th will overwhelm all but the brightest meteors. To complicate matters further on the peak night, that bright moon will be sitting right in the middle of the Gemini constellation. While you won’t require my usual star map to find Gemini, the proximity of the Moon to the region of the sky from where the meteors appear to radiate (near Gemini’s brightest stars, Castor and Pollux), will certainly reduce your meteor count. .
However, one does not have to look directly at Gemini to catch a few of the brightest shooting stars. In fact, the Geminids are fairly bright and also have a reputation for producing exploding meteors called fireballs, My point: if the weather cooperates on peak night do not give up on the Geminids. You might just glimpse a few bright Geminids as they enter our atmosphere at 21.75 miles per second.
Continue reading Geminid Meteor Shower Mooned Out and Other Celestial Offerings
Venus and Mercury transits occur when these worlds, which orbit between the Earth and the Sun, can be seen to pass directly in front of the solar disk and transit across the face of our star. Why don’t we experience a transit of Venus or Mercury every time they pass between the Earth and the Sun (called inferior conjunction)? It all has to do with the orbits of these planets and our ever-changing viewing angle. Most of the time Venus and Mercury pass above or below the solar disk as seen from the Earth. This concept is simply stated here, but it took the greatest astronomical minds of the past to solve this great mystery. The process took much observation, dedication and deduction to determine the solar system design and the celestial mechanics that govern its motion.
Venus transits are rare astronomical events. They always occur in pairs, eight years apart. We last experienced transits of Venus in 2004 and 2012. Their immediate predecessors occurred back in 1884 and 1882. And the next pair won’t be until 2117 and 2125!
However, another planet can transit the Sun—Mercury. Though not as rare as Venus transits, transits of Mercury occur 12-13 times per century. The last one occurred on May 9, 2016 and it was observed in its entirety locally. The Mercury transit prior to that occurred on November 8, 2006, but in Southern New England we were clouded out. Unfortunately, the next one visible here after the upcoming November 11 event won’t be until May 7, 2049.
Continue reading Transit of Mercury: A Unique Astronomical Event November 11, 2019
First up for November is my reminder to be sure to set your clocks back one hour on Sunday, the 3rd. That’s when most of the United States switch back to Eastern Standard Time from Daylight Saving Time. The mnemonic is “spring ahead and fall back/behind”. Thank goodness for most of us it occurs on a weekend!
While the premiere astronomical event during November will be the transit of Mercury between the Earth and the Sun (which I will preview in a separate column), there are two meteor showers as well.
From November 4th thru the 6th watch the sky for no more than a half dozen or so Taurid meteors. These often very bright yellow fireballs (meteors that explode and fragment into multiple pieces) are fairly slow and enter our atmosphere at approximately 17 miles per second. Observe after midnight to increase your chances of seeing one. Look in the general direction of the constellation Taurus. To locate Taurus find the V-shaped pattern that defines the bull’s face, or locate the Pleiades — the Seven Sisters star cluster. A waxing gibbous Moon will overshadow all but the brightest of the meteors this year.
Continue reading November Meteor Showers