Moony Monday!

.....I said "Moony Monday" for the Total Lunar Eclipse that will occur early Tuesday morning because I couldn't think of anything that went with Tuesday. The universe is not rewarding this, however, since there is a winter storm warning with 5-8 inches of snow on the way, finishing up with frozen rain. I hope someone else out there gets a chance to see this.

.....To see this, all you need is a good view of the skies (from the Americas, and best set up for North America). If you have a telescope, or even binoculars, that will make things even better, but it isn't necessary.

The first stage is when the Moon enters the Earth's penumbra, the shadow where part of the Sun, but not all of it, is blocked. This will be pretty much undetectable. The Moon enters the penumbra at: 11:46 PM (CST/ UT -6, which is 12:46 AM Tuesday in the Eastern Time Zone, and 10:46 PM in Mountain Standard Time, and so on.)

.....The Moon enters the umbra, the central shadow at 12:51 AM (again, CST, the best time zone) , and totality, with the Moon entirely in the umbra from 1:57 AM to 3:14 AM. On Earth, a total eclipse is completely dark, but in a lunar eclipse the light passing through the Earth's atmosphere is scattered into the shadow. In the same way that the sky appears blue because blue light is scattered first, and the setting Sun appears red because red light is scattered last, the totally eclipsed Moon will appear a deep red, sometimes getting so faint that the full &^$%&^% Moon is hard to find in the sky.

.....The Moon leaves the umbra at 4:17 CST, so the party is then pretty much over.

.....Since this lunar eclipse happens on the Winter Solstice (when the Sun is at its lowest point in the sky), the Full Moon (exactly on the opposite side of the sky) will be at its absolute maximum possible highest. I'm honestly fairly amazed that no group has come forward claiming some mystic significance for the occasion. There is definite non-mystic significance, because this is the last total lunar eclipse visible from North America until April of 2014.

.....If you do get a chance to see it, please let me know; I'll be watching the snow fall, grading final exams.

An apology

.....Wow, looking at the time that has gone by, while I very much want to provide a blog that is aimed at those who might not be in the middle of the country with years of experience, I've first gotta go with my teaching responsibilities. Still, I am working toward building up a "Year around the Sky" to start in May. I will still be updating this as often as I can.

Aquila: The Eagle Has Landed

..... The southern star in the summer triangle is Altair, which means "the Eagle". (Vega, in Lyra, also means "the [Diving] Eagle.") Altair is the brightest star in the constellation Aquila (the Eagle) which is shown in the map below along with the constellations Sagitta and Scutum, which a reasonable reader at this point might conjecture mean "the Eagle" and "the Eagle", respectively, but surprisingly this turns out not to be the case.

.....Altair is the closest of the stars in the Summer Triangle, being about 16.77 light years away. The light that reaches the Earth on the night of September 20th, 2010, left the surface of Altair on December 13, 1993.

.....The constellation Aquila is a fairly large constellation in the center of the summer(/autumn) Milky Way. The view of the Milky Way in the sky even shows a split, with the Milky Way having apparently separated into two bands. This appearance is actually due to tremendous clouds of neutral hydrogen gas and dust between us and the center of our galaxy. We're looking in the direction of a tremendous number of stars, which makes it surprising that Aquila has no deep sky objects of interest in the reach of a small telescope.

.....This lack of cool stuff is why I added the constellations of Scutum and Sagitta to this map; I'm going to describe the telescopic objects in these two constellations in Aquila's place, since Aquila is easy to find, but doesn't have anything of its own.

.....This constellation also stands out to me because I now live in an area in which eagles are reasonably common sights. Just last weekend on our drive along the Mississippi to town, we saw two eagles flying over the road. Upriver in Wabasha is the National Eagle Center, located here because it is the northernmost point along the Mississippi the does not freeze over, so there are many bald eagles that winter in this area. In January and February it is possible to see dozens of eagles along the river, and I don't think that there has been any times in which I have gone there that I have not seen any eagles in wild.

Deep Sky Objects in Lyra (L2/M57, M56)

.....There are two Messier objects in Lyra, and the up side to Lyra's small size is that I can fit the entire constellation figure on the finder chart for both objects. Lyra contains one of the most impressive, and easiest to find, Messier objects.

Messier 57 / Leckenby 2: The Ring Nebula

.....The Ring Nebula, aka M 57, aka NGC 6720, aka L2 (my designated second object on the "Leckenby list", my list of deep sky objects that a starting observer has a really good chance to locate) is located between the bottom two stars of Lyra, Sulaphat and Sheliak. In a good pair of binoculars, the Ring Nebula can be seen a little bit closer to Sheliak than Sulaphat.
...In a telescope, the Ring appears as a, well, ring. The Ring Nebula is a "planetary nebula" (due to its round appearance), and in the simplest model of a planetary nebula, it represents what will someday happen to the Sun. When nuclear fusion finally stops at the core of the Sun, the core will collapse without that energy being added to it, and that collapse will release energy that will bounce off the outer part of the Sun like an expanding soap bubble. As it turns out, things are a little bit more complex; the Ring isn't actually a spherical bubble of gas, but more of a cylinder that we are looking at edge-on.

.....Below are two images, one of which might be a mistake to include. The one on the left is a sketch I made of the Ring Nebula through my personal telescope. This is probably fairly close to how this object might look to the typical backyard observer. The other image is a Hubble image of the Ring. This object will *never* look like this in your backyard, I'm sorry.

