AMATEUR ASTRONOMY:

PERSEIDS TONIGHT:

Tonight will be the best time for viewing the annual Perseid meteor shower (see diagram above). The peak will arrive at approximately 1:00 Universal Time. That is at about 7 PM CDT here in Winnipeg. To work out what that is in your own time zone see the Time and Date website. That also also gives useful information about such things as sunset and moonset. Tonight the very thin waxing crescent Moon will set early and provide little interference with meteor viewing.

The weather report from the Weather Network predicts overcast skies tonight here in Winnipeg. There is, however, a much better sight for forecasts of sky conditions. The Clear Dark Sky site also gives viewing conditions for the entire North American continent if you plug your location in. It lists not just cloud cover but other conditions that affect visibility. According to that sight there will be a window of opportunity here in Winnipeg for viewing between 9PM and midnight. That is exactly what it looks like to me observing the sky shortly before sunset. The best time for viewing meteor showers is usually after midnight, but you take what you can get. If tonight fails for you don't panic. While predictions for the Perseids this year say anywhere from 50 to 80 meteors per hour you will be able to see a diminishing number in the next few nights.

Molly has blogged extensively about the Perseids in previous years. For 2009 see here. In 2008 there was this, this and this. For 2007 see this and this. So, for all sorts of fun facts about this event and meteor showers in general consult these previous posts.

Here are a few other fun sites where you can read about the Perseids.

Shadow and Substance (an animation of the shower)

Cosmic Log

Sky and Telescope

Happy viewing.

AMATEUR ASTRONOMY:

THE PERSEIDS RETURN:

Tomorrow evening (or for that matter just before dawn today- August 12) will be the optimum time for viewing what is usually the most spectacular meteor shower of the year- the Perseids. The estimated time of the peak (these things are never exact) is at about 15:00 Universal Time tomorrow afternoon. This translates into a Winnipeg time of 10:00 am. Fear not and do not despair. The Perseid meteor shower is actually quite a long drawn out affair,and an excess of meteors may be observed from July 23 to August 22. The Winnipeg branch of the Royal Astronomical Society of Canada actually plans to hold their Perseid viewing gathering next Sunday, August 15, out at Bird's Hill Park, just northeast of the city. The view of meteors is, of course, best seen at a dark location outside of a city, such as Bird's Hill Park. Just as a fyi, however, the Astronomical Society will apparently have their telescopes out, for public education, at the Italian Pavilion down on Wilkes Ave. during this week of Folklorama. Telescopes are of no use for viewing meteors, but those interested can gain an appreciation of the hobby from members who will be present there. The occasion, Italy wise, is the 400th anniversary of Galileo's telescope. Would that we could celebrate a centenary of the end of the Congregation for the Doctrine of the Faith (the Holy Inquisition) who condemned Galileo, but that institution still exists today.

Sunset tomorrow here in Winnipeg is at 8:52 pm, and Moonrise (the Moon interferes with good viewing of meteors) is at 10:52 pm. For those in locations outside of the Central Time Zone please consult the Time and Date website to convert the time of the Perseid peak (and Sunset and Moonrise) to your local time. According to said website the weather conditions here in Winnipeg for tomorrow evening will be "partially cloudy". The Environment Canada site predicts "a few clouds for tomorrow evening. One of the best sites, the Clear Dark Sky site, says that the sky will be basically clear until Midnight, with clouds in the wee hours of Thursday, but clearing about 4:00am. The Clear Dark Sky site is actually one of the best sites to consult because it contains far more parameters than just cloud cover. It is also the site for readers anywhere on the North American continent because it will give viewing conditions for hundreds of sites elsewhere on this continent. So...if you don't live in the centre of the universe known as Winnipeg consult this site to see whether your viewing conditions for the Perseids will be good, bad or indifferent.

By the way, Molly has blogged extensively on the Perseid meteor shower before. If I fail to repost items from previous years (which might happen because of my schedule) try searching "Perseids" on this blog for much more information of this event.

