Thursday, March 31, 2016

Tonight's Sky for March 31: 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.   

Wednesday, March 30, 2016

Tonight's Sky for March 30: Saturn and Mars Rise 45 Minutes Apart, Span 8 Degrees

Last night's feature was the Moon meeting up with Mars and Saturn. Well, the Moon's still in the area and how about some specifics for the planets tonight? Mars has been retrograding, or appearing to move backwards relative to the stars (this is an optical illusion caused by Earth passing the slower Mars as both planets travel around the Sun), all month. At the start of the month, Mars rose about 1 ½ hour ahead of Saturn, now it's only rising about 45 minutes ahead of the ringed wonder. If you haven't been paying attention to the converging planets (or have been unable to do so because of clouds), it's a good time to start as the converging will continue for another month or so before Mars appears to reverse course again, this time stopping before appearing to move with the stars yet again and open up some distance between itself and Saturn.

Tuesday, March 29, 2016

Tonight's Sky for March 29: Moon Meets Mars and Saturn, Take 2


It's the second close meeting of the Moon, Mars, and Saturn of the month. At the start of the month, there was a similar meet up but, come the end of the month, things are going to look quite different. Why? Mars has been retrograding, or appearing to move backwards relative to the stars (this is an optical illusion caused by Earth passing the slower Mars as both planets travel around the Sun), all month. End result: Mars and Saturn are a lot closer together than they were just at the start of March. Additionally, Antares, whose name means 'rival of Mars,' undoubtedly due to the star's red color, is nearby, too.  

Monday, March 28, 2016

Tonight's Sky for March 28: Saturn Rises 6 Hours Ahead of the Sun

This morning, Saturn, 6th planet from the Sun, will be rising 6 hours ahead of the Sun, meaning that it is well up for observing by the time the sky starts to brighten in the morning, so why not take a look at it?

Sunday, March 27, 2016

Tonight's Sky for March 27: Be Alert for Aurora

Tonight and into early tomorrow morning, the Earth is expected to enter a stream of the solar wind, which will likely produce some geomagnetic activity, and thus aurora, also known as the Northern Lights. The higher your latitude, the better chances of seeing the Lights

Saturday, March 26, 2016

Tonight's Sky for March 26: Saturn Appears Stationary

Today, Saturn, as seen from Earth, will appear stationary in the sky and will begin its retrograde motion tomorrow. While not as obvious as, say, Mars, Saturn also appears to move with the stars, slow down, stop, and then begin to move counter to the background stars just like the Red Planet does. Why? It's an optical illusion caused by the faster Earth passing the slower Saturn. The same thing happens when you pass a slower car on the freeway when the car you pass appears to be falling behind you even though both are actually moving forward. The same is true of planets.

Friday, March 25, 2016

Tonight's Sky for March 25: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

Thursday, March 24, 2016

Tonight's Sky for March 24: Moon Meets Spica


Want to see Spica, alpha star of zodiac constellation Virgo but don't know where to look? Well, today's your lucky day as the Moon will be parked right next to the star. To see the show, simply go out in the predawn sky and find the Moon. That bright star next to it? That's Spica. 

Wednesday, March 23, 2016

Tonight's Sky for March 23: Mercury at Superior Conjunction

Today, the planet Mercury has reached superior conjunction. What does that mean? In layman's terms, Mercury will be directly opposite the Sun as seen from Earth in a Mercury, Sun, Earth alignment. End result: the planet will be at its worst point for viewing. Unfortunately, unlike inferior conjunctions wherein a planet moves directly between the Sun and Earth, superior conjunctions result in longer periods of invisibility but, in the case of speedy Mercury, the word 'long' is very relative

Tuesday, March 22, 2016

Tonight's Sky for March 22: Full Moon

Tonight, the Moon will reach its full phase, which means that, as seen from Earth, it is directly opposite the Sun in the sky as seen from Earth and is at the half way point in its current orbit.