Messier 56

.....Messier 56 isn't viewed as often as, say, the Ring Nebula, because M56 is a globular cluster, and there are dozens of globular clusters visible during the summer. Given a choice between M56, and something like the Hercules Cluster or M5 in Serpens, most people will go for one of the biggies. The most dramatic globular clusters appear as a bright central blur that resolves itself into individual stars as you get farther to the edge. That resolution does not appear with M56, at least it didn't with me. (The seeing the last night I looked at it was not the clearest, however.)

.....the Messier Objects were originally compiled into a list by Charles Messier because he was looking for comets, and these were things that kinda looked like comets, but weren't. Author Stephen James O'Meara has noted that M56 is special to him because it has a hazy, comet-like appearance, so it shows what Messier found distracting when he made a list of what we now recognize as a tour of the wonders of the sky when Messier was just trying to list the garbage that kept getting in his way.

Lyre, Lyre

.....Lyra the lyre is the first of the constellations of the Summer Triangle; a small constellation consisting of a triangle of stars joined to a parallelogram, but easy to find because it contains one of the brightest stars in the sky. The westernmost star in the Summer Triangle is Vega, and when you can see it over the horizon it the fifth brightest star in the sky. (If someone is reading this over your shoulder, they probably made some joke like, "except for the Sun, dude." I'll wait for a second if you choose to slap them.)

(All good? Yeah, I feel better, too.)

.....Vega is actually one of the stars we use to define the "magnitude" scale that defines the brightness of stars. Originally, this system goes back to the Greek astronomer Hipparchus, who defined the brightest stars as "stars of the first rank" and the dimmest stars as "stars of the sixth rank". Now that we can use cameras to measure exactly how much light we receive from a star, it is now possible to be a little bit more precise. Vega and Arcturus (in Boötes) were use to define zero magnitude. In this reconstructed system, stars with a magnitude of 1.00 are bright, stars with a magnitude of 6.00 are just barely visible one a clear, dry, dark night, and the Sun has a visual magnitude of -27.
.....The only stars brighter than Vega are Arcturus (just barely), Sirius (a winter star), and Canopus and Rigil Kentaurus (stars not visible from the middle and upper United States).

.....The second brightest star in Lyra, Sheliak, is special in another way. Like most stars, it does not travel through space on its own, but Sheliak is actually two stars orbiting closely to each other. As I said, most stars travel in pairs (or more), but these two stars are orbiting so closely to each other that the shape of both stars is distorted, and material is apparently escaping out of the "back end" of Sheliak A. Incredibly funky physics, but you can't see anything through a telescope.

.....What you *can* see in a telescope is Epsilon Lyrae, the other star in the triangle at the top of Lyra. This might look a little funny in the star map, and this star in even a good pair of binoculars will be revealed as a pair of stars. If you then look at Epsilon Lyrae in a telescope under high power, each of these stars is revealed as another pair of stars; Epsilon Lyrae is known as the "double-double" star, four stars (two pair) appearing as one.

.....Numerous times in the past, I have shaken loose from the constellations of the past merely held on to because, ooh, the ancient Greeks created all of western civilization, big whoop, so as I proposed in my last post, I'm replacing the lyre with the lyrebird. After all, how many of us own harps in this day an age? I myself only have one CD of harp music. Hey, it was at a concert; support artists, art establishes and maintains the common culture! You like culture, right? (If you are next to someone who answered no, remember, engineers are often helpful to society as well.)

NEXT: Telescopic objects in Lyra

The Birds of Summer

.....One of the problems that can keep people from moving from a peaceful contemplation of a dazzling array of stars to finding the dazzling variety of clusters, nebulae, and galaxies that are surprisingly accessible once you make the shift from seeing the sky as a featureless expanse of stars to recognize patterns that will allow you to find wonders hiding in plain -er- slightly assisted sight.

.....Starting in the summer (but lasting until November), three of the brightest stars in the northern sky form a (duh) triangle that covers much of the sky. This "triangle" that first appears in the "summer" sky is called the Summer Triangle because at some point, astronomers got tired of doing things like grabbing a rough pentagon of fourth magnitude stars and calling it "the giraffe"

.....The three bright stars are in three different constellations because the Summer Triangle really does cover a large selection of the sky, and ancient astronomers invented constellations to be able to break the sky into manageable pieces, so they weren't going to invent constellations that tokk up most of the sky. Well, not more than once, anyways. The three bright stars are Altair, Vega, and Deneb, in the constellations of Aquila, Lyra, and Cygnus (the next three constellations I'll write about), and you can use these to do a bit of traveling into the past. Altair, the southernmost star in the triangle, is about 16.8 light years away. This means that it has taken the light from Altair more than sixteen years of traveling through space. The light that reaches us on Friday left Altair about November 12th, 1993.

.....In the northwest, the brilliant star Vega appears to be a step brighter than Altair, but it is actually giving off more than four and a half times as much light into space than Altair does, but Altair is closer. Vega is 25.3 light years away, which mean that Friday's light from Vega left about May 2nd, 1985.

.....The third star, Deneb, is the faintest of the three as seen from Earth, but it actually gives off more than 60,000 times as much light as the Sun does. If we wanted to move Earth to Deneb and get as much light as we do now, we would have to move the Earth to be seventeen times as far away from Deneb as Pluto is from the Sun. Deneb is more than three thousand light years from our solar system, meaning that the light we see now has been traveling through space since 1218 BC, when Ramses II (the Great) was Pharoah of Egypt, and the Trojan War was going on*.

