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The Sky This Month - September 2018

Pegasus The Winged Horse

The constellation Pegasus is easily identified by its large square of stars. When rising in the east, its takes on the appearance of a giant baseball diamond. With 1,121 square degrees of sky Pegasus ranks 7th in overall size. It is also one of the original constellations listed by the astronomer Ptolemy back in the 2nd century.

On our imaginary baseball diamond, the third base star name Alpheratz is also deemed alpha Andromeda. This is a (B8) subgiant blue star with a surface temperature of 13,000 K or a little more than twice that of the Sun. Located 97 ly away, Alpheratz has a luminosity about 200 times that of the Sun.

Located in these two constellations are a few great targets at should be on your observing list. Towards the northern portion of Pegasus there is NGC 7331. Known as the Deer Lick Galaxy, this impressive spiral is located 48 million ly from us and shows many areas of young blue star clusters as well as red emission nebulas. This 9.3 X 3.8 arc second galaxy glows at magnitude 9.4.

Located off to the side of this lovely spiral are a few very remote galaxies. NGC 7335, 7336, 7337, 7340 are located 310, 430, 320 and 310 million light years respectively from us. Move south to the illusive group of galaxies known as Stephan’s Quintet. Ranging from magnitude 13.9 to 16.4, these reside in the range of 290 million ly except NGC 7320 which is a foreground galaxy and not part of the group.

Now move your telescope to the closest galaxy to our Milky Way. The Andromeda Galaxy aka M31 is located 2.5 million ly and can be seen with the unaided eye from dark skies on a moonless night. Along side of the Andromeda are two satellite galaxies, M32 and M110. A telescope will show a few dust lanes of M31 as well as its star cloud. Edwin Hubble imaged the Andromeda galaxy on October 6, 1923. Observing a predictable fading and brightening of the Cepheid variable star known as “V1”, it was determined the Milky Way was not the only galaxy in the universe. Latest measurements have revised the number of galaxies to two trillion in the known universe.

From the first discovery of an exoplanet around a sun-like star back in 1995, thousands or exoplanets have been discovered orbiting distant stars. Two of these parent stars can be seen with the unaided eye. At the time of its historic discovery, 51 Pegasi b was unofficially dubbed Bellerophon and later named Dimidium. It is located 50 ly away from us and orbits the magnitude 5.4 star in only 102 hours. We can also see the magnitude 4.1 Upsilon Andromeda at 44 ly away that have a family of four planets around it.

Comet 21P/Giacobini-Zinner is now putting on a good show reaches perihelion in early September. It could be as bright as magnitude 7 and pass within 0.39 astronomical units from Earth. The comet will pass the star Capella in Auriga on September 3 and the Cone Nebula on the 24th. This small 2 kilometre wide comet returns every 6.6 years and is the parent comet of the Draconids meteor shower that will peak next month on the 8-9. Only a few meteors are seen per hour but past history has shown an explosion of hundreds per hour has occurred so this is a shower to watch – just in case.

This year’s fall equinox occurs on September 23 and for a few weeks when moonlight is absent will be the best time to see the zodiacal light in the eastern sky before dawn. Here we see sunlit dust particles left over from the early solar system. It is fairly faint so dark sky conditions is a most. The pillar of faint light stretches on an angle pointing to the upper right from the horizon.

The planet Venus is sinking very close to the western horizon. It is now moving between the Sun and Earth and is showing some beautiful phase structure. On September 1 it sets at 7:54 p.m. Jupiter with its fantastic cloud structure and Galilean moons now sets just after 10 p.m. at the beginning of the month and by 8 p.m. by month’s end. Saturn is still located near the Lagoon Nebula in the Milky Way and by 4 a.m. local time. New moon will occur on Sept 9 with the full Harvest moon on the 26th.

Until next month, clear skies everyone.

Gary Boyle

Author: Gary BoyleeNews date: Saturday, September 1, 2018Category: Northern SkiesTweet::  Pages

New Youth Outreach Coordinator position announced

Recently the RASC successfully obtained a grant from the Trottier Foundation.

The grant is $75,000 a year for three years. The money is to be used to hire a Youth Outreach Coordinator.

The job was posted Friday on the Charity Village website

https://charityvillage.com/app/job-listings/714d3ff1-25a2-e811-80d3-14187768272a?search=true

 

Attracting younger people to join the Society has long been a challenge.

This new hire will be responsible for developing and running youth programs across the country.

The goal is to reach more young people and introduce them to astronomy.

 

Our centres are actively running excellent outreach programs and reach thousands of young people each year.

This coordinator position is meant to support these volunteers and share resources across all 28 centres.

We hope Centres will participate in this program as it is meant to be a national effort.

