Lyre Solo (or Solo Lyre)

.....The constellation of Lyra is small, but it holds one corner of the Summer Triangle, and the fifth brightest star in the sky - the second brightest star in the northern sky.  Lyra contains the star Vega noteworthy because this constellation, unlike some others like Scorpius, is quite high in the sky in the northern hemisphere, passing directly overhead of the southern United States.  (Spookily, Vega passes almost directly overhead of Washington D.C..) 

.....While this is something that I have done for the last few constellations, I have a more well-defined standard format for how constellations are presented.  The first map shows the sky, centered on the constellation in question, with a radius of thirty degrees.  For all but the largest constellations (and Lyra is kind of small), this will show a number of bordering constellations.  This gives us a standard starting point, and helps us find the constellation in the sky.  (In the case of Lyra, this helps us find other constellations as Vega is pretty hard to miss.)

.....Zooming in on Lyra (this map has a radius of eight degrees, we see Lyra as it is usually portrayed, a triangle of stars sharing a corner with a parallelogram.

.....Looking up on a summer night, Lyra seems quite and serene.  Less than a dozen stars, one bright, but otherwise quite.  Actually, Lyra has some notable weirdness to its stars.  Vega is larger and more luminous than the Sun, but its brightness in the sky is due to its closeness.  Vega is only a little more than 25 light years away, so the light that you can see from Vega tonight left in late April of 1986.  Being close, Vega is relatively easy to study, and astronomers have fond a massive disk of gas and dust around Vega, with irregularities that might indicate the presence of planets.  Weirder than this is the other star only in the "triangle" of Lyra, designated Epsilon Lyrae.  Through binoculars (and on the second map), this star is revealed as a pair of stars close together in the sky.  This is no coincidence; those are actually orbiting a common center of mass - but it get stranger.  Looking through a telescope with high magnification on a clear, steady night, each of these stars is revealed as a double star in their own right, so this is also called the Double-Double, four stars orbiting in pairs that orbit each other.

.....Even weirder is Sheliak, or Beta Lyrae.  Sheliak is 882 light years away, so for the light reaching us (from 1129, the year of the Council of Troyes franchising the Knights Templar - let's see what Dan Brown does with that) to still make Sheliak the second brightest star in constellation must be something outstanding indeed!  Sheliak is also a double star; nothing strange in this, most stars orbit in pairs (or more).  In Beta Lyrae's case, the two stars are so close together that the gravity of each star distorts the other, and material is pulled off of one towards the other.  These stars are orbiting so quickly that as the stream of gas moves toward the hotter star, it misses the star, building up into a disk.  Even this disk overflows, with material escaping into space from the poles, and leaking out from the opposite side of the accretion disk

.....Because Lyra is a fairly tiny constellation, I have included two telescope objects on this map as well.  This kind of skips ahead in my plans, since I intend to discuss these objects on my next tour of the constellations, but if you have even the smallest of telescopes, the object M57, aka the Ring Nebula, is straightforward to find between Sulafat and Sheliak.  (When I was in seventh and eighth grade, my backyard telescope had a lens actually slightly smaller than the human eye, and a tripod with legs six inches long that I would need to balance on the posts of a chain-link fence.  I could find Jupiter, Saturn, the Orion Nebula, the Andromeda Galaxy ... and the Ring.  The other deep-sky object is M56, a globular cluster that is one of literally dozens of globular clusters that can be seen in the summer sky.

.....As a last point, I have previously discussed how the north star can be hard to find because the constellation it is in is so faint.  Also, there are a number of people who (if pressed) will claim that the North Star is the brightest star in the sky.  (There is at least one who simply tongue-in-cheek defines the North Star this way be fiat.  Her car has GPS, so navigating by the stars is not a daily requirement.)  The North Star is not the brightest, but due to the Earth's long, slow 26,000 year wobble on its axis, if you wait about twelve thousand years, you (or your head in a jar) can see Vega as the star closest to the pole.

