Sunday, January 31, 2016

Tonight's Sky for January 31: Third Quarter Moon #2


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.'

Oh yes, this is the second Third Quarter Moon of the month. 

Saturday, January 30, 2016

Tonight's Sky for January 30: 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

Friday, January 29, 2016

Tonight's Sky for January 29: Venus Rises 2 Hours 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 impossible to see the brilliant planet under a truly dark sky anymore. As the weeks progress, Venus will only get lower and lower until it reaches solar conjunction (and thus invisibility), which is set for June.

Thursday, January 28, 2016

Tonight's Sky for January 28: The Challenger Disaster (1986)


It was on this date in 1986 that the space shuttle Challenger exploded, on live television.


As 1986 began, NASA was on a tear with its new space shuttle fleet, launching 25 missions in the program's first 5 years while utilizing an incomplete fleet (Columbia was first in 1981, Challenger next in April '83, Discovery in August '84, and Atlantis in October '85). By this time, spaceflight had almost become routine as NASA increasingly cut turnaround times and launched in colder weather. On January 12, 1986, Columbia completed the shuttle program's 24th official mission.

A few weeks later, on January 28, millions of eyes in both the United States and across the world were on shuttle Challenger because of the inclusion of teacher in space contest winner Christa McAuliffe. As the shuttle rose from the launchpad, it seemed another routine launch until, unnoticed by many at the time, a burst of flame erupted out of Challenger's right solid booster because of a failed o-ring. The booster came loose, impacted the rest of the vehicle, and ignited the escaped gasses. The orbiter itself fell from a height of over 60,000 feet into the Atlantic Ocean, killing all 7 astronauts aboard.

For a nation where anything seemed possible, the loss of Challenger was devastating, with the shuttles being grounded until 1988 until the investigation of the disaster was complete. The irony: engineers had objected to the launch before it took place on account of the cold (it was only 26 Fahrenheit), warning that the rubber o-rings could shrink and/or harden and fail, which is exactly what happened. 

Wednesday, January 27, 2016

Tonight's Sky for January 27: The Apollo 1 Disaster (1967)


It was on this date in 1967 that astronauts Gus Grissom, Ed White, and Roger Chaffe were killed in a test of the Apollo space capsule in the lead-up to what would have been Apollo 1.

In retrospect, it's now clear that NASA was proceeding too fast into unknown territory. With just under 3 years left to fulfill President Kennedy's pledge to go to the Moon by decade's end, there was immense pressure on NASA to get an Apollo mission off the ground. Additionally, the Apollo space capsule was by far the most complicated ever constructed to that point. The result: corners were cut, many last-minute changes were made to the craft, and the crew was very nervous about the mission. Grissom, one of the Mercury 7, was especially vocal in his concerns.

During a routine plug-out test, where the ability of the craft to run off its own power was checked, a fire broke out at a point that was never determined. The fire, pure oxygen atmosphere, flammable materials inside the cabin, and inward-opening escape hatch held in place by a pressurized cabin all combined to doom the astronauts. The following investigation and changes to the craft design it demanded set back the Apollo program by over a year.

Ironically, even with this 1-year delay (which was far longer than the delay that would have been created by fixing the problems before the first test), we still fulfilled Kennedy's pledge. 

Tuesday, January 26, 2016

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

The Sun's atmosphere has opened up in a coronal hole, which is now spewing a blast of the solar wind into space. This burst of solar wind is expected to impact Earth in tonight into tomorrow morning. In analyzing the incoming data, NOAA is forecasting up to a 40% chance for geomagnetic activity today and tomorrow for North-dwelling sky watchers. Bottom line: if you live in Northerly latitudes, keep an eye out for the Northern Lights tonight and possibly tomorrow night, too.  

Monday, January 25, 2016

Tonight's Sky for January 25: Moon Meets Regulus


Want to see Regulus, alpha (brightest) star of Leo the lion but don't know where to look? Well, no problem because, tonight, the
Moon will be parked right next to Regulus. To see the show, head out and look East to find the Moon. That bright star next to it? That's Regulus.