.....These three constellations will be the next three that I write about, Cygnus the swan, Aquila the Eagle, and Lyra the Lyre ... y'know, since two of these three are birds, and since I have felt no compunction about changing constellations, let go ahead and change Lyra to the Australian Lyre-bird, and have these three as as the birds of the Summer Triangle. There are a couple of small constellations that will also show up: Sagitta the arrow, located inside the Summer Triangle, and Scutum, the shield, which I will discuss along with Aquila the eagle, because Aquila has no Messier objects of its own.

* or at least this falls into the range of time in which the original Trojan War took place.

The Moon in the Sky

.....In response to a couple of questions, I've tried to come up with a device that would help one work out when the Moon will rise and set, and what part of the sky it will be in for any given time of day. This is my result. First, start with the base of this ("Lunalabe"? ""? I need a better name for it), a wheel that another, smaller wheel will move in.

.....Once that is done, find a way to attach this smaller wheel so that the two wheels have a

common center. The way that I first did this was to use a paper clip; an alternative would be to go to a craft/scrapbooking store and buy a specialty brad which can attach through the center. Perhaps it would be better to use an eyelet, or something that has less of a chance of ripping - we're really at the end of my know-how on this subject, but you can check out my crude attempt in the photograph below.

.....Here is how this works, if you know the phase of the Moon, or when the new and/or full moon is that month (you can find these on many calendars, plus, I will now begin posting that information at the beginning of each month. For August, 2010:

Last Quarter: August 2

New Moon: August 9
First Quarter: August 16

Full Moon: August 24

The lunar month is 29.5 days long. This means that the time between phases is roughly one week, which we can use to find the Moon between these dates. Consider this Friday, August 20th. This is midway between First Quarter and the Full Moon, so we start by looking on the wheel between the First Quarter and the Full Moon. The Moon between the New Moon and the Full Moon is waxing (increasing), and the Moon between First Quarter and Last Quarter is gibbous, so the phase of the Moon on Friday will be "waxing gibbous". This has a "+9" by it, which means that the Moon (all else being equal) will rise, set, everything, nine hours after the Sun does. If we take as an average that the Sun rises at 6 AM, gets as high in the sky as it is going to get (transits) at noon, and sets at 6 PM, this indicates that on Friday, we should expect the Moon to rise at 3 PM, transit at 9 PM, and set at 3 AM.

.....This is where we also have to look at the outer wheel. Line up the lines representing the direction of the Sun (the wheel works because as far as the Earth and the Moon are concerned, the Sun is so far away that it is not a point to examine in perspective, but a direction) is coming from "August". (This also shows that in late August the Sun is in front of the stars of the constellation of Leo.) Imagining a line from the center of the wheel out to the constellation ring, the Moon on August 20th should be in front of the stars of Sagittarius. Sagittarius has a "-2" next to it, because Sagittarius is far to the south, and so this constellation is not above the horizon as long as the others. (The Sun is in Sagittarius in December and January, and the Sun is not above the horizon as long as it is in later months.) The "-2" means that in this constellation there will be two hours less time above the horizon at rising and setting, so we expect to Moon on Friday to rise at 5 PM, transit at 9 PM (this does not change), and set at 1 AM. If we compare this to the actual times, the Moon will rise at 6:01 PM, transit at 10:30, and set at 3:03. This seems wrong, if you don't take that hated Daylight Savings Time into account.

.....Tell you what, during DST, just shift your predition forward one hour, so our expected times are Moon rise at 6 PM (pretty close), transit at 10 PM (close-ish, I make no promises to be exact), and Moon set at 2 AM (admittedly sketchy - I might need more work on the hour modifiers on the outer wheel). Still though, this first version does provide a decent rough time, and it identifies where the Moon will be in the sky well. You can use this to help learn the constellations along the path of the Sun and Moonin the sky (the zodiac), as long as the Moon is not too bright.

.....On the other hand, if you see the Moon in the sky and you recognize its phase,this can be used to find rise/set times from that as well. This (I certainly hope) will help you find the Moon in the sky, and this will tell you what constellation it is in.

.....Please let me know if there is a feature that you would like the wheel to do that you do not think that it does, or if there is a feature that is too distracting. If you would like to try this, I have the images as two pages in a PowerPoint presentation at this site.

.....SPECIAL NOTE FOR TEACHERS. I use this device in class to try to illustrate the relationship between the Earth, Moon and Sun defines the appearance of the Moon. If you would be interested in something like this, please let me know, and we can compare notes.

The Perseid Meteor Shower, 2010

.....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.

.....The Perseid meteor shower does not require a telescope or binoculars; just go outside (especially on the nights of Wednesday, August 11th and Thursday, August 12th, and look to the northeast (especially after midnight).

.....Of the the backyard astronomy I have done, I have a special regard for the Perseid Meteor Shower. Because it does not require special equipment, special practice or special skills, it is easy to share with others. (Also, since observing the Persieds is just looking at the sky, there is no "one person at a time effect that you get with a telescope.) Last year, one of my friends told me about taking his son outside to see the meteors. I've gotten other mail about people who have had their parents show them the meteor shower, and have then shared it with their children. For me, the Perseids were one event I could most easily drag people out to see, often going to visit family with dark skies, or just setting up lawn chairs behind the house, or (one time) my parents even took us to a state park to watch the meteors. For me this gives the Perseids a fairly personal level, especially since my father passed away two and a half years ago. When I would have my telescope at home, it would always be easiest to interest my Dad in coming out and looking at the sky, so there were a lot of times he (and others) would come out, but the Perseids could get everyone out, so its something of a family holiday in my book. I hope that you have the opportunity (weather) to give it a try this year. There will be no bright moonlight those nights, so the sky should be quite dark.