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, when the Moon is opposite the Sun and on the far side of Earth, we can see all of its lit side, which is why it appears to be “full.” In the coming nights, we will start to see less of the Moon as its lit side starts to turn away from us as seen from Earth and heads toward Third Quarter. 

Monday, March 21, 2016

Tonight's Sky for March 21: Moon Meets Jupiter

Want to see the planet Jupiter but have no idea where to look? Well, no problem because, tonight, the Moon will be parked right next to Jupiter, largest planet in the solar system and fifth from the Sun. To see the show, simply go out tonight and look up to find the Moon. Moon found, notice t hat bright 'star' very close to it? Well, that 'star' is actually Jupiter. For more fun, turn a pair of binoculars on it to see the 4 large moons discovered by Galileo in 1609 or a telescope to see the cloud patterns on the planet itself.

Sunday, March 20, 2016

Tonight's Sky for March 20: Vernal Equinox (First Day of Spring)

For anyone not keeping track of the calendar, spring arrives today, which begs a question: why do we have seasons at all? Answer: it all has to do with the Earth’s 23 degree tilt.

If the Earth were spinning on its axis with no tilt at all, everyone would be treated to days of identical length every day of the year, with latitudes nearer the equator having longer days than those nearer the poles. However, with the tilt, the angle of the Earth relative to the Sun changes as or planet moves about its orbit. On the Vernal Equinox, the Sun will rise/set exactly due East/West and the day and the night will be exactly 12 hours long (Equinox means 'equal night').

After the Vernal Equinox, the lengthening of the days will continue (for us in the Northern Hemisphere) until the Sun finally reaches its most Northerly rise/set on the Summer Solstice, the longest day of the year, which is around June 20. From that point on, the Sun will only get weaker, once again having an Equinox, the Autumnal, around the 20th of September before culminating in its most Southerly rise of the year, the Winter Solstice, around December 20.

Friday, March 18, 2016

Tonight's Sky for March 18: Moon Meets the Bees and Snake



Tonight, the Moon will be near a pair of objects that herald the changing of the seasons from winter into spring: the cosmic snake and bees. The key to the whole show is the Moon. Luna found, look below it for an oval shape of 5 stars, which represent the head of Hydra, the mythological water snake that is also the largest of all 88 constellations, snaking (sorry) its way through over 100 degrees of sky. Hydra found, hop back up straight to the Moon and, now grabbing binoculars, to a spot about the same distance above the Moon that Hydras head was below. If you're on target, you'll see a fuzzy patch of sky in small binoculars and even individual stars in large ones. What is this patch? It's the Beehive Cluster, also known as M44, one of the largest open clusters in all the sky. 

Thursday, March 17, 2016

Tonight's Sky for March 17: The Snake St. Patrick Missed

Today is St. Patrick's Day, which celebrates St. Patrick, patron saint or Ireland who, among other things, supposedly drove all the snakes from the land. 

Unfortunately, St. Patrick missed the biggest snake of all: one that spans over 100 degrees of sky.

Hyrda the water snake was the mythological snake Corvus the crow brought back to Apollo instead of a cup of water (see also:
constellations). Enraged, Apollo flung the snake (as well as the bird and empty cup) into the sky. To find Hydra, look below Cancer for a circle of stars that represent the snake's head. From there, go East, snaking (sorry) through the sky to Alphard, alpha star and heart of the snake, before continuing until the serpent's tail, which lies just West of Libra.


Wednesday, March 16, 2016

Tonight's Sky for March 16: Be Alert for Aurora (Again!)

For the second time in a week, high-latitude dwellers will have a good chance at seeing aurora, also known as the Northern Lights. Yesterday, Earth entered a stream of the solar wind, which sparked spectacular aurora displays last night. As for tonight, NOAA is forecasting a 60% chance of a G-class geomagnetic storm today, too. 

Tuesday, March 15, 2016

Tonight's Sky for March 15: First Quarter Moon

Today, the Moon, second brightest object in the sky, has reached the First Quarter phase, which means that it is exactly 90 degrees around its orbit of Earth and is one quarter finished with its current orbit.. 

