Constellation Profile - Sagittarius

The constellation of Sagittarius is well known as it one of the most popular in the zodiac.  The zodiac is a region in the sky approximately 8° North and South of the ecliptic.  This is the area of the sky the Sun, Moon and Planets transit.  If you were to look at the planets in the sky they would likely be within the borders of a zodiac constellation.

There are several myths associated with Sagittarius.  It is well known that this constellation represents the archer.  The Greeks represent Sagittarius as a centaur who is aiming his arrow toward the heart of Scorpius--the bright red star Antares.  In mythological tradition the scorpion killed Orion and is now seen chasing the great hunter out of the sky in the Spring.  Sagittarius keeps a watchful eye on Scorpius to ensure he does not sting Orion again.

The chief librarian at the Library of Alexandria, Eratosthenes, believed that Sagittarius represented a satyr and not a centaur.  The satyr Crotus is a mythological being known to be the son of Pan.  He is credited with inventing archery and was an excellent hunter.  He kept the company of the Muses and is also credited with inventing applause.  The Muses, in their great love for him, requested Zeus to put him in the sky.

Sagittarius (Artist Interpretation)

For observers in Calgary, most of Sagittarius can be found transiting the southern sky just above the horizon throughout the Summer around midnight.  If you are at a dark site you will notice the Milky Way and the Galactic Center find their home in this constellation.  Within the constellation, the radio signal known as Sagittarius A* is thought to be the location of the supermassive black hole around which our galaxy orbits.

Sagittarius was the most difficult constellation to map so far in my journey through the sky.  It's declination runs from about 12°S to 46°S.  At the latitude in Calgary (~51°N) we can only see to approximately 39°S depending on altitude and topography.  This rendered the southern regions of the constellation forever buried beneath the horizon.  The Summer is the best time to map Sagittarius as it reaches its greatest height above the horizon while the Sun is on the opposite side of the Earth.  This poses additional challenges from 51°N with constant astronomical twilight from the end of May to mid-July.  The Summer also offers a plethora of bugs that can completely destroy an entire night of observing.

I mapped Sagittarius over the course of 3 separate calendar days.  I started late on July 9, 2018 which carried me into the morning of July 10, 2018.  I went out during the evening of July 11, 2018 to a high altitude location with a clear view of the southern horizon.  On this night I was able to find Epsilon, Eta and Theta Sagittarii hovering just a few degrees above the horizon.  Alpha, Beta, Iota and Kappa Sagittarii are permanently below the horizon from Calgary and thus so indicated on the observation record below.

Sagittarius Observation Record

Sagittarius is the 15th largest constellation and it contains many Bayer stars.  It took a long time scaling my observations onto the Powerpoint slide above.

There are several interesting asterisms that can be seen above.  The most famous is the teapot.  The westernmost part of the constellation contains many bright stars in the pattern of a teapot.  Adding to the effect is a lemon wedge on a spoon to the upper left of the teapot.  The Milky Way flows right through the teapot making it look like an enormous amount of steam billowing out.  This is why a spoon is needed, you don't want to get your fingers too close to that steam!

Another asterism, although less famous, is the Terebellum.  The Terebellum is a quadrilateral pattern on the easternmost regions of the constellation.  They are close together in the sky but in reality they are not gravitationally linked at all.

There are many famous deep sky objects found within the boundaries of the constellation.  Fifteen Messier objects call this region of the sky home.  The table below highlights these objects.

Messier	Name/Type
M8	The Lagoon Nebula (Emission Nebula)
M17	The Omega Nebula, The Swan Nebula, The Checkmark Nebula (Emission Nebula)
M18	Open Cluster
M20	The Trifid Nebula (Open Cluster, Emission Nebula, Reflection Nebula, Dark Nebula)
M21	Open Cluster
M22	Globular Cluster
M23	Open Cluster
M24	The Sagittarius Star Cloud (Open Cluster)
M25	Open Cluster
M28	Globular Cluster
M54	Globular Cluster
M55	Globular Cluster
M69	Globular Cluster
M70	Globular Cluster
M75	Globular Cluster

This rich area of the sky is filled with many open clusters and globular clusters.  There are also several notable nebulae that have been viewed over the centuries.  I have viewed the deep sky objects on this list and I can vouch for their beauty.  I will revisit this area of the sky each Summer.

2018 Week 29: (July 15-July 21)

Summer is in full swing and the weather for astronomy has been amazing.  There is no smoke in the air and the clouds have stayed away.  The weather for the upcoming week is looking great!  There are a few things to check out in the sky.  The table below showcases our skies for the week!