.....Here is a map of the northeastern part of the sky on Thursday at about midnight. Please let me know if you have traditions about the Perseids, or if you have a chance to observe them! If you are in the Winona, Minnesota area, there will be a public observing session at Saint Mary's University of Minnesota. Turn in at the lower gate (across from Goodview Road) and drive straight (i.e., don't make any turns) to St. Yon's Hall. We will set up on the field next to St. Yon's. Bring your own chair/blanket/keep-my-rear-end-dry-device!

Objects in Hercules: The Leckenby List Begins

.....The constellation of Hercules is pretty large, sprawling through a fairly dim part of the sky, and it contains of number of excellent deep-sky views. Four of these make good targets even in the light-polluted skies that most of America now has. Two of these appear on Charles Messier's list of Messier Objects, one is a fairly obscure open cluster, and one is a planetary nebula.

.....Let me take a moment to look on the catalogs that we are using. The two globular clusters (the first among many, many of these types of clusters visible during the summer) are best known by their Messier designations, although there a lot of catalogs in astronomy because, hey, there's a lot of stuff. If some new object is identified, generally it is listed in the next catalog instead of bringing the old one up to date (the Messier Catalog itself is an exception to this). The Great Cluster in Hercules is known as M13, NGC 6205, GCI 45, 2MASX J16414163+3627407 (what it gains in precision it loses in convenience), and now (at least as far as this blog is concerned), L1.

.....There are, clearly, many different catalogs. Why add one more? What possible use could this "Leckenby List" be? When I first started observing, in seventh grade, with a "telescope" on a tripod that I had to balance on the bar of our chain link fence, I tried to use the Messier Catalog as a guide for objects to find. After all, most of the bright objects in the sky are in the catalog, but not all of them are. I wanted to set up a list that had all the cool things that one could find with a small, suburban telescope, and the Messier Catalog left stuff off that list. There is another Catalog that is of recent vintage, the Caldwell-Moore Catalog, set up to include cool things that Messier left out, but like the Messier Catalog, that also includes objects that are too faint, or too diffuse to be seen in light-polluted skies. The Leckenby List will try to include interesting things that can be seen by a fairly new observer on a perhaps somewhat sketchy night. That's my goal.

.....Globular clusters are actually outside of the disk of our galaxy (while they do orbit the center of the Milky Way), and they consist of some of the oldest stars we can see, forming before the stars in the disk of the Milky Way began to collect.

M 13 or L1

..... The Great Hersules Cluster is one of the two best globular clusters as seen from the continental United States. (If anyone is reading this from southern Florida or Texas, please don't bring uop the much larger and brighter globular cluster Omega Centauri. Thanks.) Tghe Great Hercules Cluster has more than three hundred thousand stars, and it so large that light takes more than 130 years to pass from one edge of the cluster to the opposite edge. It is only that the cluster is at a distance of 23,400 light years that keeps it from appearing even more impressive. M13 is fairly easy to find. Looking at the keystone of Hercules, start with zeta Herculis, one of the stars at Hercules' waist, and scan north. When you are most of the way to eta Herculis, the Hercules Cluster will appear as a fuzzy spot between two stars that sppear brighter than their neighbors. M13/L1 is visible even in bionoculars, which is one reason why I have included it as the first object on the Leckenby List.


As seen in a small telescope, M13/L1 appears as a tight ball of stars, with the stars near the edge (where the density of stars starts to thin out) clearly resolvable as indivindual stars, while the stars near the center blur together). To my view, there are a couple of "arms" of stars that appear a little denser than the other areas (although to be fair, photographs show the stars as pretty uniformly distributed). I would be very interested if there were anyone else out there who had an opinion on whether their own observations showed anything like this.





M92


M92 is the other Messier Object in Hercules, and it is also a globular cluster. This can be found fairly easily by starting at the northeast corner of the keystone. If you are looking at this star in binoculars or in a telescope's finderscope, you will see two stars next to pi Herculis, and a set of bright (in binoculars) stars forming an asterism that I christen "the l'il kid" reaching up above his/her head (the existing stars in the star pattern prevent a greater level of detail in the gender of the figure) for the asterism that I name the "Trademarked Fying Disk Toy" (I don't want to get sued), and abovve that, M92 as a ball, these two objects apparently stuck on an invisible roof that the l'il kid just can't reach.

.....Sadly, I haven't observed M92 nearly as much as M13/L1, so I have less of an idea of it's individual observing character. M92 is about two-thirds the apparent size of M13/L1, while only being a little (comparatively) farther away

DoDz 9

.....The next object to look at is a small cluster labeled as Dolidze-Dzimselejsvili 9 is a group of about fifteen stars. Honestly, I do not know if this is an actual cluster of stars that all formed together, or if this is just how it appears. Even the name does not help that much because the DoDz list only has nine objects on it, and the list itself is pretty obscure. Start with the end of Hercules' western arm, and even binolculars should show you this cluster (I think).

.....This is my diagram of this cluster, and I couldn't find a photo or setailed chart to let me know if I was even looking at the right stars. Does someone else have a take on this?