AMATEUR ASTRONOMY:

THE PERSEIDS ARE HERE TONIGHT- BUT WE SURE WON'T SEE THEM IN WINNIPEG:

Yes, the Perseid meteor shower will be peaking later this evening in the early hours before dawn tomorrow, but we sure won't be able to see them here in Winnipeg. Speaking of showers it's been raining cats and dogs since last night, and the weather reports (both Environment Canada and the Clear Dark Sky organization) say that this will persist until shortly before dawn on Wednesday morning. Maybe you'll still be able to catch a few meteors on that day, but at least for Winnipeg this years Perseids will be a "wash-out". The viewing conditions including cloud cover, transparency, visibility, etc. can be seen for Winnipeg by clicking the strange looking long rectangle divided into boxes at the bottom of our links section.

For people living elsewhere on the North American continent, however, conditions may be far better especially if you live on the west coast where the peak occurs when it is still dark. The Clear Dark Sky link reports conditions for 3,497 different locations in North America, from Mexico and the Bahamas in the south to Alaska, Yukon, NWT and Nunavut in the north. It's a great site and Molly encourages visitors to it. So, may you have better luck than we do here in Winnipeg.

AMATEUR ASTRONOMY:

THE PERSEIDS ARE HERE-TONIGHT!:

Well, not exactly, more like the wee hours of tomorrow, August 12. But still "this night" has some meaning. Here are a few relevant times of other events that may affect your viewing from the Time and Date website. These times are for here in Winnipeg in the Central Time Zone. If you live elsewhere consult the above website for your local times.

Sunset today, August 11........................8:53 PM

Sunrise tomorrow, August 12...............6:15 AM

Moonrise tonight, August 11.................6:12 PM

Moonset tomorrow, August 12.............1:19 PM

....................................

As previously mentioned on this blog the peak of the Perseids will fall between 11:30 and 14:00 UT. This translates as 6:30 am and 9:00 am here in Winnipeg so observers in this province will miss the peak of the shower. Viewing in the early pre-dawn hours, however, may still be rewarding. The further west you go the better the timing, and people on the west coast should have a good show.

..............................

THE RADIANT

The diagram above shows the "radiant" for the Perseid meteor shower. The radiant in a meteor shower is the place in the sky where the meteors appear to be coming from if you trace back their paths. As you can see above the radiant of the "Perseids" is actually between Perseus and the constellation Cassiopeia. Still somewhat closer to Perseus however. See if you can determine the radiants of the meteors you see tonight.

AMATEUR ASTRONOMY:

THE PERSEIDS ARE COMING- WHAT IS A METEOR SHOWER ?:

As mentioned previously the Perseid meteor shower will peak this coming Tuesday, August 12th between 11:30 to 14:00 hours UT. That would be 6:30 to 9:00 here in the central time zone in Winnipeg. To get an idea of the time in your locality see the Time And Date website. This website also gives the times of Moonset and Moonrise, important this year as the light from a waxing gibbous Moon will reduce meteor viewing considerably. The good news is that the Moon will be setting shortly after midnight. The bad news for European and eastern North American viewers is the time of peak. In Europe this will occur during daylight hours, and even in North America the Sun will be rising during at least part of the peak. Still, any meteors seen in the early predawn hours may turn out to be spectacular "Earth grazers".

METEOR SHOWER...WHAZZAT ?:
A "meteor shower", also known as a "meteor storm" or a "meteor outburst" is when there is an unusually high number of meteors in the sky and when these events can be traced back via an imaginary line to a point of common origin in the sky called the radiant.

Meteors happen when the Earth encounters bits of cosmic debris in its orbit around the Sun. Like litter in a campground such debris is ubiquitous in space, and there is always a background of sporadic meteors that occur randomly. Some neighbourhoods, however, are filthier than others. Throughout the year the Earth periodically passes through particularly concentrated trails of material. These have usually been traced to the residue of passing comets, and their position in the orbital plane means that they regularly appear in the same place in the sky at the same time of year.