 

The position includes the following activities:

 

  • Conduct an inventory of current youth astronomy programming, activities and resources
  • Assess and identify best practices and materials to be used in a national youth astronomy program
  • Recruit a youth committee for program development, promotion and implementation
  • Develop RASC astronomy youth programming, educational materials and web content
  • Establish connections and long term relationships with local communities, schools etc
  • Disseminate and promote youth programs and resources to centres, members and the general public
  • Deliver national youth programming
  • Monitor and evaluate impact/effectiveness of the youth program
  • Develop partnerships with other youth /astronomy / science organizations to achieve program goals
  • Assess and evaluate outcomes

We hope to set aside time at the GA in Toronto next June to run training sessions with those interested in running these programs at their centres.

I am very excited about this project – it is the first time the Society has obtained a grant to hire a skilled individual to develop a specific national astronomy education program.

Please let me know if you have any questions about this program or are interested in participating in it.

 

J. Randy Attwood

Executive Director

Royal Astronomical Society of Canada

 

 

 

 

 

Author: Randy AttwoodeNews date: Monday, August 20, 2018Category: AnnouncementseNews Tag: youth outreach coordinatorjobTweet::  Pages

The Sky This Month - August 2018

Draco The Dragon

Ursa Major places a key role in helping identify other constellations such as Ursa Minor and namely the North Star. Located between these two iconic asterisms is Draco the Dragon. Its overall size measures 1,083 square degrees of sky and ranks eighth largest overall. No less than fourteen stars make up the Dragon’s asterism which begins with its head situated above the constellation Hercules.  

We presently refer to Polaris as the North or Pole Star. Such has not always the case. If we can go back in time to in 2787 BC, we would see Thuban (alpha Draconis) was the pole star at the time. This position slowly changes during the precession of Earth’s axis. Just as a spinning top slows down, its axis begins to wobble. Since Earth’s axis is tilted 23.5 degrees, the circle of precession also measures 23.5 degree wide and takes the 26,000 years to complete one revolution. In fact the star Vega will be somewhat the North Star 12,000 years from now. The same polar shift occurs in the southern hemisphere as well.

Thuban is a magnitude 3.6 giant star located 310 light years from us and appear to harbour an unseen companion that orbits every 51 days. Thuban is a white giant star of spectral class A0. Its surface temperature registers at 9800 Kelvin but shines a rare five times brighter than what it should be and 300 times more luminous than our Sun.

Now move eleven degrees to Edasich which is a K2 giant located 101 light years away. Edasich is one of the ten stars in Draco that have at least one orbiting extrasolar planet named Hypatia. Discovered in 2001, Iota Draconis b has the mass 8.9 times that of Jupiters and orbits once every 536 days.Half way between Iota and Theta Draconis is a fantastic group of elongated structures. They are NGC 5981, 5982, and 5985 with magnitudes of 12.9, 11.0 and 11.1 respectively. With distances estimated to be 170 million, 120 million and 180 million light years. Another fantastic edge-on galaxy is NGC 5907 also known as the Splinter or Knife Galaxy. It is only 56 million light years away and glows at magnitude 10.1. Measuring 11.3 arc minutes by 1.8 arc minutes, NGC 5907 is a must to hunt down and image.

The Cat’s Eye Nebula catalogued as NGC 6543 is a planetary nebula that lies 3,262 light years from us with a magnitude of 8.1. There is a strange structure to the remains of the central dead star. The theoretical cause is what was thought to be one central star is actually a binary star system. Some 10 arc minutes east of the Cat’s Eye is a real challenge. NGC 6552 is a magnitude 14.6 irregular spiral galaxy located an estimated 370 million ly away.

The Perseid meteor shower is active from July 17 to August 26 with best nights viewing at its peak on the 11/12 and again on the 12/13 and with no moon interference you should see more than 100 meteors per hour. The key is to find wide open spaces away from city lights, pack a lawn chair and enjoy. The particles strike the atmosphere at 60 km/sec and the Perseids also produce bright fireballs. 

Over the next weeks and months you should notice Mars begin to shrink in size and fade. The red planet was well publicized by the media during its closest approach since 2003 and peak the public’s interest to step outside at night and the lovely night sky. Mars is now up in the south east as the Sun sets. The planet Saturn is still in immersed in the Milky Way and forms a nice trio with the Lagoon and Trifid Nebulas.

The ringed planet sets just before 3 a.m. local time on the first of the month. In the lower western sky we see Jupiter that now sets at midnight. Venus has passed greatest angular distance from the Sun (elongation) and will begin to set lower and earlier as the nights tick by. This is my favourite time to follow Venus in a telescope. As Venus moves between the Earth and the Sun, its phase will change from half lit to crescent as well as grow in size.  

This month’s new Moon is slated for the 11th. Take advantage three nights before and after to enjoy the dark skies away from city light. The Milky Way is a sight only appreciated in person. The full Sturgeon Moon will occur on August 26.

Until next month, clear skies everyone.

Gary Boyle

Author: Gary BoyleeNews date: Wednesday, August 1, 2018Category: Northern SkiesTweet::  Pages

The Sky This Month - July 2018

The Milky Way and Big Bold Mars

Opposed to the Big Dipper that is seen all year round, Sagittarius the Archer appears low in the south skies for only a few months. With so many celestial objects to hunt down, we definitely have our work cut out.