The August Sky

.....August is one of the best observing months of the year.  The nights are starting to get a bit longer (still cursed by Daylight Savings Time), and the Summer Milky Way, including the center of the galaxy, moves across the center of the sky from Perseus in the northeast, through Cassiopeia, Cepheus, Cygnus, Aquila, Sagittarius and Scorpius.  While I have not yet discussed many of the constellations with the Milky Way, just wandering through this section of the Milky Way with binoculars is wonderfully rewarding.

.....As before, constellations that have been covered in the blog are shown in blue (Ursa Major, Ursa Minor, Boötes, Libra, Corona Borealis, Hercules, Ophiuchus and Serpens, and Scorpius), with other constellations in red.  Saturn is being lost in the west, so if you want to observe Saturn, you'll have to do it in evening twilight, though if you look east starting at about 1 AM, you can see Jupiter rising.  As always, constellations we have yet to cover are in red.

.....August is most notable for the Perseid meteor shower (on which more later).  In short, during the first part of the month, meteors will be more common, many of them seeming to track from the northeast and the constellation Perseus.  Try to squeeze out meteor observing early, though, because while the meteor shower peaks on the night of August 11th, so does the full Moon.

The Best Meteors of the Year ... Darn It!

.....The most reliable meteor shower of the year is the Perseid meteor shower, usually peaking on the night between August 11th and August 12th.  In younger years, this was the one time during the year that I could get the whole family as interested in astronomy as I was, a situation that I found was pretty common.  In recent years, I have often held public observing sessions, which have turned out really well, as there is no bottleneck at the telescopes; meteor observing is laying back, getting comfortable, and trying to keep as much of the sky as possible visible to see shooting stars.  Easy to set up, and enjoyed by all.

.....I'm not doing that this year.

.....Let me explain why.  Every dark, moonless night not dominated by city lights, we can expect to see a few shooting stars per hour, flashing randomly across the sky. These typically come from one of three sources: Leftover bits of flotsam and jetsam that have been floating around the solar system for the last five and a half billion years (cool), little bits that have been boiled off of comets as they passed around the Sun (also cool), or nuts/bolts/heat shields/tool boxes that have come off of space craft and are crashing back down to Earth (less cool).

.....Each time a comet passes through the inner solar system, if it still has much of its original ice, that ice will boil off, taking some dust pebbles with it, and the ice will reflect sunlight, resulting in the bright coma and tail. What happens to this once the comet goes back to the outer reaches of the solar system? Nothing. That comet rubble stays in orbit, resulting in the comet's orbit eventually becoming a dusty tube of gunk around the Sun. If the Earth should pass through this gunk, then when the particles hit the Earth's atmosphere they will light up from the heat of friction generated from going from a temperature of less than three hundred degrees below zero (Fahrenheit) to thousands of degrees. Since all of these meteors are coming from the same general area in space, they will appear to come from the same general area of the sky, meaning that the meteors will all seem to radiate out from the same point. (Called, reasonably enough, the "radiant".)

.....Each August, the Earth passes through the remnant trail of the comet Swift-Tuttle, generating the Perseid meteor shower because the radiant of the meteors (the dotted circle in the image below) is in the constellation of Perseus.  Meteor showers do not require a telescope or binoculars; just go outside and look (in this case to the northeast, especially after midnight).

.....A lot of this is part of the standard run up to a meteor shower.  What makes this year different is that the meteor shower peaks only about a day before the full Moon.  Looking at different sources, the number of meteors per hour for the Perseid Meteor shower is usually given as a number between 60 and 120.  (Wow!)  Now let's look at that as the sky gets brighter due to the Moon.  Even if we take the most generous version, that considers that we can see all the way down to our eyes limit.  With the bright Moon, we can't.  With an interfering Moon, even if we could see down to fifth magnitude (as opposed to sixth magnitude, our limit), we would go from 120 down to about 46.  The full Moon is much more limiting than this, however.  Even if we assume a third magnitude limit, we're down to about seven.  Per hour.  With any bad or humid air, this could limit us to second magnitude (maybe three meteors an hour, if we're lucky), or first (maybe three meteors every four hours).  This is enough of a enthusiasm-killer that it's better to look to next year, when the moon will be much less troublesome.