When the cosmic debris is just hanging around orbiting the Sun (maybe playing cards, smoking cigarettes and, like a Spanish policeman, doing as little as is possible) it is known as a meteoroid . It is only when the Earth catches up to this non-event that things begin to get interesting. As the Earth and the space particle collide the debris becomes a visible meteor . These pass into the Earth's atmosphere at anywhere from 14 to 71 kilometers per second. Most meteors become visible at about 60 kilometers up. They are heated to over 1,700 degrees centigrade, begin to glow from the heat and are usually consumed by the heat as they enter the inner atmosphere. This heating is not caused by "friction" but rather by something called "ram pressure". As the meteor plunges into the atmosphere it compresses the air in front of it, thus heating it up. The heat of this compressed air simple diffuses to the meteor itself. In other words the heat comes from a push rather than a rub.

Should the meteor actually make it through the atmosphere and strike the Earth it is called a meteorite. There are two basic kinds of meteorites. Iron meteorites are made up of about 91% iron. Stony meteorites contain a higher proportion of other elements such as magnesium and especially silicon and oxygen in the form of silicon dioxide- good old sand.

(Hey, Molly could make a song out of this...
"Let's build sand castles in the sky
Let them loose to see if they can fly")

Some meteors explode before they evaporate or strike the Earth. The result is commonly called a fireball, and its sound can be heard dozens of miles away. Iron meteors are more stable than rocky ones. Slow meteors are less likely to explode than fast ones. Meteors arriving at an acute angle to the Earth are subjected to less stress than those that come in at an oblique angle. Yet...even a slow travelling iron meteor that falls from near the zenith has a chance of exploding and creating a fireball.



There is reportedly another sound produced by meteors that is poorly understood. These events are referred to as electrophonic meteors which seem to produce a sound even though it is physically impossible for any sound to travel from the height of the meteor. See 'Electrophonic Meteors' and 'Listening to the Leonids'. The theory is that this sound, variously described as "sizzling" or a "snap,crackle,pop" is produced when electromagnetic radiation in the VLF range is converted into sound energy near the ground.



When a meteor strikes the ground it produces a crater anywhere from 12 to 20 times its own size. Smaller impacts produce simple bowls. When larger objects strike terrestrial rebound creates a central peak along with a rim that is often "terraced" as the ground subsides after the initial impact. The largest impacts of all create multiple inner peaks due to the creation of several rebounds.



The largest impact in recorded history occurred on June 30th, 1908 when an object struck in Siberia. This has become known as the Tunguska event. This object flattened more than 800 square miles of trees. The cause of this explosion has been disputed, but the present consensus is that it was an exploding meteor. An Italian research team has recently obtained results that are suggestive of a remnant of part of this meteorite at the bottom of Lake Cheko about 5 miles northwest of the epicentre of Tunguska. See http://www.blackwellpublishing.com/journal.asp?ref=0954-4879&site=1 for the article 'A Possible Impact Crater for the 1908 Tunguska Event'.



Every year many meteorite strikes are reported across the planet. The first structure to be proven as being due to a meteorite impact is the Meteor Crater of Arizona. This crater is 600 feet deep, about a mile across, and its rim rises 150 feet above the surrounding ground. The meteorite that produced this crater impacted sometime between 20,000 and 50,000 years ago. The largest meteorite ever recovered in the USA hit ground in southern Nebraska in 1848. Observers reported that the fireball, which occurred in the afternoon, was "brighter than the Sun" This item, weighing 2,360 pounds was found buried 10 feet deep in a wheat field. Of course the Russians always did it first and better, as anyone who has listened to Chekov in old Star Trek shows can tell you. In 1947 the Russian Sikhote-Alin meteorite created more than 100 small craters some 20 meters across. Eat them apples American imperialists.



There is even a recent controversial theory that the die-off of mega fauna in North America at the end of the last ice age was not due to over hunting by recently arrived paleo-indians-the accepted theory- but rather due to localized climatic change because of an impact event. Maybe yes, maybe no.