To fully appreciate the majesty of the night, head out to the countryside on a moonless night and prepared to be dazzled. Looking at Sagittarius as well as the eastern half of Scorpius, there appears to be a misty haze amongst the distant stars. This cosmic haze is the glow of literally billions of suns that make up our Milky Way Galaxy.

One of my favourite globular clusters in Sagittarius is M22. It is located some two and a half degrees to the upper left of the top star of the teapot named Kaus Borealis. In a telescope it appears as an even distribution of stars. Situated at more than ten thousand light years (ly) away, M22 houses an estimated 100,000 stars. At magnitude 5.2and is easily picked up without optical aid.

One of the best examples of a stellar nursery is the Lagoon Nebula or M8. Just look a few degrees north of the star Alnasl, a spectral type K1 star located 97 ly away. This star has a brightness that equals 64 times that of the Sun, has a surface temperature of 4800 degrees Kelvin and is 12 times the Sun’s radius.

M8 resides about 5,000 ly away and takes up two lunar diameters of sky. The hydrogen gas cloud is being lit up by hot, infant stars. To the left of the gas cloud is an extremely young cluster catalogued as NGC 6530 containing about 100. A bit north and west is M20 aka the Trifid Nebula. Photos reveal a nice impression of a flower petal of red and blue. Also at 5,000 ly, the Trifid is considered an open cluster with nebulosity.

The next cosmic maternity ward is M17 that goes by a few names such as Swan Nebula, Horseshoe and even the Lobster from observers in the southern hemisphere. Any way you say it, this beautiful shell of interstellar gas and dust is forming an estimated 35 stars which are embedded deep in the nebulosity and not readily resolved. The very young stars are causing the region to glow.

With wide angle binoculars, you can hunt down numerous interstellar clouds that appear dark by blocking starlight. You will need dark skies and a very clear south. One good star chart for locating these dark objects is the old Skalnate Pleso sky charts which I have owned since the 1970’s. Even in our hi-tech world, you still can’t replace the old faithful star charts.

Let’s take a few moments and hop over to Scorpius. The orangey coloured star called Antares is listed at magnitude 1.1 and is the 13th brightest star in the sky. At a distance of about 600 ly, this supergiant star that is so large, if we replaced it with the Sun its boundaries would end somewhere between the asteroid belt and mighty Jupiter.

Moving one and a quarter degrees to the west of Antares is M4, a magnitude 5.6 globular cluster. This loose cluster by nature is estimated to be 7,200 ly from us and close to 75 ly wide. It takes up a little more that the area of the full Moon and contains 43 known variable stars. Ptolemy’s cluster (M7) is large, scattered and shines at magnitude 3.8 and is less than 1,000 ly away. This open cluster is bright enough to reflect off a calm lake. What a sight in any optical instrument.

Move up half way to the Scorpion’s top claw to locate M80. This is one of the densest globulars in the sky. Large scopes are needed to resolve stars to the center. This 8th magnitude cluster has a diameter of around 90 ly and is estimated to be some 36,000 ly from us. It is pretty rare to hear of a nova in a globular cluster but this was the case in 1860.

Higher up along the Milky Way is one of the prettiest open clusters buried in the Scutum Star Cloud. Commonly known as the Wild Duck cluster, M11 contains and estimated 500 stars brighter than 14 magnitude. Looking at this object in a telescope, you will see a bright star close to the middle of the cluster. This single sun is simply in the line of sight and not physically part of the cluster.

Venus is still high in the western sky and will form a nice conjunction on July 9 with the star Regulus. Venus is almost half lit and is spectacular in a telescope. Jupiter is very high in the sky and past the meridian. Every night will show a completely different orientation of the four main Galilean moons and in fact an elapsed hour will show subtle positional change. A complete timetable of Jupiter’s moons crossing the planet along with their shadows is found in the 2018 RASC Observer’s Handbook. Jupiter sets just after 2 a.m. at the beginning of the month. The moon will be about Jupiter on the 20th which also happens to be the 49th anniversary of humans setting foot on the moon. Saturn is past opposition and is above the southern horizon as the sky darkens.

The long awaited opposition of Mars occurs on July 27 with the closest approach on the 31st.  The planet rises around 11 p.m. on July 1 and by 9 p.m. at month’s end. At is brightest the red planet will even be brighter than Jupiter. Mars will be 57.6 million km from us at its closest compared to 56 million back in 2003. Although our two planets come close about every 26 months, it is the seventh opposition that we get very close. As luck would have it there is a global dust storm occurring on the red planet right now. This is hiding surface detail which would have been spectacular. A total lunar eclipse occurs on the 27th but will not be visible from North America.

This month’s new moon occurs on July 12 with the full moon on the 27.

Until next month, clear skies everyone.

Gary Boyle

Author: Gary BoyleeNews date: Sunday, July 1, 2018Category: Northern SkiesTweet::  Pages