Wednesday, December 31, 2014

Tonight's Sky for December 31: Ring in the New Year With Sirius

Tonight marks the last day of the year and a rare event wherein just about everyone stays up until midnight. While a big ball dropping in New York City is a widely-watched way to ring in the new year, thanks to pure chance, there's a celestial sight that works well in doing the same job. 

After the ball drops, go out and spot Sirius. Doing this is easy as Sirius is an unmistakable blue color, the brightest star in the sky, and is just about due South about half way up in the sky at midnight.


Tuesday, December 30, 2014

Tonight's Sky for December 30: Can You See Mercury?


You may have noticed that there was little mention of
Mercury, first planet from the Sun all month. Why? Well, it simply hasn't been visible, but that's changing now as the little planet is starting to pop over the Western horizon immediately after sunset. How low will you need to look? About three degrees up from the horizon. To simulate, a little finger held at arm's length spans about a degree of sky. Needless to say, binoculars are a must!

Monday, December 29, 2014

Tonight's Sky for December 29: The Latest Sunrises


While the solstice (and shortest nights) was last week, the latest 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 latest sunrise occurs about 8 minutes earlier, too, thus resulting in the Sun's lowest point at Earth noon being about a week after the solstice.

Sunday, December 28, 2014

Tonight's Sky for December 28: 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..

Saturday, December 27, 2014

Tonight's Sky for December 27: Saturn Rises 3 Hours Ahead of the Sun


Anyone wanting to view Saturn of late has not had much luck thanks to the ringed wonder's close proximity to the Sun. However, things are getting better. This morning, Saturn will be rising three hours before the Sun. To see Saturn this morning, go out just before sunrise and look low in the Southeast. That bright 'star' is, in fact, the planet.

Friday, December 26, 2014

Tonight's Sky for December 26:: Mary Somerville is Born (1780)


It was on t his date in 1780 that Mary Somerville, one of the first women to become famous in the field of astronomy, was born.

Somerville's tale is one of struggle against adversity. At the time, girls were not only often denied access to an education, but were often discouraged from seeking one. Mary's situation was no different and her parents even blamed her quest for knowledge for the death of her own sister! While giving up on formal education and taking the societal path of a well-connected lady (her father was a doctor), Mary continued to study in secret and, with the inheritance she got upon the death of her husband, she was free to pursue intellectual interests, with the support of her second husband, eventually becoming known as both a writer and translator.


She was also one of the first women to be inducted into the Royal Astronomical Society, which she achieved in 1835, the same year that Caroline Herschel, William Herschel's sister and assistant, received the same honor. In 1868, Somerville was awarded the Victoria Cross of the Royal Geographical Society.

Somerville died in 1987, aged 91.

Thursday, December 25, 2014

Tonight's Sky for December 25: Issac Newton Born (1642)


It was on this date in 1642 that Issac Newton, one of the greatest men of science, was born.

His intelligence recognized at an early age, Newton was sent to Cambridge fr a college education, which was a rarity for the non-elite at the time. It is here that one of histories greatest ironies took place. In 1665, the Plague came to London and virtually shut down the city, Cambridge included. With classes canceled, Newton returned to his home and proceeded to invent calculus, discover his 3 laws of motion, and mathematically express the law of universal gravitation. The latter two of these basically solved the 'whys' of planetary motion, which had puzzled everyone to this point. The irony in all of this: if Newton had been occupied with his intended course of study, he would never of had the time to think about such things.

Another irony: Newton's greatest achievements were already accomplished by the time he was 30. For the remaining 54 years of his life, Newton would continue working in the sciences, publishing, and even be appointed head of the Royal Mint. Newton was knighted in 1705.

Tuesday, December 23, 2014

Tonight's Sky for December 23: Easy Thin Moon


While last night's Young Moon was a challenge, things get a lot easier tonight as one can see a still very thin crescent Moon without having to make an effort to do so. Simply go out after sunset and look low in the Southwest. 

Monday, December 22, 2014

Tonight's Sky for December 22: Young Moon Meets Venus

Tonight will offer a beautiful, though very challenging sight right after sunset as the Young Moon and Venus will be very close to each other. How low will you need to look? About three degrees up from the horizon. To simulate, a little finger held at arm's length spans about a degree of sky. Needless to say, scouting out a location ahead of time is a very good idea.

Location found, go out right after sunset and start scanning the horizon with binoculars. In modest powers (7-10x), one should be able to scrape the horizon at the bottom of the field of view and sweep up the Moon and Venus towards the middle or top. If you don't see the pair right away, don't worry as they will often seemingly pop out of nowhere and into visibility.

However, if you're still looking 30 minutes after sunset, you've missed the show.

Sunday, December 21, 2014

Tonight's Sky for December 21: Winter Solstice and New Moon

Technical problems resolved again . . . hopefully for good . . . back in business!

Today marks two major celestial events with one being a once a year event and the other a once a month (usually) happening.
Today marks the Winter Solstice for us living in the Northern Hemisphere. With the Winter Solstice comes the shortest day of the year and the official start of the winter 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, the Northern Hemisphere is tilted up and away from the Sun. On the Summer Solstice (in June), the Northern Hemisphere will be tilted down toward the Sun. On the equinoxes, the tilt is half way between the solstices.