For those interested in learning more about meteors in general look to the following sites:
The International Meteor Organization
The American Meteor Society
Meteor Showers Online

AMATEUR ASTRONOMY:

THE PERSEIDS ARE COMING- THE CONSTELLATION PERSEUS:

THE CONSTELLATION PERSEUS:
In most years the Perseid meteor shower is the most spectacular of the many meteor showers observable. There are usually between 50 and 80 meteors per hour on the night of its peak which this year falls in the early hours of Tuesday, August 12. Here's a little introduction to the constellation Perseus from which these meteors seem to originate.
FINDING PERSEUS:
The exact location of any constellation varies, of course, with the season and the time of night. Perseus, however, is a circumpolar constellation, and one can locate it easily by reference to other northern sky landmarks. At this time of year it can be found in the northeast;the later at night the higher it will be seen. Draw a line from the two "pointer stars" of the Big Dipper, Dubhe and Merak, across the Polaris the North Star. Continue the line onward past the inverted pentagon of Cepheus to the "W" of Cassiopeia. Look down towards the horizon, and you'll find the "K" of Perseus.
If this is not helpful there are a number of star maps online that can help you in locating any of the constellations. See:
Your Sky
The Dome of the Sky
and for a selection of many sky maps, some free and some not, go to Planetarium Software.

THE STARS OF PERSEUS:
The diagram to the left above illustrates the major stars of Perseus. Molly has always seen Perseus as the "K" shape described by most commentators. Others have described it as a "fleur de lis", but I have consistently been unable to see such a thing in this constellation. Perseus contains four named stars. The brightest, alpha-Per, is usually called Mirfak, from the Arabic for elbow, and sometimes Algenib, from the Arabic for "the side" (though other stars also bear this name). It is a white supergiant of 1.8 apparent magnitude and is about 620 light years (lys) away. Mirfak is 62 times the size of our sun and 5,000 times as bright.

The most famous star in Perseus is beta-Per, Algol the demon star. The name comes from the Arabic "Alghul" which means "the ghoul" or "the demon". It is often referred to as "the head of the demon" because it is supposed to represent the head of Medusa (see 'The Legend of Perseus' later in this blog). This star is the classic eclipsing binary variable star. In these systems each member of the pair periodically eclipses the other. Algol consists of a blue main sequence star and a yellow-white subgiant. This system usually shines with a magnitude of 2.1, but every 2.87 days it dims to magnitude 3.4 for 10 hours as the subgiant passes in front of the other star. this system is 105 light years away.

Xi-Per is called Menkib from the Arabic for "shoulder". It is a blue star of magnitude 4 with a distance of 150 light years. Omicron-Per is called Atik from the Arabic for "collarbone". It is a blue giant of magnitude 3.8 and is 1,000 light years away.

Epsilon-Per (to the horizon from Mirfak and to the west of Algol) is the main radiant of the Perseid meteor showers. Note that the first diagram above is incorrect in this matter, though the casual observer could hardly tell the difference. There are also, however, other radiants within the constellation, and so not all the meteors seen will be traceable back to the neighbourhood of epsilon-Per. Epsilon-Per is a binary system about 130 lys from Earth. the brighter component is a blue main sequence star of magnitude 2.9, and the dimmer is only of the 8th magnitude. Stars dimmer than magnitude 6 are invisible to the naked eye.

AMATEUR ASTRONOMY:

THE PERSEIDS ARE COMING-WHEN WILL THEY BE HERE?:

The short and snappy answer is that they're already here. Before you panic you should know that you still have plenty of time until the peak in the early hours of August 12. The Perseids actually extend from July 17th to August 24, growing in frequency towards the peak and declining thereafter.

The predicted peak will be at 11:30 UT. That's 6:30 am local time here in Winnipeg in the Central Time zone. To find out what time this is in your own local time zone consult the Time and Date website. This website also has the times of Moonrise and Moonset, an important thing as there will be a waxing gibbous Moon in the sky that could interfere with viewing. The Moon,however, will be setting near midnight, long before the time of best viewing. The constellation Perseus will be above the horizon through almost all of the night, rising higher as time goes on. This year there may be secondary and even tertiary peaks (at 16:40 UT and 21:30 UT, August 12. ), but they won't be visible from North America. Predictions are that the best viewing will be around the Pacific, including the west coast of North America and east Asia.

For more about the Perseids see the International Meteor Organization , especially their calender section.

AMATEUR ASTRONOMY:

THE PERSEIDS ARE COMING-THE 'TEARS OF ST. LAWRENCE':

As Molly has mentioned before the Perseid meteor shower will peak this year on August 12, 10 days from now. The legend of Perseus belongs to antiquity-and Molly hopes to deal with them in good time-, but there are also Christian legends associated with this event. The Perseids are often referred to as "the tears of St. Lawrence". How did this come about ?