Sunday, January 24, 2016

Tonight's Sky for January 24: Monster Blizzard From Space


Well, it's not exactly a sight in the sky, rather a sight that will prevent many people from seeing the sky. What is it? It's the monster blizzard of 2016 snapped from space. 

Saturday, January 23, 2016

Tonight's Sky for January 23: 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. 

Friday, January 22, 2016

Tonight's Sky for January 22: Can You See 5 Planets at Once?

Mercury is on the rise in the predawn Eastern sky and should now be relatively easy to spot now, which also means that you should be able to see all 5 classical planets at the same time. While none of them are spectacularly close together, being able to see all 5 of the naked eye planets at once is a bit of a rarity. To see the show, head out about 30 minutes before sunrise and look in the Southwest to spot Jupiter. Moving to the East, you'll next come to reddish Mars, Saturn, brilliant Venus, and finally ground-hugging Mercury. Clouded out today? No problem, this show will continue for a couple of weeks. 

Thursday, January 21, 2016

Tonight's Sky for January 21: Cosmic Soccer, Pollux?



Tonight, there will be a bit of cosmic soccer, of sorts, as the Moon will be parked right next to the cosmic twins, Gemini, and more specifically, next to the foot of Pollux, the lower of the twins as seen when the constellation is just starting to rise in the East. As a second activity, if you have a telescope handy, turn it on Castor, the other twin as it is a binary (multiple) star system and see how many of the companion stars you can spot. For the record, Castor is a 6-star system. 

Tuesday, January 19, 2016

Tonight's Sky for January 19: Moon Meets the Bull


Tonight, the Moon will be in a very unique place: right between the horns of a cosmic bull. Tonight, the Moon will move directly into the Zodiac constellation of Taurus the bull, more specifically, between its horns.

To see the sight, go out and look East in the predawn sky before the sky starts to brighten. The Moon, of course, will be impossible to miss. Moon found, look for a sideways 'V' of stars, the Hyades star cluster, which represent the base of the bull's horns. Extending the lines of the 'V' out, you will run into a pair of stars of roughly 2nd magnitude (though on opposite ends of the scale) that signal the end of the horns.


Cosmic picture realized, there's the Moon, smack in the middle. 

Monday, January 18, 2016

Tonight's Sky for January 18: Be Alert for Aurora

The Sun let off a coronal mass ejection (CME) on January 15 and that CME is expected to impact Earth in the coming hours. While the hit will not be direct, NOAA is still saying that there is up to a 45% chance for geomagnetic activity today and tomorrow for North-dwelling sky watchers. Bottom line: if you live in Northerly latitudes, keep an eye out for the Northern Lights tonight and possibly tomorrow night, too.  

Sunday, January 17, 2016

Tonight's Sky for January 17: Comet Catalina Meets the Big Dipper

Slowly-brightening Comet Catalina, estimated to be roughly at +6 magnitude, just inside the naked eye range for most people from a dark sky, will be a bit easier t o spot in the coming days thanks to the fact that it is very near the Big Dipper. As a visual, Spaceweather has a cool overlay map here.

Saturday, January 16, 2016

Tonight's Sky for January 16: 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. 

Friday, January 15, 2016

Tonight's Sky for January 15: Last Chance for Aurora


The unexpected aurora event of the past 3 days will continue tonight, albeit at a subsiding strength. Tonight, NOAA is advising North-dwelling skywatchers that there is approximately a 20% chance of geomagnetic activity tonight.

Thursday, January 14, 2016

Tonight's Sky for January 14: Edmund Halley Dies (1742)

It was on this date in 1742 that English astronomer Edmund Halley, best known for predicting the return of the comet that now bears his name, died at age 85.

Born on November 8, 1656, Halley had an interest in mathematics and astronomy at an early age and published his first scientific papers while still an undergraduate student. Appointed assistant to the Astronomer Royal at the Greenwich Observatory in 1675, Halley traveled to the St. Helena and was so instrumental in mapping the Southern sky that he became known as 'the Southern Tycho' in tribute to the great Danish astronomer Tycho Brahe, whose work marked the pinnacle of pre-telescopic astronomy. However, it is for a comet that Halley would be remembered.


