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The Sky This Month - September 2017

Late Summer Observing

By now you have probably heard about the close approach of asteroid 3122 Florence on September 1. During the first few nights of September, you will have the opportunity for follow asteroid 3122 Florence on its northern trek. The asteroid is named in honour of Florence Nightingale – the founder of modern nursing in the early 1900’s. This 4.4 km long mountain is a member of the Athens asteroids that orbits the Sun every 859 days and range in distance from 1.0 to 2.5 astronomical units from the Sun. At 8:06 a.m. EDT on Sept 1 it will be some 18 times the distance between the Earth and the Moon and will not come this close until the year 2500. 

Estimated to be 9th magnitude, backyard telescopes and binoculars should be able to spot Florence as it races at 14 km/sec through Capricorn Aquarius and Delphinius. Photos will confirm motion after a few minutes. Ground based radar images may resolve detail some 10 metres across.

From a dark location – away from stray lights, the Milky Way is seen beaming overhead. Cooler nights give way to the hot hazy conditions of this past summer. With less atmosphere to contend with this would be a great opportunity to image objects in Cygnus such as NGC 6888 aka the Crescent Nebula. This emission nebula is located 5,000 light years away and is listed at magnitude 7.4 and measures 18 by 12 degrees. Then there is the North American and Pelican nebulas located close the Swan’s tail - the star Deneb.  

At the southern end of the Milky Way we see the ringed planet Saturn dip below the south-west horizon at midnight local time at the beginning of the month with the constellation Sagittarius following an hour later.

September 15 will mark the end of the highly successful 20 year Cassini mission. Launch in October 1997, Cassini took 7 years to reach the ringed planet and for the next 13 years studied Saturn and mysterious moon system. On its last day of work, Cassini will receive its last instructions to intentionally dive into Saturn’s atmosphere, never be heard again. This eliminates the chance of crashing into a moon and contaminating it for future missions. 

As the night goes on into the wee hours of the morning and the temperature drops to single digits, the Hyades cluster which outlines the horns of Taurus the Bull and Pleiades clusters (the bull’s heart) are well up in the east by 1 a.m. As if these two clusters still do not remind you of winter, Orion the Hunter is up by 4 a.m.

Starting from the 18th, you have a two week period to look for the zodiacal light in the east before dawn. Here we see the leftover interstellar dust of the solar system lit by sunlight. Try using a wide angle lens on your camera and image this impressive sight. It reaches about 40 degrees in height.

This month’s full Corn Moon occurs on the 7th with new moon on 20th lunation (1172).

Until next month, clear skies everyone.

Gary Boyle

Twitter: @astroeducator

Author: Gary BoyleeNews date: Thursday, August 31, 2017Category: Northern SkiesFile:  2017 - 09 chart 1.jpgTweet::  Pages

The Sky This Month - August 2017

The Long Awaited Eclipse

Astronomers across North America have been preparing for the long awaited total solar eclipse and the time has come. On August 21 the 115 kilometre wide path approaches the main land in Oregon. Over time, it will move eastward until it heads out the Atlantic Ocean off the South Carolina coast. In all, the path cuts through fourteen states with millions of people seeing the Sun fully covered for a maximum of two minutes and forty seconds. This allows the unique opportunity to glimpse the red prominences along the rim of the Sun as well as the illusive corona without protective filters. The corona is the outer part of the Sun's atmosphere and only visible during totality. Temperatures exceed one million degrees in this layer but the solar surface is a cooler 5,600 degrees. For the tens of millions of people living north and south of the line, they will witness a partial phase including Canada. The big winner will be Victoria, BC where the eclipse begins at 9:08 a.m. PDT with 91% coverage at its greatest point. On the other side of the country St. John's, NL begins at 3:29 p.m. NDT with only 43% coverage. 

Precautions must be taken anytime you stare at the Sun. Never take chances with your eyes. There are various filters on the market to enjoy this wonderful event in safety. The RASC and other sites sell eclipse veiwers or eclipse glasses which are popular at public gatherings. You can also purchase Baader sheet film at various telescope locations. These are ideal to place in front of telescopes, binoculars and camera lenses. Never try to make and use homemade alternatives as eye damage can occur. Even pointing an unfiltered DSLR or point and shoot cameras can damage the sensitive chip inside. You can also damage your smart phone camera it pointed directly at the Sun. 

A great project with the family is to construct a pin hole camera. With the image of the eclipse projected on the back of the shoe box, this illuminates the dangers of looking directly at the Sun. Trees can also make great pin hole cameras with hundreds of projections being cast on the ground. Interlocking fingers also works and practically anything with tiny holes. Welder glass can also be used. Be sure to only purchase #14 grade glass used for arc welding.  Various RASC Centres will be hosting eclipse viewing parties open to the public. Check online for your closest centre or astronomy club.