WHO WAS ST LAWRENCE ?

St. Lawrence (c 225-258) was reputedly martyred under the Emperor Valerian in 258 CE. He was supposedly a native of Osca (present day Huesca) in Hispania. Under Pope Sixtus II he was appointed a deacon and placed charge of the Church treasury and archives in Rome. because of this he is considered the patron saint of librarians and archivists. The Emperor's agents began to round up Christians in the city, with special interest paid to those who belonged to the upper classes in hopes of the confiscation of their property. These rather mercenary motives on the part of the Imperial administration are part and parcel of one part of the legend of St. Lawrence, that Pope Sixtus, who was executed before he was, instructed him to divide the Church's treasury amongst the poor. when he was brought before Valerian and told to produce the Church's treasury he brought forth the poor and told the Emperor that "these are the treasures of the Church".

Sounds pretty admirable does it not ? But read on. This little act of theatrics would seem to be annoying enough, but Lawrence committed a much greater offense. Remember what the main purpose of this whole affair was- to get at the property of rich people who were closet Christians. Well no way was Lawrence, as the record keeper of the Church, going to betray their names. Stop and think for a minute. You can haul the poor before the authorities (one wonders if many of them were even aware of the danger they were in), but perish forbid that you should rat on the rich.

This went over like a lead balloon. According to the legend Lawrence (Lorenzo in Italian) was sentenced to death by slow roasting over an outdoor grill. From this part of the story comes his patronage of cooks and tanners. according to the story he said to Valerian who was observing the execution, "I am already roasted on one side, and, if thou wouldst have me well cooked, it's time to turn me on the other". For some inexplicable reason Lawrence never became the patron saint of snarky comments.

There is lots more to the legend, including his miracles, but little of it is verifiable. The accounts of his life, work and death were not set down for over a century after his birth, and, according to the Catholic Encyclopedia entry on him little is known besides the bare fact of his existence, his martyrdom, place of execution and date of burial. Most of the details of the legend are actually almost certainly fanciful. To read the full story in all its medieval embellishment go to 'The Life of St. Lawrence' in Jacobus de Voragine's 'The Golden Legend'.

LAWRENCE AND THE HOLY GRAIL

Before leaving the legendary, however, we should look at the legendary connection of Lawrence with the "Holy Grail". This cup that was supposed to have been used at the Last Supper had been in use for the saying of Papal masses for some time when Pope Sixtus II was executed. This two handled cup was given by Lawrence to a legionnaire from his home town of Osca who delivered it to Lawrence's parents. There was once a fresco in the Basilica of San Lorenzo in Rome depicting Lawrence giving the cup to said soldier, but it was destroyed by Allied bombardment in WW 2 in July of 1943.

In Spain the 'Santo Caliz' was placed in the new church in Huesca by Bishop Vicentius in 553. In 711 the Holy Grail was taken north in the face of the Muslim invasion of Spain by Bishop Acisclo to San Pedro de Siresa. From there it travelled to the Cathedral of Jaca, and finally in 1063 to the monastery of San Juan de la Peña where it was guarded in a cave by the Templars. In 1399 King martin V of Aragon moved the grail to the royal palace in Zaragoza. In return he donated a gold replica of the cup to the monastery. In 1424 King Alfonso V moved it to his palace in Valencia, and finally in 1437 Alfonso's brother, Don Juan of Navarre, placed the grail in the Cathedral of Valencia where it remains to this day. It has left there only twice in the subsequent centuries, once during the War of Independence (1809-1813) against Napoleon and during the Spanish Civil War (1936-1939) when it was hidden in private homes until the victory of the fascists. In 1982 Ope John Paul II became the first Pope in over 1700 years to celebrate Mass using the Holy Grail.

One would never gather, in the accounts of pop-mysticism current today, that an actual 'Holy Grail' has a public presence. In a more gruesome fashion there is another relic connected to the cult of this saint. The Vatican holds a reliquary that supposedly contains his burnt head, and it is present for the veneration of the faithful.