Looking through astronomical records, Halley noticed that there seemed to be a pattern to sightings of a Great Comet, namely that one was seen every 76 years. Using the past to predict the future, Halley theorized that these several comets were, in fact, a single comet returning every 76 years. Halley then boldly predicted that a great comet would be seen again in 1758. Unfortunately, Halley before he was vindicated.   

Wednesday, January 13, 2016

Tonight's Sky for January 13: Continued Chances for Aurora

In a continuation from yesterday, NOAA is advising high-latitude skywatchers to continue to be alert for aurora tonight, adding that odds of displays are as good as 50%.

Tuesday, January 12, 2016

Tonight's Sky for January 12: Be Alert for Aurora

NOAA is advising people in upper latitudes to be alert for aurora tonight as t he Earth is now in the midst of a co-rotating interaction region (CIR), which is a fancy way of saying that the Earth is transitioning from a fast to slow moving solar wind stream. There were expectations that Earth would enter this region today but aurora were reported last night, meaning that the chances are rather good that the show will continue tonight as well. 

Monday, January 11, 2016

Tonight's Sky for January 11: Mars Rises 6 Hours Ahead of the Sun

This morning, Mars, fourth 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 go out and take a look at it?

Friday, January 8, 2016

Tonight's Sky for January 8: 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. 

Wednesday, January 6, 2016

Tonight's Sky for January 6-9: Planets and the Moon in the Morning

This morning, the Moon will join Saturn and Venus low in the Southeastern predawn sky. To see the show, simply head out as the sky starts to brighten and look Southeast to spot the Moon and two nearby bright 'stars,' which are, in fact, Saturn (the dimmer one) and Venus (the brighter one). All three bodies will be within 10 angular degrees (a fist held at arm's length) of each other. Clouded out this morning? No worries, an encore is coming tomorrow, with the moon moving below the planets.

If that weren't enough, come the mornings of the 8th and 9th, Venus and Saturn will be within a half of a degree of each other. To put that in perspective, hold your little finger at arm's length to simulate a degree. The planets' separation these two mornings will be about a third of a degree.  

Tuesday, January 5, 2016

Tonight's Sky for January 5: Venus and Saturn Within 5 Degrees

They've been converging awhile now, and now Venus and Saturn are within 5 angular degrees of each other in the predawn sky. To simulate, hold 3 fingers against each other at arm's length. However, things will be getting better. Keep an eye on this pair as they're moving toward each other fast and will come to within half a degree of each other come the morning of the 8th and 9th. If that weren't enough, the Moon will be parked just about directly between Venus and Mars, which appears as a reddish star above and right of the Moon.

Monday, January 4, 2016

Tonight's Sky for January 4: Earth at Perihelion

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 perihelion, which is a fancy way of saying that it is as close as it will get to the Sun.

As for how Earth can be its coldest (at least North of the Equator) when it's at its closest to 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 91 million miles from the Sun today rather than the 93 million mile average distance taught in schools.

Sunday, January 3, 2016

Tonight's Sky for January 3: Quadrantid Meteor Shower Peaks


Tonight/tomorrow morning will mark the peak of the Quadrantid Meteor shower for 2016, thus marking the climax for the week-long event. Every December into January, Earth passes through the stretch of space junk shed by minor planet 2003EH, reaching the deepest concentration of debris tonight. According to some estimates, under ideal conditions (dark country skies), one can expect to see 100 meteors per hour. The reason the meteors are called Quadrantids is because the meteors seem to radiate from the now-defunct constellation Quadrans Muralis, which overlapped with Ursa Major and Bootes. The specific radiant location is right behind the Big Dipper's handle. The best time to view the shower is in the predawn hours as the radiant is at its highest then.

Don't want to stay up that late? Don't worry as the radiant is circumpolar/near enough so for us in the United States to have a chance to see the meteors all night, albeit that they will probably be low in a light dome. 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.
Unfortunately, this year's Quadramntid peak coincides with the Full Moon. The good news: even the Moon won't be able to drown-out the brightest meteors with all its light.


Note: unlike many meteor showers that have long peaks lasting all night, the Quadrantids have a sharp peak, which can often result in only a few meteors all night, a sudden outburst, and then very few thereafter.

