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The Sky This Month - September 2017

Thu, 2017-08-31 21:52

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

Mon, 2017-07-31 18:57

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