.....Looking for Perseids can still be done in the nights leading up to Thursday night, but the Moon will drown out most of them.  Here is a map of the northeastern part of the sky on Thursday at about midnight.

The Best Meteors of the Year ... Darn It!

.....The most reliable meteor shower of the year is the Perseid meteor shower, usually peaking on the night between August 11th and August 12th.  In younger years, this was the one time during the year that I could get the whole family as interested in astronomy as I was, a situation that I found was pretty common.  In recent years, I have often held public observing sessions, which have turned out really well, as there is no bottleneck at the telescopes; meteor observing is laying back, getting comfortable, and trying to keep as much of the sky as possible visible to see shooting stars.  Easy to set up, and enjoyed by all.


.....I'm not doing that this year.

.....Let me explain why.  Every dark, moonless night not dominated by city lights, we can expect to see a few shooting stars per hour, flashing randomly across the sky. These typically come from one of three sources: Leftover bits of flotsam and jetsam that have been floating around the solar system for the last five and a half billion years (cool), little bits that have been boiled off of comets as they passed around the Sun (also cool), or nuts/bolts/heat shields/tool boxes that have come off of space craft and are crashing back down to Earth (less cool).

.....Each time a comet passes through the inner solar system, if it still has much of its original ice, that ice will boil off, taking some dust pebbles with it, and the ice will reflect sunlight, resulting in the bright coma and tail. What happens to this once the comet goes back to the outer reaches of the solar system? Nothing. That comet rubble stays in orbit, resulting in the comet's orbit eventually becoming a dusty tube of gunk around the Sun. If the Earth should pass through this gunk, then when the particles hit the Earth's atmosphere they will light up from the heat of friction generated from going from a temperature of less than three hundred degrees below zero (Fahrenheit) to thousands of degrees. Since all of these meteors are coming from the same general area in space, they will appear to come from the same general area of the sky, meaning that the meteors will all seem to radiate out from the same point. (Called, reasonably enough, the "radiant".)

.....Each August, the Earth passes through the remnant trail of the comet Swift-Tuttle, generating the Perseid meteor shower because the radiant of the meteors (the dotted circle in the image below) is in the constellation of Perseus.  Meteor showers do not require a telescope or binoculars; just go outside and look (in this case to the northeast, especially after midnight).

.....A lot of this is part of the standard run up to a meteor shower.  What makes this year different is that the meteor shower peaks only about a day before the full Moon.  Looking at different sources, the number of meteors per hour for the Perseid Meteor shower is usually given as a number between 60 and 120.  (Wow!)  Now let's look at that as the sky gets brighter due to the Moon.  Even if we take the most generous version, that considers that we can see all the way down to our eyes limit.  With the bright Moon, we can't.  With an interfering Moon, even if we could see down to fifth magnitude (as opposed to sixth magnitude, our limit), we would go from 120 down to about 46.  The full Moon is much more limiting than this, however.  Even if we assume a third magnitude limit, we're down to about seven.  Per hour.  With any bad or humid air, this could limit us to second magnitude (maybe three meteors an hour, if we're lucky), or first (maybe three meteors every four hours).  This is enough of a enthusiasm-killer that it's better to look to next year, when the moon will be much less troublesome.

.....Looking for Perseids can still be done in the nights leading up to Thursday night, but the Moon will drown out most of them.  Here is a map of the northeastern part of the sky on Thursday at about midnight.

Why I hate Microsoft's Spellchecker

.....The constellation of Scorpius (the Scorpion) appears in the southern sky at this time each year, as seen from the Northern Hemisphere. There are several myth explaining this constellation; of them, one holds that this is the scorpion that killed Orion the Hunter, thus explaining why the two constellations can never be seen in the sky together. (There is more than one story concerning the death of Orion, so this may explain why Aesculapius is credited with bringing Orion back back from the dead to be killed in more interesting ways by the gods. I've had days that felt like that.) A different myth from Hawai'i explains that this constellation is Maui's fishhook, which got caught on the bottom of the ocean and dredged up the Hawaiian Islands.

