Wednesday, August 31, 2016

The September Sky for September 1-13

The coming of September also signals the arrival of the Autumnal Equinox, which means that, by month's end, the night will once again be longer than the day. Also, with the equinox upon us, the most dramatic differences in solar movement (and thus length of day) will also occur, which means that, at least at the start of the night, the September sky is not all that different than it is in August.. During the course of the month, we will lose a lot of daylight. In all, the earlier nights combined with the lingering presence of the summer stars and summer heat makes for what is arguably the best time for astronomy in the entire year.

Cool Constellations
With the advent of September, the spring constellations are rapidly saying goodbye, with Virgo the next major constellation to disappear. Also getting low in the Southwest is Libra and Bootes and Corona are now just about due West at nightfall. In the North, the Big Dipper continues its dive, flattening out as it starts to approach the horizon. Perhaps the best part of the September sky is that one doesn't need to stay up late to see all the best sights of summer. At nightfall, Hercules is still near zenith, the Summer Triangle (Lyra, Cygnus, and Aquila along with hangers-on Saggita and Delphinus) is at zenith, Scorpius is due South with Ophiuchus and Sagittarius on either side, both still well-placed for observing. Also, the Milky Way is at its best positioning right after nightfall, too. For people who like to stay up late (or get up extremely early) a fall preview in the form of Pegasus, Pisces, Cetus, Andromeda, Aries, Capricorn, Aquarius, and even Perseus is on tap in the wee hours of the morning while, by month's end, the bright stars of winter in the form of Orion, Auriga, Taurus, and Gemini are visible, too.

Planetary Perceptions
With the arrival of September, changes are coming in the planetary world. First, Jupiter, which has been up seemingly forever, will disappear into the Sun's glare by mid month and will remain invisible for the remainder of September, reaching solar conjunction on the 26th. Moving slightly later Saturn and Mars will continue to separate this month after Saturn assumed the lead position last month. It should be noted that time to catch these outer planets under dark skies is limited thanks to the plane of the ecliptic, which is at its lowest position for prime time viewing all year. Staying with the evening theme, Venus will continue to hang extremely low in the Western sky all month. The real treat for September is in the morning as Mercury will be putting on quite a show in the morning come the end of the month. Look for it to emerge from the predawn glare around the 15th and it should be easy to spot by the 20th. On the morning of the 29th, there is a spectacular conjunction with the Old Moon, so circle your calendars for this one.

Tonight's Sky for September 1: 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.
Tonight's Sky for September 2: Young Moon Meets Jupiter, Venus
It may be two days since New Moon but the Moon is making its first appearance in the dusk sky tonight thanks to the flat ecliptic. However, the wait is worth the while as the thin crescent Moon will be parked very close to both Jupiter and Venus.

To see the show, head out after sunset and look extremely low in the West to spot the Moon. Luna found, look for two bright 'stars' nearby, which are actually Venus and Jupiter, Venus being the brighter and Jupiter the dimmer. Interestingly enough, these are the three brightest objects in the night sky-all within a few degrees of each other.

Tips: get optical aid in the form of binoculars. Yes, Venus and Jupiter are bright, but they're so close to the Sun that they may even be able to spot with the naked eye. Second, you'll need a good horizon with less than 5 (3 fingers held together at arm's length) degrees of obstruction, so scouting out a location in advance may be a good idea.
Tonight's Sky for September 3: Jupiter Sets 30 Minutes After the Sun
Anyone wanting to catch Jupiter had better hurry as the planetary king is setting just 30 minutes after the Sun as of this evening. To see Jupiter, grab a pair of binoculars and scan low in the Western sky.
Tonight's Sky for September 4: Saturn Sets 4 Hours After the Sun, Mars 1 Hour Later
It's not only Jupiter that's rapidly going away for the season, but Saturn, followed by Mars, are also rapidly approaching twilight's last rays, too. As of tonight, Saturn sets a 4 hours after the Sun with Mars following roughly 1 hour later. While 4 and hours don't seem all that urgent, they are this time of year as the ecliptic is at its lowest point for prime time viewing all year, which makes for some extremely low planets.
Tonight's Sky for September 5: Teapot Due South at Dark
You know it's late summer when the Teapot is due South at dusk. To see the cosmic kettle, go out as the sky is about half way to dark and look due South to find the relatively bright (2
nd magnitude for the most part) shape of stars resembling a teapot. Having trouble locating it? If you live under a relatively dark sky? You're in luck as you can find the Teapot by following the Milky Way down to the horizon as the galactic plane appears to be steam coming out of the spout.
Tonight's Sky for September 6: Apogee Moon
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