In practical terms, the Sun has its most Northerly rise/set with highest arc through the sky in summer and the most Southerly rise/set with lowest arc in winter.


Second
, 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.

Tuesday, December 16, 2014

Tonight's Sky for December 16: Edward Emerson Barnard Born (1857)


It was on this date in 1857 that the American astronomer Edward Emerson Barnard was born in Nashville, Tennessee.

Barnard gained fame as an amateur astronomer. As a hobbyist, Barnard discovered 5 comets after Hulbert Harrington Warner offered a prize of $200 per comet discovery. With this money, Barnard built a house for himself and his wife. This feat propelling him to fame, a group of Nashville amateurs pooled enough money to get Barnard into Vanderbilt University. Barnard never graduated but received the only honorary degree Vanderbilt ever awarded.

From there, Barnard moved onto working at observatories, where he discovered Iapetus and Amalthea, the fifth Moon of Jupiter and the last to be discovered visually. Working at the Yerkes Observatory, Barnard used the great 40-inch refractor and became a pioneer astrophotographer. Additionally, he discovered Barnard's Star, the second closest to Earth.  

Monday, December 15, 2014

Tonight's Sky for December 15: Capella Near Zenith at Midnight

Technical problems are finally resolved so it's back to business!
Don't have a watch? Well, no problem, at least at midnight as Capella, alpha Auriga, is just about overhead midnight. To see it, just go out and look straight up. See that bright star? That's Capella.

Monday, December 1, 2014

Tonight's Sky for December 1: Moon Meets Uranus

New to astronomy? Want to see Uranus but don't know where to look? Well, it's your lucky night as the Moon will be right next to the Uranus. 

To see Uranus, just go out before sunrise and look up as the Moon is, of course, impossible to miss. As for Uranus, grab a pair of binoculars and it's that greenish 'star' right next to Luna. The way to tell that Uranus is a planet (besides its color)? . In a telescope, Uranus is obviously not a star as a planetary disc is very evident at high powers. As for what this means, look at Uranus and notice its clear-cut edges. Then swing to a star and notice its diffuse edges.

The December Sky

With new month of December upon us, people in the Northern Hemisphere will be treated to the longest nights of the year as the Winter Solstice arrives on the 22nd of this month. However, when it comes to changes in days' lengths, December is pretty much a story of steady 15-ish hour nights, give or take a few minutes at most, for much of the United States.. So, with all of this night, what's there to see?

Cool Constellations
By nightfall in December the fall constellations are all very well-placed for early (emphasis, early!) evening viewing. First up, we will have one last chance to see the summer constellations, provided you have a good West horizon. Hurry, though, they'll quickly disappear (at least in the West) for good by month's end. Moving onto more mainstream celestial landmarks for this time of year, the Great Square of Pegasus is high overhead and the Big Dipper is scraping the Northern horizon. Starting at the Great Square, look at the double string of stars coming of third base as they constitute Andromeda. High in the Northeast is ‘W’-shaped Cassiopeia, house-like Cepheus, and a twisted ‘V’ of stars, the mythological hero Perseus. Below Perseus is the bright Capella, alpha Auriga, and below his feet, the cloudy patch that is the Pleiades. In the early evening, the South, save bright Fomalhaut, is a dark void populated by the dim constellations of Capricorn, Aquarius, Pisces, and Cetus. If you stay up a little later as in a couple of hours after dark (which is no longer a chore/something you later regret doing at this time of year), you'll see all the winter favorite like unmistakable Orion in the South, which also serves as a winter signpost to the stars. From Orion, follow a line from his belt down to blazing blue Sirius, alpha Canis Major. Following that line up will bring one to Aldebaran, alpha Taurus the bull. Imagining a line starting at bright blue Rigel (Orion's left foot) through red Betelgeuse (Orion's right shoulder) will bring you to Castor and Pollux, alpha and beta Gemini. Other winter favorites to look for include Canis Minor, Cancer, and even Leo if you wait into the night a little longer. Early birds? Well, getting up just before the Sun will bring a spring preview in the form of Virgo, Bootes, Corona, Hercules, Corvus, and even Vega just ahead of the rising Sun.

Planetary Perceptions
Though still not exactly a good month for planet viewing, December is a bit of an improvement over November. As was the case last month, Mars hangs low in the Southwest sky virtually all month, setting roughly 3 hours after the Sun. Additionally, Venus re-emerges in the dusk sky this month, climbing higher as the month continues. Like Venus, Mercury drops from morning visibility to evening, re-emerging from the Sun's glare as a dusk object at month's end. Moving into the night, Jupiter is visible for most of the night as it heads toward opposition. As for Saturn, the ringed wonder continues its reemergence from the Sun's glare in the morning. By month's end, Saturn rises just over 3 hours ahead of the Sun.

Fun Thing to Do
With the longest nights of the year upon us, this is the time when you can see the same star twice in one night, as is on the set in the evening and on the rise in the morning. Despite this being the first month of winter, the summer stars are still visible in the sky at dusk. The stars of the Summer Triangle make perfect targets because of their brightness. As for what to do, simply go out and observe the stars of the Triangle (Vega is best as it is the brightest and will be first to rise in the morning). That done, either go to bed or stay up and enjoy the night until just before sunrise. At that point, go out and look in the Northeast for your chosen star's return to the sky. How many people can say they saw the same star twice in one night that way?