.....There have some good news, and I have some bad news ... oh, what the heck, I'll start out with the good news, everybody likes good news ... Scorpius has a number of bright stars, and it's basic pattern (a scraggly line) is fairly easy to follow. Furthermore, as we will see on our next cycle through the constellations, Scorpius has a number of bright star clusters, and some of them look very attractive through binoculars. (Two bright open clusters can be found by looking just to the northeast (up and left, on the map) of Shaula and Girtab. these are labeled as M6 and M7, and they are quite nice sights in binoculars or a telescope. This is not a surprise, as the summer Milky Way goes through Scorpius and Sagittarius, and covers most of these constellations. In fact, on this map the center of our galaxy is about 30,00 light years away, in a direction just north of M6.

.....The map below shows Scorpius on our "standard" sized maps, with a radius of 30 degrees (where the angular distance across the sky from the end of a fully extended pinky to the end of a fully ectended thumb, held at arm's length, is about 15 degrees.

.....Let's zoom in a bit (the radius of this image is 20 degrees) so that the traditional star names clearly refer to their associated stars, and we get a bit of a closer view.

.....The bad news is that Scorpius is located far to the south in the sky. In the northern hemisphere, Scorpius spends less time above the horizon, rising in the southeast (instead of the east), and setting in the southwest. On the chart below, I am showing the approximate horizon for Scorpius, at its very highest, for a selection of American cities. (If you don't live in one of these cities, go by latitude.) For areas that correspond to the northern United States (Philadelphia is at about the same latitude as Beijing, and is actually south of Istanbul), Scorpius is only fully above the horizon for a brief time. Add to this that this map assumes an uncluttered southern horizon, so that any trees, hills, or Pump 'N Munches will interfere with that, and that when looking that low on the horizon you are looking through more than five times as much, wobbly, humid, dusty air as when you look straight up, observing Scorpius can feel like you are trying to do so from the bottom of a swimming pool.

.....So if you are living in the continental United States, or at comparative latitudes (in Asia, the horizon of Karachi, Pakistan would be roughly equivalent to Miami), then the existence of the stars in the highlighted area will simply have to be taken at my word.

.....Now if you have gotten your knowledge of the sky from a newspaper column across from Family Circus, or if you are a spellchecking program, you may have been subconsciously changing the name of the constellation to "Scorpio" but that's not its name. Spread the word, okay?

Snakes! Why'd It Have To Be Snakes?

.....One of the largest constellations in the summer sky is actually two constellations. In another sense, it could be thought of three constellations. Technically, the constellation of Ophiuchus is the Serpent Bearer, and the constellation of Serpens, the serpent that he his carrying/wrestling with. Here is a map of the constellation:

.....And below is the representation of this constellation as Johann Bayer drew it in the star atlas Uranometria, in case my description of the constellation didn't make sense to you ...

When illustrating a figure named "man wrestling giant serpent" it is a wise artistic move NOT to show from the front.

.....which would be reasonable, as while most constellations at least make some sort of surface level of sense (the hunter, the scorpion, the northern crown, the swan, ...) what the heck is up with "the guy holding snake"? When does that make sense?

.....Here's where the problem comes in. Suppose that it is not a good night, and the limiting magnitude is 2.00. (This would be a really bad night in the country, but if you live somewhere with a lot of streetlights, this could come into play as a bright night or if that part of the sky is over some of these lights.) In that case, you see nothing in this area.

.....With a little better sky, and a limiting magnitude of 4.00, at least the "house" shape of Ophiuchus shows up. Serpens is largely invisible yet, and since there are no real patterns in Serpens, just a "scraggly line of stars", this constellation is still invisible. (On our next pass through the constellations, next year, this does at least give us bright stars to allow us to start finding all of the bright globular clusters in these two constellations.)

.....We need to be able to see all the way down to fifth magnitude in order to make out the patterns of Ophiuchus and Serpens. On the map at the beginning, for this constellation I had to show stars down to sixth magnitude in order for the patterns to be apparent.

