Blue Moon of May May 19, 2016Posted by aquillam in Astronomy, MichiganAstro, Urban Observing.
Tags: blue moon, Moon, observing, urban_observing
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The Moon will be full on May 21, and according to some, it’ll be a blue moon. Now if you’re familiar with the common definition of a blue moon, you’ll look at that date and say “hey, that can’t be a blue moon!” That’s because the modern, common definition of a blue moon is the second blue moon in a single month. Since it takes about 29.5 days for the Moon to go through a cycle of phases, the earliest date for a blue moon is the 29th of the month.
However, there’s another definition of blue moon: the third of four full moons in a season. The seasons start on an equinox or solstice, and are 3 months long, so they normally have 3 full moons. The current season (spring) started on March 20 at 12:30 AM and the first full moon after that was on the 23rd. Spring will end on June 20 at 6:34 PM, just 12.5 hours after the moon is full. If you’re curious for more, EarthSky has the next few blue moons (of both types) and references for further reading.
If you want to observe, the full moon is just about the worst time. The bright light washes out the sky around it, and the glaring noon (on the Moon) light makes it hard to see any surface features. So much for astronomy. However,if you like atmospheric phenomena or optical illusions, it’s great. A full moon is much more likely to give you a moon-bow, arcs, or rays. And if you like the moon illusion, only the June full moon will be better at tricking your mind.
Mars Opposition 2016 May 18, 2016Posted by aquillam in Astronomy, Galileoscope, MichiganAstro, Urban Observing.
Tags: astronomy, Mars, observing, Saturn, urban_observing
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On May 22, Mars will be at opposition. That means it’ll be opposite the Sun in the sky, so Mars rises as the Sun sets, and is out all night. It also means that Mars is relatively close to us. In fact, closest approach will fall on May 30. So don’t forget to take your binoculars or telescope on your Memorial day camp out!
One particularly nice aspect of the opposition is that Mars is in Scorpio. If you’re familiar with Scorpio, you know the brightest star goes by the name Antares. Ares is the Greek equivalent of Mars, so the name Anti-Ares, really means something like “opposed to Mars”, which most people interpret as “rival of Mars”. Personally, I like to think of it as “this is a star, as opposed to the planet Mars”, or more simply, “not Mars”. Usually, when Mars passes through Scorpio, you kind of need that reminder – the two objects look awfully similar, especially naked eye. During opposition however, there’s no mistaking the two. Antares is a poor rival, and definitely not Mars.
The Moon will be full on the 21, and passes through Scorpio the next two nights, so those aren’t the best days for comparing the star and planet. By the 24th it has moved out of the immediate area, and by the 30th you’ll have Moon-free observing most of the night.
As long as you’ve got your ‘scope or binoculars out, be sure to check out Saturn too. It’s headed for opposition on June 3. Hopefully I’ll have time to post about that at the end of the month.
Transit of Mercury May 9 2016 May 6, 2016Posted by aquillam in Astronomy, MichiganAstro, Urban Observing.
Tags: Mercury, solar, Sun, urban observing
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Phil Plait posted a very nice guide to the transit. It includes a long list of available webcasts, in case it’s cloudy or night where you are.
You’ll need magnification. DO NOT LOOK AT THE SUN WITHOUT APPROPRIATE FILTERS.
The transit runs 11:12 – 18:39 UT, or about 7:12 AM to 2:39 PM Ann Arbor time.
If you’re in SE Michigan, here’s a list of places you can go to observe the transit.