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-Sun line, we only see half of the 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 Full in a week. 

Monday, March 14, 2016

Tonight's Sky for March 14: Pi Day

Today is Pi Day, which serves to celebrate the ratio of a circle's diameter to its circumference, which just happens to be a relationship of 1 to 3.14, hence why we celebrate on 3/14 of every year. Pi Day originally began as a day to celebrate and promote math education but, over time, science teachers have come to embrace it, as well.

Sunday, March 13, 2016

Tonight's Sky for March 13: Early Morning Observing

While astronomers across the nation (except Arizona and Hawaii) are bemoaning having to stay up an hour later to view the night sky at the tail end of the day, the fact that there is a short, key word 'short,' window of time with an extra hour of morning darkness should not be overlooked. So, rather than complaining about having to stay up late, why not take the time to enjoy the morning sky?  

Saturday, March 12, 2016

Tonight's Sky for March 12: Spring Forward for Daylight Savings Time

At 2am tomorrow morning, the time change will place as America is set to spring ahead an hour as Standard Time is to be replaced with Daylight Savings Time, which will run through the first week of November. For most people, this will mean setting the clock ahead an hour before bed tonight. While most lovers of the great outdoors will rejoice, astronomers will not as, thanks to the time shift, dark skies will arrive an hour later than “normal.”

Friday, March 11, 2016

Tonight's Sky for March 11: Be Alert for Aurora

This morning, a solar flare expected to miss Earth actually made a direct hit, sparking a moderate geomagnetic storm, and hence aurora. While the storm is starting to subside, high latitude sky watchers are advised to remain alert for aurora tonight. 

Thursday, March 10, 2016

Tonight's Sky for March 10: Moon at Perigee

Tonight, the Moon is about as big as it will ever get thanks to the fact that the Moon is at perigee, a point in its orbit that is closest to 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 close to 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.


Wednesday, March 9, 2016

Tonight's Sky for March 9: True Young Moon


How thin of a Moon have you seen? How about one that's under a day past new and less than 2% 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 5 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.

Monday, March 7, 2016

Tonight's Sky for March 8: Jupiter Reaches Opposition, New Moon

Tonight, the planet Jupiter, 5th from the Sun, will be at opposition. What does that mean? In short, if viewed from above, the Sun, Earth, and Jupiter would be in a straight line in that order, with Jupiter exactly opposite the Sun in the sky as seen from Earth. End result: Jupiter rises as the Sun sets and Jupiter sets as the Sun rises, meaning that Jupiter is up all night.


In addition, the Moon is at new phase today, too. 

Sunday, March 6, 2016

Tonight's Sky for March 7: Old Moon Meets Venus


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.


The good news: Venus is very close to the Moon, as in that they will appear in the same binocular field close, which is a huge help.

Tonight's Sky for March 6: Valentina Tereshkova Born (1937)


It was on this date in 1937 that Valnentina Tereshkova, the first woman to fly into space, was born in the village of Maslennikovo. In her early life, Tereshkova was a textile worker before she became interested in skydiving. Following Yuri Gagarin's flight in April, 1961, it was decided that, having launched the first man into space, the Soviets should have a new goal:” launch the first woman into space. Beating out hundreds of other applicants and the other 4 finalists, Tereshkova launched into space aboard Vostok 6 on June 16, 1963. In all, Tereshkova would spend 3 days in space, orbiting the Earth 48 times, logging more orbital time than all the American astronauts up to that point combined.

However, there was an irony to Tereshkova's flight: the first female astronaut corps would never fly another member and would be itself disbanded in 1969. It would not be until 1982 when another woman would enter space.

Saturday, March 5, 2016

Tonight's Sky for March 5: Be Alert for Aurora

NOAA is forecasting a 50% chance of high-latitude aurora, also known as the Northern Lights, tonight into tomorrow morning when a stream of solar wind reaches a co-rotational interaction region (CIR). In layman's terms, this is a place where incoming plasma piles up, which often sparks displays of aurora.