 There should be a few good sites streaming live on the internet. The next total solar eclipse will take place on April 8, 2024 when it crosses Mexico, the USA and Canada. Since its creation some 4.5 billion years ago, the Moon is slowly spiralling away from Earth at a rate of four centimetres or the width of a golf ball per year. The last total solar eclipse will occur some 600 million years from now.

 A mere nine nights before the eclipse, the Perseid meteor shower will grace out skies. The Perseids are produce from the dusty debris from Comet Swift-Tuttle that last rounded the Sun in 1992 in its 133 year orbit. As Earth orbits the Sun, we encounter this clouds of particles the same time each year. Considered as the best meteor shower of the year, the Perseids can produce about 100 meteors per hour with a few brilliant fireballs. The 2016 shower had an outburst of 160 per hour. Unfortunately the 71% illuminated waning gibbous moon will rise around 11 p.m. local time will cast a glow in the sky and reduce the hourly rate. The good news is this is a weekend event.

The planet Jupiter is sinking lower in the west as the weeks march on. Venus still lights up the morning sky and is located just above Orion's club. This also means the Pleiades are up by 1 a.m. local time. Saturn is visible most of the night by is below the horizon before 2 a.m. local time on August 1. The full Sturgeon Moon will be on August 7.

Until next month, clear skies everyone.

Gary Boyle

Twitter: @astroeducator

Author: Gary BoyleeNews date: Monday, July 31, 2017Category: Northern SkiesFile:  image 1 - eclipse path.jpg Saturn.jpgTweet::  Pages

The Sky This Month - June 2017

Ursa Major

The great bear commonly known as the Big Dipper is a circumpolar constellation that never sets from Canadian locations. Its familiar four stars of the bowl and three stars of its handle are bright enough to be recognized at first glance. At this time of year, the Big Dipper is directly overhead and well placed to observe its celestial treasures.

Ursa Major is a great reference marker and jumping point to other constellations such as finding the North Star. To do this, draw an imaginary line through the two front stars from Merak and up through Dubhe located 79 light years and 123 years respectively. Now continue this same line until it brings you to Polaris – the pole star. This 432 light year F7 yellow supergiant star has a very close companion.

One of the best visual double stars in the sky belongs to the middle star in the handle called Alcor and Mizar (the rider and the horse). Splitting them with the naked eye is a good indicator of sky condition. With a telescope, you can now see how Mizar itself is a close double star.

Amongst the handful of Messier objects that reside in and near Ursa Major, the Owl Nebula is a challenge to see visually. At 2,600 light years from us, M97 is a faint planetary nebula that spans two light years in width. The Owl is nicely positioned close to the bowl star Merak. Not too far is the 10th magnitude galaxy M108. Located 45 million light years, the galaxy also called the Surfboard Galaxy, appears cigar shaped. Separated by one and a half times the width of the full moon both make a striking contrast.

Moving to the other bowl star named Phecda located 83 light years we find the galaxy M109. At a distance of only 38 arc seconds you will have to keep the bright magnitude 2.4 star out of the field of view to catch the much fainter magnitude 9.8 galaxy. There are numerous other galaxies in and below the bowl to locate and enjoy.

The planet Jupiter is high in the sky for most of the night and sets at 2:45 a.m. eastern time at the beginning of the month. There are three double transits of the Jovian moons visible this month on the 2, 4 and 20. Check page 234 of the Observer’s Handbook 2017 for details. Times are listed in Universal Time so remember to convert to your time zone. The king of planets becomes stationary on the 5th.

Saturn is nestled in the Milky Way with a wonderful back ground of stars. It rises in the south east by 10 p.m. It is at opposition on the 15 and sets in the west at sunrise. Venus rules the morning sky at is at its greatest western elongation on the 3rd at 46 degrees from the Sun. On the morning of the 3rd, the planet Uranus will be 1.8 degrees north of Venus. A great photo opportunity with the pairing of the crescent moon comes on the morning of 20 and 21.

On May 14, a magnitude 12.6 supernova was discovered in NGC 6946. The face on galaxy is located in Cygnus at an estimated 22 million light years away and is listed at magnitude 9.6. This galaxy is a hot spot for supernova activity as this latest discovery makes it the tenth in the past 100 years.

The summer solstice occurs on June 21 at 12:24 a.m. EDT. The full Strawberry Moon occurs on June 9 at 9:10 a.m. EDT with new moon (lunation 1169) on the 23rd.

Until next month, clear skies everyone.

Gary Boyle

Twitter: @astroeducator

Author: Gary BoyleeNews date: Thursday, June 1, 2017Category: Northern SkiesFile:  2017 - 06 chart 1.png 2017 - 06 chart 2.pngTweet::  Pages