Tonight's Sky for September 7-8: Moon, Saturn, Mars, and Antares
Tonight and tomorrow night, there will be a 4-body cosmic meet-up in the Southern sky as the Moon, Mars, Saturn, and Antares will all be in the same small area of sky both tonight and tomorrow. For tonight, the 3 solar system bodies will form a line going left to right of Mars, Saturn, and the Moon with Antares slightly below. Tomorrow, the Moon will shift East (left) and appear directly above Saturn, making for a vertical Moon, Saturn, Antares line with Mars off to the side.

As an interesting aside, 'Antares' means 'rival of Mars' and, with the two bodies so close together, it is easy to see why as both display a very obvious shade of red and, when they're near the same brightness (Mars varies in brightness as it travels around the Sun), it can be easy to see how they can be confused with each other. AS for now, Mars is about 1 magnitude (roughly 2.5 times) brighter than Antares.

Tonight's Sky for September 8: 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.


Tonight's Sky for September 9: Viking 2 Launched (1975)
On this date in 1975, NASA launched the second of its Viking Mars probes. At the time, these were, by far, the most advanced planetary science missions ever attempted by the space agency. Consisting of an orbiter and a lander, the pair of Vikings revolutionized our ideas about Mars. When the first close-up images of Mars were captured in 1965, long-held hopes of an Earth-like planet were dashed when Mariner 4 returned two dozen images of a barren planet.

Fast forward a decade.

When the Vikings arrived at Mars, they revealed a world that was, to say the least, tantalizing. For starters, the landscape was surprisingly Earth-like as there were mountains, volcanoes, and, most importantly, river valleys and other features that were clearly created by long-gone water. Unfortunately, while providing more data about Mars than all previous missions combined, the landers' inability to find any organic compounds was regarded by the general public as a disappointment, so much so that NASA would not return to Mars for another 2 decades.


Tonight's Sky for September 10: Saturn Rises 1 Hour Before Mars
Remember how for all year Mars led Saturn through the night sky? Well, that changed last month when they switched positions and now, not even a month later, Saturn is rising 1 hour ahead of the Red Planet.
Tonight's Sky for September 11: Mars Global Surveyor Arrives at Mars (1997)
It was on this date in 1997 that the Mars Global Surveyor mission arrived at the Red Planet. Launched for Mars in On November 7, 1996, scientists had high hopes for this mission, especially thanks to its coming on the heels of the failed Mars Observer, which was lost in 1993. The goal: study Mars from the top of its barely-there atmosphere down to its surface and, for the first time, create a global map of the planet. Unlike Observer, Surveyor performed flawlessly, operating in Martian orbit for over 9 years. During that time, Surveyor mapped the planet, analyzed its atmospheric and surface composition, and scouted out possible landing areas for future surface missions among many other achievements.

Tonight's Sky for September 12: Venus Sets 1 Hour After the Sun
Tonight, Venus is setting an hour after the Sun, as hard as that is to believe. Why? The ecliptic plane is at a very low angle relative to t he horizon, which means that the planet is not very high. This is in contrast with Mercury, which is set to make an excellent appearance in the morning at month's end. The difference? When Mercury is up, the ecliptic will be almost perpendicular to the horizon, which makes for a much higher planet.
Tonight's Sky for September 13: Mercury at Inferior Conjunction
Want to see Mercury? Well, forget about it tonight as the speedy first planet from the Sun will be at inferior conjunction. What does that mean? In layman's terms, Mercury will be directly between the Earth and Sun in a Sun, Mercury, Earth alignment. End result: the little planet will be at its worst point for viewing. So, while this is more of a what not to see tonight event, mark this date on your calendar as we all will soon see how the planet again in the coming days (yes, days)!   

Wednesday, August 24, 2016

Tonight's Sky for August 25-31

I'm back, but still with no Internet of my own, which means having to rely on bumming off of others' free wi-fi wherever I can get on it. If that weren't a pain enough in itself, having to drive  6 miles to the nearest town (and hotspot) all while trying (and failing) to remember your laptop, doesn't help either. Hopefully I will soon have Internet of my own and the daily posts will resume. Until then, look for huge chunk posts like this. Clear skies!