Friday, March 4, 2016

Tonight's Sky for March 4: Saturn Rises 5 Hours Ahead of the Sun

This morning, Saturn, 6th planet from the Sun, will be rising 5 hours ahead of the Sun, meaning that it is well up for observing by the time the sky starts to brighten in the morning, so why not go out and take a look at it?

Thursday, March 3, 2016

Tonight's Sky for March 3: Venus Rises 1 Hour Ahead of the Sun

Want to see Venus, second planet from the Sun and third brightest object in the sky? Well, you'd better hurry up as the 'morning star' is sinking ever lower in the predawn sky to the point that it is now rising just an hour ahead of the Sun, meaning that it will be very close to the horizon, too. As the weeks progress, Venus will only get lower and lower until it reaches solar conjunction (and thus invisibility), which is set for June.

Wednesday, March 2, 2016

Tonight's Sky for March 2: Moon Meets Saturn


Want to see Saturn but have no idea where to look? Well, today's your lucky day as Saturn will be parked right next to the Moon this morning. To find Saturn, simply go out in the predawn hours and find the Moon and the bright 'star' next to it, which is, in fact, Saturn. Additionally, Mars and Antares (whose name means 'rival of Mars') are nearby, too. 

Tuesday, March 1, 2016

The March Sky and Tonight's Sky for March 1: Third Quarter Moon

With the month of March upon us, the lengthening of the days will be at its most noticeable as the Sun moves fastest near the equinox, which occurs on the 20th of the month. Besides the rapidly shortening nights thanks to the lengthening of the day, another dramatic loss in dark sky time will come on the second Sunday of the month (the 13th), which is when Daylight Savings Time returns. Needless to say, by month's end, there will be far less opportunity for observing as nightfall will come a lot later than it did at the start of the month. However, at least for a short while, there will be an extended window for morning observing with an extra hour of darkness at the start of the day.

Cool Constellations
At the start of March, the first order of business should be getting a last look at the winter constellations under dark sky conditions as, with the advent of DST, most will be low in the Southwest come nightfall and, unless one has a good horizon, too low to observe very well. The early-month, early-evening observing list should include Cassiopeia, Cepheus, Perseus, Orion, Canis Major, and Canis Minor. A few other winter constellations, including Auriga, Taurus, Gemini, and the Pleiades are still reasonably well-placed, though. As Orion was to winter, the Big Dipper is to spring in that it is a signpost to the stars. 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, zodiac constellations Cancer and Leo are well-placed as well. 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 late (or get up extremely early), there's mythological strongman Hercules and the Summer Triangle high overhead and, to the South, Ophiuchus, Serpens, and Scorpius

Planetary Perceptions
On the planet front, you'll need to be an early bird to catch 4 of the 5 naked eye planets. The one exception: Jupiter, which reaches opposition on March 8. What does this mean? As seen from Earth, Jupiter is opposite the Sun in the sky, meaning that Jupiter is up all night from sunset to sunrise. Moving into the night, Mars is next to break the horizon, albeit in middle of the night, followed by Saturn. An item of note: Mars is clearly converging with Saturn as Saturn was rising about 2 hours after the Red Planet at the start of March but, by month's end, they will be rising within 45 minutes of each other. As an interesting note, the Moon will make a pair of close passes of these two planets, on the mornings of the first and 29th. Try and see both events as one will clearly be able to see how much closer the planets are with the Moon in the picture. Moving to the immediate predawn sky, Venus hangs very close to the predawn Eastern horizon all month. As for speedy Mercury, it will disappear from the morning sky early month before making a sudden reappearance as an evening object the last week of March as it heads toward its best evening appearance of the year in mid April. Last but not least, there's a true Young Moon (under 24 hours past New) visible at dusk on the 9th.



Tonight's Sky for March 1: 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.