Date	Event
July 15	Regulus 1.8°S of Moon
July 15	Venus 1.6°S of Moon
July 19	First Quarter
July 20	Jupiter 4° of Moon

An excellent article written by Nicole Mortillaro highlights the 5 naked eye planets that can be seen in the sky!  Check it out and see if you can spot them all; Mercury is a tough nut to crack sometimes, though.

http://www.cbc.ca/news/technology/5-planets-night-sky-1.4745932

The Moon is beginning another lunar cycle and will be seen as a waxing crescent in the western sky.  It will pair up with Leo's bright star Regulus on Sunday while hanging out with Venus.  It cruises on to its first quarter phase several days later.

The Moon will then appear alongside the largest planet, Jupiter, next Friday.

This raises an interesting point.  If you would like to check out Jupiter, be sure to see it soon.  Jupiter is slowly approaching the western horizon and will soon be soaked in sunshine.  Also, as it gets lower in the sky the atmospheric interference will disrupt the seeing such that it will look like it's boiling!

Saturn is amazing at this time of the year as it stands high in the southern sky at midnight.  There are 11 Messier objects within 8° of our ringed friend.  A telescope will help pull these into view.  Alternatively you could try binoculars.  I was able to see most of them from light polluted suburban skies with a pair just the other night.  The image below highlights these special objects.

Saturn and Friends

Following Saturn is the Greek war god Mars.  The red planet is usually a boring object in the sky, barely shining bright enough to tell it apart from a star.  However, every 28 months Mars reaches what is known as opposition.  The image below illustrates this orbital geometry.  We are fortunate this year that Mars and Earth are extremely close to each other in their elliptical orbits.

Mars Oppositions 2012-2027 (Image Credit: Martin J Powell, www.nakedeyeplanets.com)

The unfortunate news about Mars is there is currently a significant global dust storm.  This storm is shrouding the planet against our peering eyes.  It is nearly impossible to make out any significant features on the surface.  The article below goes into this in more detail.

https://www.skyandtelescope.com/astronomy-news/is-the-mars-opposition-already-over/

The Opportunity rover is currently in safe mode as it is powered by solar and is not getting enough energy.  Curiosity, on the other hand, is powered by radioisotopes and can function seamlessly through storms like this.  Curiosity even took a selfie to commemorate the storm.

Curiosity (Image Credit: NASA/JPL-Caltech/MSSS

I hope you take the time to get outside and enjoy the night sky.  If you plan on leaving the city to go camping, bring along some binoculars and sit under the stars.  The sky is an amazing place full of endless things to observe.

The Milky Way Galaxy

The Milky Way Galaxy is our home.  We live on a planet that orbits a star that, ultimately, orbits our galaxy's center of mass.  There is a black hole residing in the center of our galaxy that is approximately 4 million solar masses.  If you think the Sun is big, imagine 4 million of them packed into the volume of space inside the orbit of Mercury.

What is a galaxy?

According to the Oxford Dictionary, a galaxy is a system of millions or billions of stars, together with gas and dust, held together by gravitational attraction.

The etymology of the word comes from the Greek word for 'Milky'.  This is a direct reference to the 'milky'-like appearance we can see in the sky from the arms of our own galaxy.

The image below is a map of our own galaxy.  Our Solar System resides on the inside edge of the Orion Spur.  When we look toward the galactic center we are seeing stars from our own spur, stars from the Sagittarius Arm and stars from the Scutum-Centaurus Arm.

Milky Way Map (Image Credit: NASA)

The Orion Spur is quite a minor arm in our galaxy.  It is only 3,500 light years wide and 10,000 long.  When we peer out towards the constellation Sagittarius we are looking toward the galactic center.  If you are in a dark sight you will see this brilliant 'milky' glow of billions of stars.  Also, when we peer out towards the constellation Perseus we will see the stars from that arm.

Below are some quick facts about The Milky Way:

Characteristic	Value
Type	Barred Spiral
Diameter	100,000-180,000 Light Years
Mass	800 Billion - 1.5 Trillion Solar Masses
Number of Stars	100-400 Billion
Cosmic Year	240 Million Years

Our galaxy has a mass of more than a trillion Suns.  This is incredible.  Our Sun revolves around the Milky Way's black hole every 240 million years.

It would take light more than 100,000 years to traverse the entire diameter of our galaxy.  Living on Earth with most distances measured in kilometers or miles, it is difficult to conceive the enormity of our galaxy.  This would translate into nearly a quintillion kilometers!

There are interesting things to view in each of the arms in the region near us.  Our home Orion Spur contains amazing sights such as the Orion Nebula, Dumbbell Nebula, The Pleiades and the Beehive Cluster.

If we were to examine objects in the Sagittarius Arm we would see such things as the Eagle Nebula, Omega (Swan) Nebula, and the Sagittarius Star Cloud.

Looking toward the anti-galactic center in the Perseus Arm we could see the Crab Nebula and many Open Clusters such as M36, M37 and M38 within Auriga.