Tonight's Sky for August 25: Moon Meets the Hyades

This morning, the Moon will be amongst one of the closest to Earth star clusters: the Hyades, located in the zodiac constellation of Taurus. To see the show, go out and find the Moon. Moon found, look around the Moon to spot a 'V' of stars, set off by bright orange Aldebaran, that constitute the brightest stars of the cluster and also the bull's nose. To see more stars, grab a pair of binoculars.
Tonight's Sky for August 26: Deneb at Zenith at Midnight
Tonight, Deneb, the brightest star in the constellation of Cygnus the swan, will be just about directly overhead (at zenith) tonight, which means that all one needs to do in order to see it is go out and look straight up at midnight. Besides Deneb and Cygnus, the whole Summer Triangle (consisting of Lyra's Vega, Deneb, and Aquila's Altair) is also straight up, as is the summer Milky Way. Trying to spot t he Milky Way straight overhead is a good test of how good (or bad) light pollution is in your area.

Tonight's Sky for August 27: Venus and Jupiter at their Closest
Tonight just after sunset, Venus and Jupiter, the two brightest planets in the solar system, will be making their closest pass, coming within 4arc minutes of each other, in half a century. To see the show, head out 30-45 minutes after sunset and look low in the Western sky, with optical aid being a good idea here as to appreciate the split. Without the optical aid, this is a great way to test your eyes as neither planet should be much of a struggle to spot in regards to the fading twilight. A good Western horizon, though, is a must!

Tonight's Sky for August 28: Venus and Jupiter, Take 2
If you missed yesterday's close pass of Venus and Jupiter, don't worry, they may not be quite as close tonight but they're still pretty close to each other, and still worthy of a look.

Tonight's Sky for August 29: Fading Sunlight
It's less than a month from the Autumnal Equinox, which means that the Sun is setting earlier and earlier each night, now at a very noticeable pace. Why? The Sun moves along the horizon nearest the equinoxes, resulting in the quickest shortening/lengthening of the day depending on the time of year. Needless to say, if you enjoy daytime outdoor activities, your time is starting to become very limited by now!

Tonight's Sky for August 30: Thin Crescent
While not as spectacular (for its lack of illumination) as tomorrow morning's less than 1% illuminated Old Moon, this morning's thin crescent (4% illumination) is still quite a sight and, to the relief of many, an easy one to see. Simply look East in the predawn sky for a thin crescent Moon, that's it, no optical aid needed!

Tonight's Sky for August 31: Old 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.





Monday, July 18, 2016

Tonight's Sky for July 18: 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. 

Sunday, July 17, 2016

Tonight's Sky for July 17: Jupiter Sets 2 Hours After the Sun

Tonight, Jupiter, 5th planet from the Sun and largest in the solar system, will be setting just 2 hours after the Sun, meaning that time to catch Jupiter under a truly dark sky is now virtually over and seeing the planet itself requires a relatively good Western horizon. So, if you haven't bothered to take a look at Jupiter in awhile, don't wait around much longer.

Saturday, July 16, 2016

Tonight's Sky for July 16: Comet Shoemaker-Levy 9 Hits Jupiter (1994)

On this date in 1994, telescopes all over the world were trained on the planet Jupiter, which was about to experience the first in a week-long series of impacts caused by tidally torn Comet Shoemaker-Levy 9. Going into the event, about the only things that were known was that this would be the first impact event ever to be witnessed by scientists and that no one really knew what would happen when the comet 'impacted' the gassy planet.

What did happen was spectacular.

On July 16, 1994, the first in a series of more than 20 fragments hit the planetary king, creating a large fireball and leaving a dark black area of gasses at the impact site. In time, Jupiter would come to have a virtual necklace of impact sites in its Southern Hemisphere, which also went on to have serious impact here on Earth in that, for the first time, the threat of planetary collisions from large objects shooting through the solar system was taken seriously.  

Friday, July 15, 2016

Tonight's Sky for July 15: Moon Crowds Saturn, Shadows Mars


As a bit of an encore from yesterday, which Saw the Moon, Mars, and Saturn form a triangle, the Moon will still be near Mars but will be parked extremely close to Saturn tonight. So, if you were clouded out last night, here's your second chance to catch the Moon and a pair of planets. 

Thursday, July 14, 2016

Tonight's Sky for July 14: Moon, Mars, Saturn Triangle


Want to see Mars and Saturn but have no clue where to look? Well, tonight's your lucky night as both Mars and Saturn will be very near the Moon. In fact, the three bodies will form a triangle. To see the show, simply go out and find the Moon. That done, you'll notice two bright 'stars' near Luna. These 'stars' are, in fact, the planets. Which is which? Since Mars is near its closest to Earth, it should be noticeably red in color. As for the yellow-white one, that's Saturn.



Wednesday, July 13, 2016

Tonight's Sky for July 13: 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

Monday, July 11, 2016

Tonight's Sky for July 11: First Quarter Moon Meets Spica

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.


Additionally, bright blue Spica, alpha (brightest star) Virgo, is nearby, too. 

Sunday, July 10, 2016

Tonight's Sky for July 10: Venus at Perihelion

Today,Venus is as close as it will ever get to the Sun thanks to the fact that it is at perihelion, a point in its orbit that is closest to the Sun.

What many people may not realize is the fact that Venus (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 point of an orbit farthest from the Sun, it's called aphelion. Lastly, those planetary distances taught in schools? They're the planet's average distance to the Sun.


Additionally, Venus is as fast as it will get today, too. Why is this? As a planet locked in an orbit gets farther from the Sun, the Sun's gravitational force on the planet lessens and the planet will slow down. Then, as the planet round the aphelion point and begins to move closer to the Sun, its speed will increase as the distance to the Sun decreases, culminating at maximum speed at, you guessed it, perihelion. This fact was first discovered in the early 1600s by Johannes Kepler and serves as his 2nd law of planetary motion.

Saturday, July 9, 2016

Tonight's Sky for July 9: Voyager 2 Visits Jupiter (1979)

On this date in 1979, the Voyager 2 space probe, which would become the only space probe in history to encounter all 4 gas giant planets, made its first planetary encounter when it flew past Jupiter, fifth planet from the Sun, coming within 350,000 miles of the cloud tops. While exciting in itself for professional and amateur astronomers, for the greater public, there was not an overwhelming wave of attention for this mission thanks to the fact that Voyager 1 had done the same in March.

Although observed for centuries by astronomers, the Voyagers helped scientists learn more about the planet in the 48 hours of either side of close approach than had been discovered since Galileo first turned his telescope on the planet more than 350 years beforehand at the start of the Renaissance.

In all, the Voyagers discovered volcanism on Io, a probable ocean on Europa, rings around the planet, more moons, and radiation belts, all while providing the first up close pictures of the Jovian system.
 

Friday, July 8, 2016

Tonight's Sky for July 8: Mars Sets 8 Hours After the Sun

Tonight, Mars, 4th planet from the Sun, will be setting 8 hours after the Sun, meaning that it is up pretty much all night at this point. For the record, Mars will be coming to opposition, the point in its orbit when it will be up all night, later this month.
 

Thursday, July 7, 2016

Tonight's Sky for July 7: Moon Meets Regulus

Want to see the bright star Regulus, alpha Leo, but have no idea where to look? Well, you're in luck as the Moon will be parked next to the heart of the lion low in the Western sky tonight at dusk. 

Wednesday, July 6, 2016

Tonight's Sky for July 6: Sojourner Rover Begins Exploring Mars (1997)


On this date in 1997, NASA's Pathfinder mission truly got underway as the miniature Sojourner rover drove off of its landing craft and onto t he surface of Mars, becoming the first mobile vehicle to land on another planet. Being a first of its kind mission in that it was the first rover to land on another planet and the first planetary lander to use giant airbags to cushion the landing, the world was transfixed on the mission thanks to the fact that Pathfinder/Sojourner was the first great planetary mission in the era of mass access to cable and/or satellite television as well as the Internet, which made it possible to watch live by previously unimaginable numbers of people.

As for the mission, the name was appropriate as it paved the way for the later, far more ambitious Twin Mars Exploration Rovers and (Spirit and Opportunity) of 2004 and the Mars Science Laboratory (Curiosity) of 2012. AS for this mission itself, Pathfinder/Sojourner transmitted data for 83 days (far exceeding its 30-day design life) that included roughly 2.6 billion bits of information, 16,000 images, analysis for 15 rocks, and numerous weather data measurements.

Needless to say, this was the mission that truly re-ignited the interest in planetary science that would result in a quick succession of missions culminating with the Cassini/Huygens probe, which reached Saturn in late 2004.

Unfortunately, thanks to budget cuts, NASA's ambitions of traveling to the planets and answering questions raised by the 1997-2004 series of missions will, more than likely, be restricted for the foreseeable future.

Tuesday, July 5, 2016

Tonight's Sky for July 5: Earth at Aphelion

For people living in the Northern Hemisphere, it may be hard to believe but, right now, Earth is at a point in its orbit called aphelion, which is a fancy way of saying that it is as far as it will get from the Sun. 

As for how Earth can be its hottest (at least North of the Equator) when it's at its farthest from the Sun, it has nothing to do with distance, but everything to do with geometry.

The Earth's seasons are caused by the planet's 23.5 degree tilt relative to its axis. As Earth goes around the Sun, the angle of a location relative to the incoming solar rays changes. This is the reason why the Sun apparently takes a different path through the sky (high in summer and low in winter resulting in long and short days, respectively) during the year. It is this difference in angle (and resultant day length) that causes the seasons to change.

Oh yes, Earth is roughly 95 million miles from the Sun today rather than the 93 million mile average distance taught in schools.

Monday, July 4, 2016

Tonight's Sky for July 4: 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.

Sunday, July 3, 2016

Tonight's Sky for July 3: The Dog Days Begin

It's roughly two weeks from the start of summer for us living in the Northern Hemisphere, which means that the heat is on, but it has nothing to do with a certain Dog Star. In the time of the Ancient Egypt, the people noticed that the hottest days of the year correspond to a point in time wherein Sirius, brightest star in the sky, is very close to the Sun, so close that the Egyptians thought Sirius lent its brilliance to the Sun and helped make summer, particularly the 40 days between July 3 and August 10, the hottest month of the year. 

Well, we now know that Sirius is 8.6 light years distant and plays no part in Earthly weather. Still, this is an interesting space history lesson and the explanation for a common phrase whose origin is unknown by many of the people who actually use it!


Friday, July 1, 2016

The July Sky


With the arrival of July, the Summer Solstice is still a recent memory, which means that the Sun won't be going anywhere soon. Result: those short nights are going to be sticking around, making for brief, but good times under the stars as the summer sky is, more than any other season, a cosmic picture book.

Cool Constellations
With the arrival of July, the summer sky is at its peak for viewing as all the major sights are now visible without having to stay up half the night. First of all, spring leftovers Hydra (or at least its head end),
Corvus, Cancer, Leo, and Crater will be disappearing for the year. Virgo, highlighted by bright Spica, is also getting very low in the Southwest. Also, the Big Dipper signpost is now obsolete as the last two stops in the chain are gone with only Arcturus (alpha Bootes ) and Spica (alpha Virgo ) still remaining in the sky. Back to the Dipper, it's now pointing downward come nightfall. Onto the summer sky and the cosmic picture book. First up, Corona the crown, with a little imagination, looks like its namesake, or at least a tiara. Moving over, mythological hero Hercules looks somewhat human. Continuing into the Summer Triangle, Lyra looks vaguely like an ancient lyre. Going down, Cygnus is very swan-like and Aquila, with a little imagination, looks like an eagle. The mini constellations Delphinus and Saggita? Yes, they look like their namesakes, too. Now, moving to the South, Libra, though dim, does look like an ancient string scale. Scorpius? Well, using your imagination, the profile can resemble a scorpion. Finally, Sagittarius, one look at it instantly reveals why it is nicknamed the Teapot. Also, there is the Milky Way, which arches high overhead on summer nights and serves as a good measure of how good (or bad) your sky is when it comes to light pollution. By the time the sky starts to brighten, a fall preview in the form of Pegasus, both Pisces, Cetus, Andromeda, Aries, Capricorn, Aquarius, and even Perseus is on tap, too.

Planetary Perceptions
On the planetary front, July marks a month of transition as Jupiter, which has been up for seemingly forever, is becoming a twilight object as early July offers the last opportunity to catch the planetary king under a truly dark sky. By month's end, Jupiter is strictly twilight. Additionally, for the first time in months, there are no predawn planets visible as both Mercury and Venus are in twilight, with the former making a poor twilight appearance late month and the latter making an even poorer showing at the same time. July also makes for good times when observing Mars and Saturn as both are just about due South as the sky gets dark. Unfortunately, this being summer, the planets are not all that high thanks to the flat ecliptic plane. As a final item of note, Mars is finished retrograding, which means that it will once again be converging with, and eventually passing the slower Saturn.

Tonight's Sky for July 1: 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

Thursday, June 30, 2016

Tonight's Sky for June 30: the Tunguska Event (1908)

It was on this date in 1908 that the biggest impact from a celestial body in recorded history took place over the remote Tunguska region of Siberia, Russia. 

June 30, 1908 dawned a normal morning in Siberia. Then, just past 7am, a blinding fireball as bright as the Sun came through the sky and exploded. Shock waves knocked people off their feet and windows were broken hundreds of miles away. For the next few days, nights as far away as London were as bright as day. Something extraordinary had happened, but the world would have to wait almost 20 years for scientists to pick up the case when Russian Leonid Kulik finally penetrated the vast wilderness in search of a meteorite crater and/or pieces of the space rock. He came up empty but found over 1,000 square miles of forest flattened, save a small area near the center of the region. Thanks to political instability and then WWII, the world would have to wait almost a generation for further investigation.
In the 1950s and 60s, a new generation of scientists entered the Tunguska forest in search for clues. Recalling damage patterns brought upon by nuclear weapons testing, the Russians theorized that the vast devastation was caused not by a meteor or comet impacting the Earth, but by one exploding above the Earth. Using models with match sticks on springs standing in for trees and small explosive charges for the impactor, the scientists determined that the impacting body, whatever it was, exploded about 5 miles above the Earth while coming in at an angle of around 30 degrees inclination from the horizon. The proof? Scientists were able to recreate the famous butterfly, complete with standing "trees" right above the detonation.
As for what caused the explosion in the first place, there is still lively debate in the scientific community on the asteroid vs. comet theories, with both sides having very valid arguments to support their ideas.

Perhaps the only thing that can be agreed upon is this: Tunguska serves as a stark reminder that the detection of near-Earth objects and the development of technologies to divert them from hitting the Earth should be a very pressing scientific undertaking.


Monday, June 27, 2016

Tonight's Sky for June 27: 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.     

Sunday, June 26, 2016

Tonight's Sky for June 26: The Latest Sunsets

Technical difficulties resolved, here we go again . . .
While the solstice (and shortest nights) was almost a week ago week, the latest sunsets occur now. Why is this? Short answer: celestial mechanics. As for why the Sun doesn't have its extreme rise/set dates on the day of the solstice, it all has to do with solar noon, the point in time wherein the Sun reaches its highest point in the sky, which is the basis for the timing of the solstice. Problem: the Sun doesn't always reach its highest point in the sky as seen from Earth at noon. In addition, at the time of the solstice, the lay is actually longer than 24 hours. Result: solar noon doesn't always sync up with measured noon, hence why extreme sunrises and sets do not occur on the Solstices.  

Tuesday, June 21, 2016

Tonight's Sky for June 21: Summer Solstice


Today is the longest day of the year for us living in the Northern Hemisphere. With the summer solstice comes the longest day of the year and the official start of the summer season.
So, why do we have seasons, anyway?

It's all about Earth's 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 Winter Solstice (shortest day of the year) the Northern Hemisphere is tilted up and away from the Sun. On the Summer Solstice (today), the Northern Hemisphere will be tilted down toward the Sun. On the equinoxes, the tilt is half way between the solstices. To see this effect, go out and observe the path the Sun takes through the sky for the course of day of winter).


Sunday, June 19, 2016

Tonight's Sky for June 19: 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. 

Saturday, June 18, 2016

Tonight's Sky for June 18: First American Woman in Space (1983)


On this date in 1983, Sally Ride became the first woman to enter space, which she did on the STS-7 mission flown by the space shuttle Challenger.

Sally Ride was born in 1951 in California and grew up with a fascination in 
science, which she credited her parents for encouraging. It was in 1977 as she was completing her doctorate that Ride saw an ad in the Stanford University student newspaper stating that NASA was, for the first time, going to start considering non-military applicants for its astronaut training program. Up until that time, all astronauts had been military test pilots, and male.
With this new opening to civilians, NASA was flooded with over 8,000 applications, from which it selected a mete 35 astronaut candidates, with Ride being among the lucky few. Ride's training program commenced in 1978, with certification being completed a year later.

However, Ride would have to wait 4 years to fly, when she was assigned as a mission specialist aboard the STS-7 mission on the shuttle Challenger. It was on June 23, 1983, that Ride broke the gender barrier by becoming the first American woman in space. At the time, according to Ride, the feat was not not on her mind but, only with the passage of time, did her accomplishment really begin to sink in. Ride would fly into space once more a year later before retiring from NASA in 1987.

After NASA, Ride used her immense science credentials to make a career for herself in academic as both a consultant, researcher, and professor. What could be considered the crowning achievement of Ride's non-astronaut career came in 2001 when she founded Sally Ride Science, a company that promotes science education through creation of classroom materials and programs as well as professional development for science teachers, all while continuing to serve as a consultant for various organizations.

Ride died of cancer on July 23, 2012.

Thursday, June 16, 2016

Tonight's Sky for June 16: First Woman in Space (1963)

On this date in 1963, Valentina V. Tereskova became the first woman to enter space, which she did on the Vostok 6 mission.

Valnentina Tereshkova was born on March 6, 1937 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.

Wednesday, June 15, 2016

Tonight's Sky for June 15: Be Alert for Aurora

Earth is entering a high-speed  stream of solar wind today, which is already creating G1 class geomagnetic storms. Experts at NOAA are advising high latitude skywatchers to be alert for aurora, commonly known as the Northern Lights, to keep an eye on the sky tonight. 

Tuesday, June 14, 2016

Tonight's Sky for June 14: The Earliest Sunrises

While the solstice (and shortest nights) will not occur for about another week, the earliest sunrises occur now. Why is this? Short answer: celestial mechanics. As for why the Sun doesn't have its extreme rise/set dates on the day of the solstice, it all has to do with solar noon, the point in time wherein the Sun reaches its highest point in the sky, which is the basis for the timing of the solstice. Problem: the Sun doesn't always reach its highest point in the sky as seen from Earth at noon. In contrast, the Sun is at its peak elevation about a week before the solstice in summer, which means that, solar noon being about 8 minutes before Earth noon, that also means that the sunrise occurs about 8 minutes earlier, too.  

Friday, June 10, 2016

Tonight's Sky for June 9: Johnann G. Gallee is Born (1812)

On this date in 1812, Johann G Gallee, the man who discovered Neptune, was born in Radis, Germany. At an early age, Gallee excelled in academics and eventually became a teacher before becoming assistant at the Berlin Observatory in 1835. Gallee's supervisor there was none other than Johann Franz Encke of comet fame. Using a 9-inch refractor, Gallee proceeded to discover 3 comets and an inner, dark ring surrounding Saturn.


In 1846, using calculations from French astronomer Urbain le Varrier, Gallee discovered the planet Neptune, whose locations was theorized from orbital oddities discovered in the path Uranus took around the Sun, which suggested an eighth, more distant planet.

Following his discovery of Neptune, Gallee would work as both a professor and observatory director. In all, Gallee published over 200 scientific works in a long career. Gallee died in 1910 at the age of 98.

Thursday, June 9, 2016

Tonight's Sky for June 8: Christian Huygens Dies (1695)

On this date in 1695, Christian Huygens, the man who discovered Saturn's largest moon, Titan, died at the age of 66. A leading scientist of his time, Huygens made scientific contributions in the areas of what. In terms of astronomy, Huygens invented a 50 power refracting telescope, which he then used to discover the first moon of Saturn, Titan, and complete the most detailed examination of Saturn's rings up to that time, becoming the first man to suggest that Saturn was, in fact, surrounded by a ring at all. In addition, Huygens is noted for his making of the first drawing of the Orion Nebula and for his discovery of several nebulae and binary stars.

Monday, June 6, 2016

Tonight's Sky for June 6: Venus at Superior Conjunction

Today, the planet Venus has reached superior conjunction. What does that mean? In layman's terms, Venus will be directly opposite the Sun as seen from Earth in a Venus, Sun, Earth alignment. End result: the planet will be at its worst point for viewing. This stands in contrast to an inferior conjunction, during which Venus would come directly between the Sun and Earth. 

Sunday, June 5, 2016

Tonight's Sky for June 5: Mercury at its Best

Want to join a small club of people who have seen the planet Mercury? Well, here's your chance as the first planet from the Sun will be making its best appearance of the fall this morning.

Of all the Classical Planets (those known to the Ancient Greeks and Romans), Mercury is by far the hardest to spot because, as seen from Earth, it never gets very far away from the Sun. As a result, Mercury is often obscured from view by the Sun's glare.

As of today, Mercury has reached a point in its orbit called greatest elongation, which is a fancy way of saying that, as seen from Earth, Mercury is as far from the Sun as it will get on this orbit and making its best morning appearance of the year. How good is it? So good that Mercury sets about an hour and a half after the Sun! So good that, even 30 minutes after sunset, Mercury is still about 10 degrees up from the horizon. To simulate, hold your fist vertically at arm's length. While that may not seem overly high, for elusive Mercury, that's quite good.


So, take a moment or two, go out just before dawn, and try to spot Mercury. If you are successful in spotting the speedy planet, you are accomplishing something that the great astronomer Nicolaus Copernicus (who rediscovered the idea of a sun-centered solar system) supposedly never did.

Saturday, June 4, 2016

Tonight's Sky for June 4: 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.

Friday, June 3, 2016

Tonight's Sky for June 3: Old Moon Meets Mercury


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. To aid matters, Mercury is in the area, too.

Thursday, June 2, 2016

Tonight's Sky for June 2: Saturn at Opposition

Tonight, the planet Saturn, 6th from the Sun, will be at opposition. What does that mean? In short, if viewed from above, the Sun, Earth, and Saturn would be in a straight line in that order, with Saturn exactly opposite the Sun in the sky as seen from Earth. End result: Saturn rises as the Sun sets and Saturn sets as the Sun rises, meaning that Saturn is up all night. Oh yes, opposition technically takes place tomorrow but tomorrow brings a very worthy sight that deserves its own article.

Wednesday, June 1, 2016

Tonight's Sky for June 1: Short Nights

Today brings the month of June, and with it, the shortest nights of the year as the Solstice arrives on the 20th, signaling the shortest night of the year. However, while June nights may be short, they're long on sights by reading the below article, so try and get out for a look. 

The June Sky


The arrival of June also heralds the first day of summer and thus, the Summer Solstice, the longest day of the year. Since the length of day/night varies with latitude (the more North you go, the more extreme the lighting), not all people will be having equal length nights on the longest day of the year. On the other hand, one thing is common for all Northern Hemisphere observers: the nights are sort, especially when considering that it the approximately 1 ½ hours after sunset and before sunrise aren't truly dark. Now the good news: the summer sky is a cosmic picture book.

Cool Constellations
By the time June arrives, some of the Spring constellations are already taking their annual dives out of view. Among these are Hydra, Cancer, and, to a lesser extent, Leo. By the arrival of June, the Big Dipper signpost is starting to become obsolete. As the Dipper begins its annual dive, on the other end of the arc,Corvus and Crater are already disappearing but Bootes and Virgo are coming into their best placements of the year. By the time July comes, you'll only be able to speed on to Spica under a truly dark sky. Besides the already mentioned herdsman and virgin, and crown, Hercules, the Summer Triangle (made up of constellations Lyra, Cygnus, and Aquila), Ophiuchus, and Serpens are all flying high at this time of year, too. For those who like to stay up later, Libra and Scorpius are also on the rise, as is deep sky treasure trove Sagittarius along with the ghostly arch across the sky that is the Milky Way. By the time the sky starts to brighten around 4:30am (sunrise is before 5:55 in mid month), a fall preview in the form of Pegasus, Andromeda, Aries, Capricorn, Aquarius, and even Pisces Australis is on tap, too.

Planetary Perceptions

On the planetary front, June marks a transition in that, for the first time in months, the majority of the planets are well-placed by the time the sky becomes dark which, this time of year, is rather late, but at least seeing the majority of planets won't involve staying up well past the arrival of true night. By the time it gets dark, Jupiter is in the Southwest and Mars, closely followed by Saturn, which comes to opposition on the 3rd, are in the Southeast. The good news is that three of the best planets to view with a telescope are near opposition this month, the bad news is that, thanks to the flattening ecliptic plane, their placement is less than ideal because viewing them requires looking through a lot of atmosphere which, in a telescope, can result in unsteady seeing at high power. Hint: dusk often offers a window of steady air good for planet viewing. Additionally, Mars's racing away from Saturn will slow until,come month's end, it becomes stationary as its retrograding period ends. Moving into the morning, Mercury will make a good for this time of year appearance mid-month. Venus? It's lost in the Sun's glare all of June but will be reappearing, albeit barely, come next month.  

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.