NGC 6210

.....The fourth object is NGC 6210, deriving its lovely, poetic, name from the New General Catalogfrom the 1840's, so called because it replaced the "General Catalog of the 1820's. So there. Nebulae of all types are often hard to see from suburbia as light that is smeared across the sky can be more easily drowned out by the local Wal-Mart (sadly, there's always a local Wal-Mart) that light concentrated into points (stars). Planetary nebula are even more rare because they are the bubbles of ejected gas given off by stars around the same mass as the Sun as those stars finally go the Great Retirement Home in the sky (which is, at least, actually in the sky). These bubbles are often round, as soap bubbles are, and this round(ish) appearance gave them the name "planetary nebulae".

.....I have a finder map for this object that do not have the constellation lines on it because those lines can interfere with finding the object. If you can start from beta Herculis, you should be able to star hop to the nebula, although I don't have .

If you can get to where NGC 6210 shoul be, it should be observable as a small but distinct blue ring, the light concentrated enough to be bright enough to see and just large enough to be identified as a planetary nebula.

July Sky

.....While I work on the observing maps for some deep sky objects, I don't want to miss the forest for the trees, and so here is a sky map for July. (Constellations that have been discussed on this blog are in blue, and constellations I have not gotten too yet are in red.)

.....The Big Dipper is still in the sky, as it will always be in the sky from the northern US, but some constellations that you can find from the Big Dipper (Boötes and Virgo) are moving off to the west. In the east we can find the Summer Triangle, built using three of the brightest stars in the sky. This set of stars (despite its name) will be in the sky until early winter.

.....This map only includes stars brighter than fourth magnitude, so some stars in the constellations are "missing". If you are just learning the constellations, or if you are viewing from a light-polluted sky, I hope that this will be a better way to find the brighter stars.

.....Start making plans now for the Perseid Meteor Shower! Peaking on the nights of August 11th and 12th, this meteor shower can result in dozens of meteors an hour! This year, the Moon will be out of the sky on these nights, so the sky will be at its darkest. This will hopefully be a great year for the shower!

My Delays

.....I haven't gotten a second post up this month, something which was certainly not my plan. Here's my excuse: We went to my granmother-in-law's birthday party, came back, were visited by a good sized chunk of my half of the family for a week, and then went back and visited the in-laws in a more leisurely fashion. Soon (I promise) I will have up a post on things that a small telescope, operating under streetlights, can find and see in Hercules, then a post on the phases of the Moon, then a post on why working for a dark sky is also healthier, more environmentally friendly, and *safer* than sticking street lights every five feet. Then more constellations.

-- Harry

Hercules, or "There?", "No, next to it", "There?", "Kinda"

..........Hercules is a constellation of fairly dim stars surrounded by brighter constellations. One might consider just skipping over these stars, but there are some beautiful binocular and telescope objects located in this constellation (the subject of my next post), and these objects make the hunt worth the wait. These objects will also trigger the start of what I am modestly) calling the "Leckenby list". There are many different lists of deep sky objects, the most well known of those being the Messier Catalog, but much of my observing history has been from suburbia, where a lot of even the Messier objects are invisible in a small telescope, and where there are a number of other cool deep sky objects that Messier, for one reason or another, did not see fit to put on his list. There are other lists, such as the Caldwell list, that look at deep sky objects that are in the same range as the Messier list, just not recorded by him, and some bright, wide objects that these lists have considered as too obvious or outside their scope (rim shot), such as double stars. The Leckenby List is my list of cool sky objects that can be seen with a small telescope in suburbia. You don't have to go through what I did, hours of effort to find some object that I've been promised is there, only to discover that I am looking at it, I just can't see it.

.....It is the purpose of a later run through the sky to go into more depth on the story and legends behind the constellations. In any event, I will go under the assumption that if something makes Disney, the basics are fairly well understood.

.....(Although this movie left out Hercules killing his wife and children in a drunken rage. They must be saving that for the sequel.)




.....As far as that goes, if you're going to look for one of the popularizations of Hercules, I'd seek out the Steve Reeves movie versions from the late 1950's. These were brought to my attention by the Mystery Science Theater 3000 versions of Hercules and Hercules unchained, but if your standards are a little relaxed (three beers, or it is 4 AM in the morning, or some such) these movies are as good as any from the era and from the genre. Better than, say, Clash of the Titans (either version).


.....The constellation of Hercules can be found between the constellations of Corona Borealis (or, "The Kite-Eating Tree", if I can get that to catch on) which is relatively easy to find, and the constellation Lyra, easy to find due to the presence of the bright star Vega. (Vega and Arcturus are two of the brightest stars in the sky, and Hercules is roughly between them.) Find the constellation by looking for the two rhomboids that make up the central body of Hercules. The northern one, smaller and a little easier to find, is called the "Keystone", and this will be our starting point for two bright globular clusters in this area.

.....Looking at this, you may find the presence of Hercules less than obvious. That is, looking at this once you finally find it in the sky. (No slight is intended. I've been observing the sky since I was seven, and Hercules is on of those constellations that I have to find, as opposed to just jumping out at me. In fact, on the Mystery Science Theater 3000 episode in which Joel and the 'bots watch the first Hercules movie, they comment on how most of the constellations don't seem to make sense, and Tom Servo attempts to reframe the constellations in terms of modern sensibilities. (You can watch it at this link; the relevant segment starts at about 3:09.) In honor of Tom's work, I'm going to rechristen this constellation into our modern form (joining the Kite and the Kite-Eating Tree) as something that these stars resemble as much as they do any version of Hercules, I give you ...

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Pablo Picasso's Cubist masterpiece, "Guernica"

Libra: the Balance or the Scorpion Blocker

.....Libra is the first of the constellations along the Zodiac that I have written about here. (A curious reader might look at the current star map and wonder why I didn’t start with Virgo, much higher in the sky right now; the reason is that I am not just working my way around the sky, but that on this first pass I’m centering on the brightest of deep-sky objects, things that can be seen with a small telescope. Of the various types of deep-sky objects, the hardest to view are galaxies, and Virgo is so chock full of them that I am saving this constellation for last.)

.....What is the Zodiac? Well, the ecliptic is the path that the Sun takes through the sky, and the planets all stay within 7° of this line (If we skip Mercury, all the planets are within half this distance of the ecliptic). The ecliptic passes through twelve constellations (traditionally; as the constellations were given boundaries by the International Astronomical Union in 1930 the ecliptic passes through thirteen constellations), and these constellations are the Zodiac. Besides being the only zodiacal constellation with no Messier objects, Libra is also the only zodiacal constellation named after an inanimate object.

.....Our constellations can be traced back to the forty-eight the Greeks had (there are eighty-eight constellations now), but the constellations of the Zodiac are much older. This makes sense because while many of the constellations can be thought of as “sky-decorations” the Zodiac allowed the ancients to track the seasons. Of the zodiacal constellations, Libra might one of the youngest.

.....Libra as the balance represents that the Sun would be in this sign at the Autumnal Equinox, when the day and night would be equal lengths, or at least it was. According to the boundaries as they are now, the Sun would be in Libra at the equinox from about 2200 BC until about 700 BC. Even when not using the strict modern boundaries, the wobble of the Earth around its axis (which I discussed in a post on Ursa Minor) would have carried the equinox into Virgo, where it is now (and where it will be until AD 2450). This seems to indicate that Libra as a scales must have existed when the equinox was well inside Libra, but there are many references to these stars as Chelae, the claws of the scorpion. First, as seen below, the stars of Libra work well as the claws of the scorpion, whereas with Libra as a scales, the scorpion’s claws seem a little pathetic. The (seriously cool) names of the stars could refer to this, with Zubeleschamale translating as “the northern claw” and Zubelelgenubi as “the southern claw”. This is contested in some sources (alright, I admit it – in an unsourced article on Wikipedia) in that the Arabic (zubānā) and Akkadian (zibanitu) words for “scorpion” and “scale” are the same. Life becomes more complicated with the constellation having either four claws or four scales, but Richard Allen’s Star Names: Their Lore and Meaning considers Zubelalgubi as a degenerate version of the name “Zubelelgenubi”, and Zubenelhakrabi (the scorpion’s claw) as belonging to g Scorpii, which was apparently due to a need to invent two new claws when the other ones became Libra.

.....Why were the scorpion’s claws made into the balance of Libra (assuming, of course, that this is what happened)? Sure, there would be pressure to have twelve constellations on the Zodiac, one per month, and the reason of having a balance at the point where day and night are balanced make sense, but I have another idea why an inanimate object was added to the Zodiac where it was …

Five minutes before the first sexual harassment lawsuit

.....Unfortunately, Libra is pretty boring as far as deep-sky objects are concerned. There are no open clusters or nebulae in Libra, and the galaxies and one globular cluster in Libra fall far from being easy to find. I’ll address these on my next pass. Zubenelgenubi is a fairly easy double star to split, with the companion star being dimmer, but not tremendously dimmer (magnitudes of 2.8 and 5.2), and about 4 minutes of arc apart, or about one-eighth the size of the Moon in the sky. I could split this double star with a pair of binoculars, so this represents an excellent opportunity to do the same, and take the first step towards learning how to observe and split double stars.

Ursa Minor, or Shakespeare Screws Up

Caesar: …” I am as constant as the northern star,
Of whose true-fix’d and resting quality
There is no fellow in the firmament.
The skies are painted with unnumber’d sparks,
They are all fire and every one doth shine,
But there’s but one in all doth hold his place”

Julius Caesar, Act III, scene I, lines 60-65

…..Shakespeare was a hack. More on this later.

…..A blog on Ursa Minor, the Little Dipper, is going to demand that I go pretty far afield to try and make this interesting because this is a pretty inconsequential constellation. The Little Dipper is probably the most famous constellation that almost no one can find. The constellation is always above the horizon literally until you reach South America as you go south, but except for the three brightest stars, including the Pole Star, Polaris, the rest of the constellation is so faint that it can be lost under pretty much any background light.

…..Ursa Minor, quite frankly, has its name write a check most of its stars can’t cash. The constellation would be quite ignorable if it were not for the star Polaris, and from Greek times to the Renaissance this constellation was sometimes referred to as “Cynosura” (what a translation to this word means is not known, but it probably has something to do with a dog) and sometimes that name only referred to the brightest star in the constellation, so for most of human history the general reaction to the constellation is, “The heck with it, just deal the bright, useful star.” (A reasonable question might also be “Why not just call it, like, “Polaris” or something that shows that since it’s by the Pole, and this brings us to one of Shakespeare’s mistakes. Again, more on this a little later.)

.....Polaris has its name because it is very, very close to the North Celestial Pole. To see why this is doubly lucky, let’s look for a moment at how the sky appears. Obvious statement of the day: the stars are all very, very far away. So far away that even as they move through space, a time traveler stepping from a clear night in first dynasty Egypt to tonight would only notice a shift in a handful of the stars with respect to each other, and even then only if that time traveler had some pretty good measuring tools. Because of this, it is useful to treat the sky as a dome, or as a globe that we see the inside of from the Earth. To map this, we use the Earth to help us. Consider the Earth as spinning inside this gigantic sphere; one thing that we could "see", projected against the heavens would be the sky appearing to turn as we spun beneath it. Projected on the sky, we could trace north and south poles above the Earth's north and south poles (called the North and South Celestial Poles, reasonably enough), and the Celestial Equator above the Earth's equator. The North Celestial Pole is less than half a degree of arc away from Polaris, so if you were to sit and watch the sky over the course of a night (an eminently worthy endeavor), the stars would appear to whirl around the sky, with only Polaris remaining still. (The South Celestial Pole has no stars of note anywhere near it.)

.....Even Polaris has gotten a reputation beyond its actual means. Because of the usefulness of Polaris, (perhaps) the true idea that Polaris will help you find where you are has led to the (false) idea that Polaris is inordinately easy to find. As I discussed in my post on the Big Dipper, and repeated in my map on the previous post, Polaris can be identified by using the two stars at the end of the bowl of the Big Dipper (which is relatively bright), but a surprisingly common misconception is that Polaris is the brightest star in the sky. How this came about, I certainly don't know. (Polaris is actually the 47th brightest star in the sky.) This has led one friend of mine to increase the "Don't Get No Respect" quotient for this constellation by arbitrarily and willfully defining the brightest visible star as "the North Star". (Hi, Trish!)

…..Besides the three brightest stars, the others are fourth, fourth, fourth, and fifth magnitude, this definition of brightness stretching back to the ancient Greeks when the astronomer Hipparchus divided the stars by their brightness, ranking the stars from “first rank” (the brightest) to “sixth rank” (the dimmest). The other stars that observers expect to see from the constellation figure are dim enough so that a hazy evening, a bright Moon, or the ubiquitous nearby Wal-Mart (in case you didn’t think that Wal-Mart was evil enough) will make these stars impossible to see. In seventh grade, when I got my first chance to study astronomy institutionally, one of our assignments was to sketch constellations we found in the sky. I saw a lot of students turn in the Little Dipper, but none of them got the right stars, a trend that I notice up to today. (A second thing is that I notice Wal-Mart is apparently in Microsoft’s spell-checker; Scorpius: No, Capricornus: No, Wal-Mart: yes – be afraid, be very afraid …)

.....Going back to that hypothetical time traveler, however, the sky as a whole would have shifted noticeably, because the Earth does not sedately simply rotate on its axis, that axis is tracing out a circle on the sky like a tremendous top, with a period of 26,000 years. This wobble is now pointing at Polaris, getting even closer as this century goes on, but in Julius Caesar's time, Polaris was more than ten degrees away from the pole (the "Secret Devil Sign", in memory of the recent death of Ronnie James Dio), making a definite loop during the night. Our time traveler would have seen Thuban (also on the map) as the North Star, and if you wait for about 13,000 years you will see Vega, in Lyra, as the pole star, and that truly is one of the brightest stars in the sky. This is Shakespeare's astronomy mistake in Julius Caesar.

….As far as anachronisms in Shakespeare go, though, this one is not the biggest, even in that play. In Act II, scene i, line 191, Brutus says “Peace! Count the clock.”, and in Act II, scene ii, lines 114-115, Caesar asks “What is’t o’clock?”, to which Brutus responds, “Caesar, ‘tis stricken eight.” Mechanical clocks in the time of Caesar (actually invented in the thirteenth century AD) would actually be less of an anachronism than, say, giving Macbeth Iron Man’s armor…

“Is this a transistor I see before me, the bipolar junction toward my hand?”

.....Oh sure, you might say that Shakespeare didn't know any better but he was able to come up with more appropriate way to discuss time earlier in the scene I just quoted, when Brutus says "I cannot, by the progress of the stars,/ Give guess how near to day." - lines 2-3.

…..Ursa Minor is an important place being filled by a rather boring occupant that is still bright enough to fulfill a useful purpose. (Like Al Gore - Zing!) Yes, I know that this would have been funnier ten years ago. Let me try this again ...

…..To sum up, Ursa Minor is a dim, dark, empty place with only a couple of bright points – kind of like Lower Michigan (Double Zing!)

The May Sky

.....There are many books and websites to help people who are good at astronomy become really good at astronomy, and many books and websites to (apparently) help people who live in the country where the sky gets what could actually considered to be dark (or at least where you don't have a direct line-of-sight to eight outdoor lights), but a lot of this can be counterproductive if you are just trying to start out, or if you just live where the sky is bright enough to hide a lot of the stars from you. Hopefully, this blog can be useful in both of these cases, but I realized that I might lose some of the benefits of talking about constellations if you aren't able to easily find those things in the first place, so I made a series of maps.

.....All of these maps show the sky as it is seen from the latitudes of the northern US about eleven PM (tonight), or about when the sky finally gets dark. The first map just shows the brightest stars, so while the constellation figures are missing stars, hopefully this stripped-down maps will help you find those constellations to begin with. (As you might see in just a moment here, sometimes star maps that have all visible stars can seem a lttle "busy", and be hard to follow. Also, in all maps the constellations in blue are the ones that have already been discussed in some depth in a blog post, and the constellations in red are the ones that I have yet to get to. Looks like a busy summer.)

.....Heck, even just giving these constellations might not be that helpful. After all, what I have is a representation of the sky as the inside of a giant bowl, flattened out and seen from the inside. In the spring and early summer, the Big Dipper can be used to find the North Star at the tail of Ursa Minor (the Little Dipper), Regulus, the brightest star in Leo, and following the arc of the stars of the handle leads to Acrturus, in Boötes, and then on to Spica, in Virgo.

.....With that (hopefully) as a means to help you find the constellations of the brighter stars, here is a map of the whole sky, helping you if you do live somewhere where the whole sky can be seen, and perhaps frusting you a little bit if you don't.

.....Note that the planets Mars and Saturn are both visible in our evenings! Both planets are about as bright as the star Spica, the brightest star in Virgo (and the end of the great arc from the Big Dipper's handle) Mars does not show much (to me, at least) beyond a disk in a telescope, but Saturn looks so phenomenal as to almost seem fake in even the smallest telescope. If you have anything, even an old department store cardboard 'scope, give Saturn a try!

.....As always, individual maps can be downloaded from this site.

Boötes-licious

.....Astronomy, by definition, is a study that encompasses the universe, and so there is are many different new things that a study of astronomy can bring you across. For example, I learned that the symbol on the second “o” in “Boötes” is not an umlaut, but a dieresis, indicating that both letters are to be pronounced. I have been presuming that this makes the pronunciation “Bu-u-tez”. I could well be wrong, but since the constellation is never going to get offended, who cares?

.....In legend, Boötes is a herdsman with his dogs (the constellation Canes Venatici) chasing the Great B ear (Ursa Major) forever around the pole, from the latitudes of the northern United States only getting six hours below the horizon a day to rest from the chase. A quick look at the star map will show that this legend is proof that the ancient Greeks had no knowledge of kites. If we were to remake the constellations today (a scheme which has been tried before, remind me to tell you about that sometime), Boötes would almost certainly be “the kite”.

.....The second constellation that I’m looking at in this post is the Northern Crown, Corona Borealis. If I may digress for just a moment, when I was much younger, carrying my telescope out to an extraneous plot of land behind our house, one of our neighbors asked me about what constellations were visible, and when I got to this one, he said,” No. That’s not it. I’ve seen that before and that’s not it!!!” (He didn’t shout, but he was speaking very definitively and I’ve learned that nothing is more definitive on the internet than using three exclamation points.) I realized pretty quickly that he was thinking about the northern lights, the *aurora* borealis, but I cannot remember if I tried to explain that, or just thought, “Whatever, old dude” (or whatever the early 80’s version of that was) and went on.

.....At least Corona Borealis looks kind of like a circlet of stars, but recreating Boötes would allow us to reimage the second constellation that we are looking at today, Corona Borealis away from being the Northern Crown into, say, the Kite-Eating Tree from Peanuts.



.....(I know that the kite appears larger than the tree; it’s foreshortening. The tree is in the background, waiting for the kite to slip up, drift away and get caught. If this story seems too grim for backyard astronomy, please reread the original myth.)

.....As far as telescopic objects in these constellations go, there are pretty slim pickings for the suburban astronomer. The North Galactic Pole is on this map, which means that these constellations are as far away from the pale band of the Milky Way in the sky as it is possible to get. There are a few galaxies in these two constellations, but all of them are close to the limit of visibility for a backyard telescope on the best of nights. I shall try and find each one, and then come back with an update, but I really would not be expecting very much.


.....While Boötes and Corona Borealis don't have any bright deep-sky objects, they do have a couple of bright double stars that small telescopes can reach. Most stars aren't like our Sun, traveling alone through space (yes, I like the planets, but they are very tiny things compared to a star), but travel in packs of two, three, or even more. The vast majority of these stars are so far away that we can't even see them as individual stars, but some of the closer ones can be "split", as it were, in a small telescope. The two things that I look for when looking for interesting double stars are that the stars are of close to the same brightness (so one does not overwhelm the other) and are far enough apart againts the sky to be split. It also helps if the pair is bright enough to be found easily in the sky. The brightest and best in these constellations is Izar (epsilon Boötis). The two stars have magnitudes of 2.5 (bright enough to see from suburbia) and 4.9 (bright enough to be seen from some nice, quiet farmland), but they are quite close together, with a separation of 2.8 seconds of arc, or about 1/600th the size of the full Moon. (This is a useful measure for me, in that my 8" telescope, at low power, can just barely fit the whole Moon in the field of view.) You will need to use a higher magnification eyepiece to see this pair as two stars.


.....If you can find Alkalurops (Mu Boötis), that will be much easier, and the two stars will be distinct as separate stars under even what is typically the lowest magnification lens for a given telescope, 1.8 minutes of arc (1/33rd of a degree, or about 1/16 the size of the full Moon) with stars of magnitudes 4.3 (can be seen on a good night, maybe not actually in a city) and 7.0 (invisible without the telescope/binoculars. I'll give you more once I have a chance to go hunting myself, until then, please don't hestitate to let me know what you like to see (or what you'd like my help to know about something you're seeing, in other words).

Not Dead!

I just wanted to announce that this blog is not dead! After the demands of the school year choked it back last fall, this summer will see many, many (okay, maybe just "many") posts, with hopefully a large backlog to carry me through the winter. I will be focusing especially on people who might have gotten a telescope as a gift who is now taking it out as the nights start to get warmer ...