Saturday, January 2, 2016

Tonight's Sky for January 2: The Earliest Sunsets, Third Quarter Moon

While the shortest day of the year, the Winter Solstice, is about two weeks in the past, the earliest sunsets of the year will occur this week for us here on Earth, regardless of where you live, despite the fact that sunset times vary depending on latitude.
Right now, the Sun is setting at its earliest time and will continue to set at the same time for the next few days before gradually creeping later into the evening.
So, with the Sun down so early (and resulting in the longest nights of the year), why not head out and view the stars? After all, the December sky has a lot to offer. After all, at what point of the year can you see a year's worth of stars in a given night? Don't believe me? Head out just after dark tonight and look up for the Summer Triangle. Then, just before sunrise, go out again and look for a bright blue star in the Northeast just above the horizon. That's Vega, the same Summer Triangle Star you saw the previous night.


Additionally, 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.   

Friday, January 1, 2016

The January Sky

With new year and new month of January upon us, people in the Northern Hemisphere will still be treated to some of the longest nights of the year as, even after the solstice, the Sun won't be moving North very much anytime soon, meaning that changes in the length of t he night, while present, are very hard to notice So, with all of this night, what's there to see?

Cool Constellations
By nightfall in January 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 Triangle, provided you have a good West horizon. Hurry, though, it will 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 rapidly sinking in the West and the Big Dipper is starting to climb in the Northeast. Starting at the Great Square, look at the double string of stars coming of third base as they constitute Andromeda. High in the North 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 Southwest is a dark void populated by the dim constellations of Capricorn, Aquarius, Pisces, and Cetus, all 4 of which are to soon disappear. If you stay up a little later as in a couple of hours after nightfall (which is no chore 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
On the planet front, if you want to see any of our solar system neighbors, you had better be an early bird because 4 of the 5 naked eye planets make their appearances in the predawn morning sky at the start of the month and, by month's end, seeing any planets will require staying up until around midnight as Mercury will drop out of evening visibility by the end of the first week of the new month. Moving into the night, Jupiter and Mars both continue their climbs in the predawn Eastern sky while Venus continues dropping, which is what it began to do in October and then, noticeably in November. By month's end, Venus will be rising just ahead of the Sun in the predawn sky Also of note, the Moon will be making several near passes of these bodies in the early part of the month. As for Saturn, which disappeared into the dusk glow back in mid November, it will be visible low in the predawn Southeastern sky and actually relatively easy to spot by month's end. As for Mercury, it will disappear from the evening sky about a week into January but will reemerge as a morning object just ahead of the Sun by months end very near to blazing Venus.

Seeing Double
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?



Tonight's Sky for January 1: Ceres Discovered (1801)
It was on this date in 1801 that the largest asteroid, Ceres, became the first asteroid to be discovered.

At the time, there was a hypothesis known as the Titus-Bode Law (since discredited), which states that distances of planets from their parent star and relative to each other can be determined by mathematical formula. With the 5 classical planets, the pattern seemed to hold true save a gap between Mars and Jupiter. When Uranus was discovered, by pure chance, it fit the pattern, increasing belief in the Titus-Bode Law and causing a renewed interest in finding the missing planet that was hypothesized to be located between Mars and Jupiter.

It was on New Year's Day 1801 that Giuseppe Piazzi discovered this 'planet,' which he named Ceres after the Roman goddess of agriculture. The largest body in the asteroid belt, Ceres contains about a third of the Asteroid Belt's mass and its diameter is about a third that of the Moon.

Initially classified as a planet, Ceres retained that status for about 50 years. The turning point: the discovery of more small bodies in the same region, which eventually caused astronomers to realize that a whole new class of objects, asteroids (meaning 'star-like') existed in this region. In time, Ceres was reclassified as an asteroid and became officially known as 1 Ceres for the fact that it was the first asteroid ever discovered. Come 2006 and the whole Pluto reclassification/definition of 'planet' controversy, Ceres was reclassified also, getting promoted to dwarf planet. To date, Ceres is the only dwarf planet in the inner solar system.