THE TEARS OF ST LAWRENCE AND CANADA

A legend grew up that on the night of Lawrence's execution the sky was brightly lit by the meteors of the Perseid Meteor Shower. True or not the shower came to be traditionally known as the 'Tears of St. Lawrence'. On August 10, the feast day of St. Lawrence explorer Jacques Cartier was encamped on the north shore of what is now known as the Gulf of St. Lawrence during his first voyage to the New World. In honour of the Saint he named the body of water after him. The St. Lawrence River was named "the great River of Hochelaga" by Cartier, but was later renamed the St. Lawrence River by Samuel de Champlain. Cartier began European contact with the local natives in a fashion that became a Canadian standard in forthcoming centuries- he kidnapped the two sons of Chief Donnacona. Something for the Saint to actually cry about perhaps.

AMATEUR ASTRONOMY:

THE PERSEIDS ARE COMING:

While often not the "best" meteor shower of the year the Perseids occur at a time of year-early August- that is comfortable (mosquitoes excluded) for viewing in Canada. This year the Perseids will peak on August 12th in the constellation Perseus, even though the rate of meteors has been increasing since July 17th. Stay tuned to Molly's Blog for more news about this astronomical event.

AURIGID METEOR SHOWER REPORTS:

The online space news site Space.Com has published a story written by Peter Jenniskens of the airborne Multi-Instrument Aircraft Campaign. This event was witnessed by only twp observers in 1994 and one in 1986. This year far more people, perhaps thousands, managed to catch the shower due to the predictions of the time based on modelling by Jenniskens' team. Observers in the eastern USA, Brazil and Europe, while unable to directly see the meteors, detected them by listening for distant radio signals. The peak rate at 4:04 PDT detected by the airborne observers was about 100/hour, and the airborne crew saw around 120 meteors each. This meant that they outshone the August Perseids, even if only for a very brief time (see blogs on this post for August and September for more about both the Perseids and the Aurigids). Further details on the results can be found at the above link and also at http://aurigid.seti.org/ . The latter link also gives details on what was seen by ground observers who lived where the shower was visible that night.

LAST CALL FOR THE PERSEIDS:

The intensity of the Perseid meteor shower will fall off rapidly in the next few days. Tonight, however, you may still be able to catch more than a few meteors in a dark location. The skies here in Winnipeg have actually cleared, and viewing conditions may be quite good- a nice wind and few mosquitoes. Try and have a second go at it.

Monday/Tuesday//// August 13th/14th

A Few Interesting Matters From Space.Com (http://www.space.com ).
This site is a gathering point for all things astronomical, cosmological and astronautical. What follows is a few articles that I found interesting in the last few posts. You can sign up for regular updates from this site. Good to explore.
1)Dirty Son-Of-A-Bitch division.
The annual Perseid meteor shower is due to peak tomorrow (August 12th). Best viewing is, of course, as with any meteor shower in the early morning of the 13th because of the angle of rotation. In the early morning hours the meteors are "oncoming" rather than playing "catch-up" But SDC says that a lot of this year's event will be obscured by an almost full moon (actual date August 9th). Posted on SDC on August 4th/2006.
2)Posted on August 7th/2006 the article 'The Universe Might Be Bigger and Older than Expected" discusses that a recent study of the distance to the 'Triangulum Galaxy', one of several "cosmological landmarks" suggests that the Hubble Constant is actually about 15% smaller than the accepted value. These results will be published in an upcoming issue of 'Astronomical Journal'. This would put the age of the universe at about 15.8 billion years rather than the commonly accepted value of 13.7 years. The study depends upon calculations of the 'true luminosities' of binary stars, just as calculations of true luminosity are often made via Cepheid variables. The new findings, of course, have still to be confirmed, though I must admit that the younger age implied by the previous estimates of the Hubble constant have always bothered me.
3)Finally, an article posted on August 8th/2006 entitled 'Organic Molecules Found in Diverse Space Places' (published in a recent edition of 'Astrophysical Journal') spoke about finding 8 organic molecules in as diverse places as nebulae and interstellar voids. The total # of biologically-relevant molecules now found in space is about 141, including even benzene (see the famous story of how the discovery of benzene was related to a dream about the self devouring serpent 'Tiamat'). All of this is connected to the origin of life. Is life indeed the dream of Tiamat ?