.....All of this can distract from the basic oddness of the constellations themselves. I'm not referring to Serpens being split in half, with Serpens Caput (the head) and Serpens Cauda (the tail), but the story of the constellation itself. The constellation group seems to be so old that there is not "a" story associated with the stars, but a "well, I guess it means..." explaining the large pattern of a guy wrestling with a snake. The most common explanation is that the star group represents Aesculapius, the son of Apollo who became so proficient at medicine that he could bring the dead back to life. (One of his subjects was Orion the Hunter, or this could be a Classical retconn to account for the two different legends of Orion's death.) This, as one might guess, is one of the fast ways to land you on the gods' &^%$ list, so he was immediately struck down and placed in the heavens. The serpent has represented the medical profession (including the intertwined serpents of the Caduceus) because the ancients saw the snake shedding its skin and got the idea that the snake could therefore regenerate its way to immortality, a feat actually reserved for Timelords. There are many, many other myths that have been attached to these stars from " Hey, maybe it's Izhdubar opposing Tiamat" to "Hey, let's change it to Saint Benedict among the thorns".

.....I was going to now try and see if I could find some other pattern among the stars that might be more recognizable than, well, something that no one has recognized, when Anne Marie walked behind me and asked, "Which constellation is the frog?"

.....Frog? What the heck are you talking ...

.....Well, blast.

.....Lastly Ophiuchus is actually the thirteenth constellation of the Zodiac, as the path of the Sun crosses that little leg sticking out of the bottom. Ophiuchus actually contains the Sun from November 30th until December 17th. Scorpius only contains the Sun from November 22nd until November 29th. (Yes, neither of these match up with what the columns in the newspapers say: those are based entirely on the Babylonian religion of 2500 years ago, and have slightly less reliability than, say, Charlie Sheen.

The July Sky

.....The was a bit of a blip posting this, so here is the correct version.

.....Below is shown an image of the night sky as it is at ten PM in early July (corresponding to nine PM in mid-July, and eight PM by late July.  We can now start to see how the sky changes over time by comparing the sky in July with the sky in June (also shown below).

 

.....As before, I have included constellations that have already been discussed (Boötes, Ursa Major, Libra, Ursa Minor, and the asterism of the Summer Triangle) as well as some constellations that will be coming soon, such as Ophuichus and Serpens, Scorpius, Sagittarius, Lyra, Aquila, and Cygnus).  Note that on the maps below, the points of the compass are shown as on the maps above.  To see these constellations, take your computer (or print out the map, totally your choice) and turn it so that the labeled north (south, east, west, whatever) is at the bottom of the map when you are looking north (south, east, west, whatever.

.....The summer sky can illustrate a couple of different points.  The map below shows all stars theoretically visible, all the way down to sixth magnitude.  There are two reasons why I don't use this map for my basic sky map; sadly, the vast majority of people don't get to see the sky like this (I did, last week, and I'll be writing about that tomorrow), and if you did see the sky like this, it might well overwhelm even a fairly experienced suburban skywatcher.  Also on the map below, you might note that there are more stars in the eastern sky than the western sky, and that there almost seems to be a band going from the south to the northeast.  This is the summer Milky Way with the center of our galaxy between Scorpius and Sagittarius (and then another 30,000 light years), so hopefully this makes sense.

.....This map assumes that the reader can see stars of fifth magnitude or brighter.  This is still wildly optimistic for most people, but as you will see, I kind of need to go to this level in order for the patterns as generally associated with the constellations to make any sense.

 .....This map shows the sky to a limiting magnitude of fourth magnitude (remember that the lower the number, the brighter the star).  Holes start to appear in the constellation patterns.

 .....If the sky is cloudy or bright enough that nothing fainter than third magnitude can be seen, then only the larger patterns (such as the Summer Triangle) can be seen.

 .....Now that only second magnitude stars or brighter are shown, then only the brightest stars appear, but it is still enough to allow you to orient yourself.

.....If first magnitude stars are visible, one might wish to go back inside and expand your mind or hang out with loved ones, or, at this point, just watch some TV.

.....Finally, it could be completely cloudy: