Tuesday, May 31, 2016

Tonight's Sky for May 31: Mars at its Closest and Brightest


Mars may have reached opposition about a week ago but it is actually today that it is at its closest to Earth. To see the Red Planet, simply head out and look Southwest as soon as the sky gets dark, it's the brightest object in that area of sky.

Sunday, May 29, 2016

Tonight's Sky for May 28: Third Quarter Moon

Today, the Moon, second brightest object in the sky, has reached the Third Quarter phase, which means that it is exactly 270 degrees around its orbit of Earth.

As for lunar mechanics, the Moon is always half lit. The reason we don't always see it as such is thanks to orientation in relation to us. Right now, with the Moon at a 90 degree angle relative to the Earth and Sun, we see the Moon as half lit and half dark, leading to the popular, erroneous phrase 'half Moon.'

After today, we will see less and less of the Moon as its lit side turns more away from us and heads toward a new lunar cycle.    

Thursday, May 26, 2016

Tonight's Sky for May 26: Be Alert for Aurora

Skywatchers living at high latitudes are being advised to be alert for aurora tonight and into tomorrow morning as the Sun will be entering a high-speed stream of solar wind. According to NOAA, there is a 40% chance of geomagnetic storms from tonight and into tomorrow morning. 

Tuesday, May 24, 2016

Tonight's Sky for May 24: First Helping of Steamed Cosmic Cheese


This morning, the Moon will appear above the Teapot's spout in the heart of Milky Way, which appears as if it were steam coming out of the spout. As for the cheese, who hasn't heard the old wives tale of the Moon being made of cheese?  

Monday, May 23, 2016

Tonight's Sky for May 23: Moon Meets Mars, Saturn


This morning, the Moon, Saturn, and Mars will be in a line in that order going from left to right low in the Southern predawn sky. Additionally, bright red Antares, whose name means 'rival of Mars' undoubtedly because of his red color, will be nearby, too.

Sunday, May 22, 2016

Tonight's Sky for May 22: Mars at Opposition

Tonight, the planet Mars, 4th from the Sun, will be at opposition. What does that mean? In short, if viewed from above, the Sun, Earth, and Mars would be in a straight line in that order, with Mars exactly opposite the Sun in the sky as seen from Earth. End result: Mars rises as the Sun sets and Mars sets as the Sun rises, meaning that Mars is up all night. 

Thursday, May 19, 2016

Tonight's Sky for May 19: Be Alert for Aurora

Skywatchers living at high latitudes are being advised to be alert for aurora tonight and into tomorrow morning as the Sun will be entering a stream of solar wind escaping from a coronal hole. According to NOAA, there is a 50-60% chance of geomagnetic storms from May 19-20.  

Wednesday, May 18, 2016

Tonight's Sky for May 18: Moon at Apogee

Tonight, the Moon is about as small as it will ever get thanks to the fact that the Moon is at apogee, a point in its orbit that is farthest from Earth.


What many people may not realize is the fact that the Moon (and all other celestial bodies) do not orbit their parent bodies in circles, but ellipses, which are slightly elongated circles. Result: any given day of an orbital period, any orbiting body will be at a slightly different distance from its parent body. As for the Moon, this variance in orbit amounts to about 20,000 miles.

As for tonight, the Moon will be about as far from Earth as it is going to get. When it comes to practical implications, the difference will be hard to notice with the naked eye to all but an experienced observer but, in a telescope, the difference will be obvious

Tuesday, May 17, 2016

Tonight's Sky for May 17: Mars Rises 9 Hours Ahead of the Sun

Tonight, Mars is rising 9 hours after the Sun, meaning that it is up most of the night come May as it nears opposition, which is set for the 22nd, which is not even a week away. 

Monday, May 16, 2016

Tonight's Sky for May 16: Be Alert for Aurora

Today, Earth is set to enter a stream of the solar wind emanating from a coronal hole. NOAA is advising skywatchers, especially those living at high latitudes, to be alert for aurora.  

Sunday, May 15, 2016

Tonight's Sky for May 15: Northern Lights of Historic Proportions (2005)

It was on this date in 2005 that a historic display of the Northern Lights took place. The best part: thanks to technology, we have day by day accounts of the event.

Everything started a few days before the big light show. At the time, we were on the downward trend for extremely strong sunspot cycle 23, which stands in stark contrast to current cycle 24, one of the weakest ever seen in recorded history. It was on May 13 that sunspot 759 erupted a M8 class solar flare accompanied by a coronal mass ejection (CME) that was hurled into space directly towards Earth. Interestingly enough, while there was an increased chance for geomagnetic activity, no one expected anything unusual because, after all, the flare was only a M8.

Boy, how everyone was wrong!


Then, on the night of Saturday and into Sunday (the 15th) morning, the skies over the United States erupted with brilliant displays of the Lights as far South as Florida and Arizona. Depending on location and atmospheric composition, the colors included reds, oranges, greens, blues, and even purples. It was on this night that yours truly saw his only display of Aurora. In my neck of the woods in Northeast Ohio, the Lights were a mix of violet and blue overhead, gradually blending into green curtains as they approached the horizon. I remember vividly being a bit dumbfounded as to what the lights were at first, only realizing that these were the Lights after a moment or so. First seeing them at around 4am, I stayed up until dawn, at which time the brilliant display was out-shown by the Sun.

Hopefully, such a sight will repeat itself soon, we're long overdue in these parts . . .  

Saturday, May 14, 2016

Tonight's Sky for May 14: Moon Meets Jupiter

Want to see the planet Jupiter but have no clue where to look? Well, tonight's your lucky night as the Moon will be parked right next to the planetary king. To see the show, simply go out this evening and spot t he Moon and that bright 'star' next to it, which is actually the planet. Binoculars and telescopes add to the fun here.

Wednesday, May 11, 2016

Tonight's Sky for May 11: Saturn Rises 8 Hours Ahead of the Sun

Tonight, Saturn is rising 8 hours after the Sun, meaning that it is up most of the night come May as it nears opposition, which is set for June.

Tuesday, May 10, 2016

Tonight's Sky for May 10: Jupiter Ends Retrograde for 2016

Tonight, Jupiter will appear stationary as seen from Earth as it ends its period of retrograde motion, or its apparent backwards movement, for the year. Why does this happen?It's all an optical illusion caused by a faster planet overtaking a slower one. A real life comparison is when passing a slower car on the highway when the car you're passing appears to fall behind you even though both cars are moving forward.   

Sunday, May 8, 2016

Tonight's Sky for May 8: Mars Rises 8 Hours Ahead of the Sun

Tonight, Mars is rising 8 hours after the Sun, meaning that it is up most of the night come May as it nears opposition, which is set for the 22nd, just about 2 weeks away. 

Saturday, May 7, 2016

Tonight's Sky for May 7: Young Moon


How thin of a
Moon have you seen? How about one that's just barely over a day old and only 3% illuminated? Well, if you have never seen a Moon this thin, this is your chance to do so as such a Moon will be making an appearance in this evening's sky just after sunset. 

To see the Moon, you'll need a good Western horizon. How good? One with less than 10 degrees of obstruction. To simulate this, hold your fist vertically at arm's length to simulate 10 degrees. Hint: if you can't think of a good location off-hand, scout out one during the day. Location found, head there at sunset and start looking, preferably with optical aid, and start scanning the sky. The Moon may not be visible at first, often seeming to suddenly pop into visibility as if it were flipped on like a light.

Believe me, when this happens, it's an exhilarating experience.


Friday, May 6, 2016

Tonight's Sky for May 6: New Moon

Today, the Moon, second brightest object in the sky, has reached the New Moon phase, which means that it is directly between the Sun and Earth, and thus invisible for us Earthlings as of now. 

As for lunar mechanics, the Moon is always half lit. The reason we don't always see it as such is thanks to orientation in relation to us. Right now, with the Moon directly between the Earth and Sun, e can't see any of its lit side.

After today, we will see more of the Moon each night as its lit side turns more toward from us and heads toward first quarter.

Thursday, May 5, 2016

Tonight's Sky for May 5: Old Perigee Moon


How thin of a Moon have you seen? How about one that's just barely a day before New and only 2% illuminated? Well, if you have never seen a Moon this thin, tonight's your chance to do so as such a Moon will be making an appearance in this morning's sky just before sunrise.

To see the Moon, you'll need a good Eastern horizon. How good? One with less than 3 degrees of obstruction. To simulate this, hold two fingers vertically at arm's length to simulate 3 degrees. Hint: if you can't think of a good location off-hand, scout out one during the day. Location found, arrive there about 15 minutes before sunrise and start looking, preferably with optical aid. The bad news: you'll have to hurry because, as soon as the Sun clears the horizon, you can forget about seeing the Moon.

Additionally, the Moon is at a point in its orbit called perigee, which means that it is at its closest to the Earth today, too. 

Wednesday, May 4, 2016

Tonight's Sky for May 4: Eta Aquarid Meteors Peak

]Tonight will mark the peak of the Eta Aquarid Meteor shower for this year, thus marking the climax for the 2-week event. Every April and into May, Earth passes through the stretch of space junk shed by Comet Halley, reaching the deepest concentration of debris tonight. According to some estimates, under ideal conditions (dark country skies), one can expect to see 10-15 meteors per hour. The reason the meteors are called Eta Aquarids is because the meteors seem to radiate from the constellation Aquarius, namely the region of its eta star. The best time to view the shower is predawn, as Aquarius is at its highest (though still rather low in the Southern sky) then.

To improve odds of seeing meteors, travel out of the city and to the country if you can. In the suburbs, just going from the front to back yard can make a dramatic difference as this will eliminate glare from those pesky street/house lights to a large extent.

Fortunately, this year's Delta Aquarid peak coincides with the New Moon. This means that there will be no natural light pollution to interfere with meteor watching this year.  

Tuesday, May 3, 2016

Tonight's Sky for May 3: Jupiter Due South at Nightfall

Want to see the planet Jupiter but don't know where to look? Well, come the stroke of midnight, it's just about due South. That known, head out at the prescribed time and look South and up. See t hat bright 'star?' Well, that's actually Jupiter. 

Monday, May 2, 2016

Tonight's Sky for May 2: Mercury Sets 1 Hour After the Sun

It may not be as easily visible as it was about a two weeks ago, but speedy Mercury is still setting an hour after the Sun, which means that it is still relatively easy (for Mercury) to spot after sunset, provided you have a horizon with less than 5 angular degrees of obstruction. Note: a fist held at arm's length simulates 10 degrees. 

Sunday, May 1, 2016

The May Sky 2016

With the arrival of May, the news is of a very mixed nature. First, the bad. While the lengthening of the days (and shortening of the nights) will slow, that is little consolation for astronomers as, by this time of year, the nights are getting rather short and staying up to view under dark skies is undeniably a chore for most. Ditto for getting up early for early bird observers. However, the good news is threefold. First, the rate of cloudiness will drop as it did last month. Second, May will finally bring consistently warm nights where bundling up is no longer a must. Third, at least at the start of the month, the bugs shouldn't be much of an issue, either.

Cool Constellations
By the time May arrives, most of the winter constellations are a memory. Still hanging around low in the West are Auriga and Gemini, but they won't last much longer. Also, barely circumpolar Cassiopeia is now just scraping the Northeastern horizon, too. By the time May comes around, there is no better time than now to use the handy Big Dipper signpost. Starting at the Dipper, follow the arc of the Dipper to bright orange Arcturus, alpha Bootes, and the brightest star in the spring sky. To the left of the kite-shaped Bootes, look for the arc of stars that is Corona, the crown. Next, speed onto blue Spica, alpha Virgo, and one of the brightest spring stars. Next, continue the curve to trapezoidal constellation Corvus, the crow. Finally, conclude in dim Crater the cup. Moving higher in the sky and looking in the South-Southwest, zodiac constellations Cancer and Leo are still well-placed, but this will be ending come next month. Speaking of Cancer, look just below the cosmic crab for a distinct ring of stars, the head of Hydra, the sky's biggest constellation, which snakes (sorry) through over 120 degrees of sky. For those who like to stay up later, there's mythological strongman Hercules and the Summer Triangle high overhead and, to the South, Ophiuchus, Serpens, Libra, and Scorpius are all starting to rise at a somewhat reasonable hour. By the time the sky starts to brighten, Vega is at Zenith, Sagittarius is due South, and the Great Square has reemerged in the East.

Planetary Perceptions
On the planet front for May, Mercury is the star, or planet, of the month. The first order of business should be to catch speedy Mercury in the dusk twilight. The little planet put on its best evening appearance of the year last month but, come May, it's quickly dropping out of the sky as it heads toward solar conjunction, from which it will appear as a morning object in the final days of the month just ahead of the rising Sun. The real big news here: on May 9, Mercury will transit the solar disc as it comes directly between the Sun and Earth, appearing as a tiny silhouette against the backdrop of the Sun thanks to lucky celestial geometry. The vast majority of the time, Mercury, as seen from Earth, passes above or below the Sun, but not this time. The next transit of Mercury will not occur until 2019. Moving into the night, Jupiter, which reached opposition on March 8 is extremely well-placed as the sky is getting dark as it just about crossing the meridian, and is thus at its highest. As an item of note, the sky need not be truly dark to get good views of planets. In fact, twilight commonly offers windows of steady air, making viewing planets at high power much, much easier. Later in the night, Mars is next to break the horizon, followed closely by Saturn. An item of note: these planets had been converging the past two months. Now, with Mars retrograding, period over, Mars is now putting sky between itself and Saturn, which will continue through June. Additionally, Mars comes to opposition the 22nd, meaning that it is directly opposite the Sun in the sky as seen from Earth, meaning that Mars is up all night. Moving to the immediate predawn sky, it will take eagle eyes and probably optical aid to spot Venus, which is barely visible at the start of the month and lost in the Sun's glare by mid May.




Tonight's Sky for May 1: May, Cross Quarter Day
Today is May Day and also a cross-quarter day. What is a cross-quarter day? It's the mid way point of any season and was, like the solstices and equinoxes, an important time for early civilizations as these days served as another natural way to divide up the year into periods of time, which became a matter of life and death with the advent of large scale agriculture around 5000BC.