The image below shows an inverted map of the galaxy with the constellations listed.  As you can see, relative to Earth, Sagittarius is directly in line with the Galactic Centre while Auriga is toward the anti-center.

Milky Way Constellations

The Milky Way is just one of billions (possibly more than a trillion) galaxies found throughout the Universe.  We can see other galaxies in our night sky with sometimes no more than our own eyes.  The Magellanic Clouds are satellite galaxies to our own and can be seen in the southern hemisphere skies.  For those living in Northern climes, the Andromeda Galaxy can be seen outside of the urban shine.  At 2.5 million light years away it is the closest major galaxy to our own.  At some point in the far distant future (~4 billion years) it will collide with our own causing a galactic merger.

All of the stars you can see in our night sky call the Milky Way their home.  If you can make your way to a dark site be sure to enjoy the view of the milky arms that form our galaxy.

2018 Week 28: (July 8-July 14)

This upcoming week looks to be very warm with clear skies.  This is good because there are many sights in the sky to check out!  The table below highlights these events!

Date	Event
July 9	Venus 1.1°N of Regulus
July 10	Aldebaran 1.1°S of Moon (Occultation)
July 10	Jupiter Stationary
July 11	Mercury Greatest Elongation East
July 12	Pluto at Opposition
July 12	New Moon (Supermoon)
July 12	Partial Solar Eclipse (Southeastern Australia)
July 14	Moon 1.4°S of Beehive (M44)
July 14	Mercury 2°S of Moon

We start off the week with a close conjunction of Venus and Regulus, the heart of Leo the Lion.  This will occur in the western sky just after sunset.  If you are lucky you may be able to glimpse the smallest planet, Mercury.  Mercury will reach its greatest elongation East on Wednesday, making it easier to see.  A map of this region is shown below.

Venus/Regulus Conjunction

What is more exciting is about 4 hours later the waning crescent Moon will occult Aldebaran in the morning sky.  Unfortunately this happens just out of our view below the eastern horizon.  They will, however, be in the same telescopic field as they rise just before the Sun in the morning.

Jupiter will continue its prograde motion on Tuesday and once again move eastward compared to the background stars.  You can still catch the large planet in Libra, a little more than 1°W of the Alpha star known as Zubenelgenubi.

The dwarf planet Pluto will be at opposition on Thursday.  Pluto is situated in the starry region of the constellation Sagittarius, only 10 arcminutes from the rural naked eye star 50 Sagittarii.  This would be a great challenge object for those with somewhat large aperture telescopes.  Pluto will be at magnitude 14.2 with a declination of 21°S.  This will be fairly difficult for Calgary observers.  Find a clear view of the southern horizon, stick 50 Sag in your view and sketch the field.  Repeat this several times and see if any of the sketched 'stars' have moved.  That will be Pluto.  The only good news is the Moon will be new, thus removing it as a potential source of light pollution.

Pluto (Image Credit: NASA)

The New Moon this month will be considered a Supermoon.  Why haven't you heard about this in the media?  It doesn't have the same hype as when the Full Moon is a Supermoon.  However, the tides will likely be noticeably higher if you are lying on a beach somewhere enjoying the Summer.

There will be a partial solar eclipse occurring on July 13, however do not get too excited.  It will be visible for the very edge of southeastern Australia and all of Tasmania.

The 14th of July we will once again start seeing the waxing crescent Moon in the sunset sky.  It will be in conjunction with the Beehive Cluster and Mercury on this night.  The conjunction with the Beehive will occur when the Sun is still up so you will not be able to see it from Calgary.  However, if you look at the western horizon right after the sun goes down you will be able to catch the Moon and Mercury within the same binocular field.  The next night the Moon will be hanging around Venus and 3 Messier Objects!  That is a story for next week.

Constellation Profile - Lyra

The constellation of Lyra in the Northern Hemisphere is quite well known.  It contains the fifth brightest star in the night sky (Vega - Magnitude 0.03) and the second brightest star in the North.  Vega forms the brightest corner of the Summer Triangle and hovers directly overhead during the hot months.

Lyra was one of the original 48 constellations listed by Ptolemy during the second century and has endured these many years throughout astronomy texts.  Lyra is bordered by several other bright constellations.  Hercules, Cygnus and Draco all surround the diminutive Lyre.

Lyra was immortalized by the Greeks with the myth of the legendary harpist Orpheus.  Orpheus was a mythological musician and poet in Ancient Greece and received a Lyra from Apollo himself; who was possibly his father.  So great was Orpheus' power that he could charm all things with his music, including streams, rivers and stones.

Orpheus accompanied Jason and the Argonauts on their great adventure.  He used his skills to drown out the songs of the sirens with his beautiful music and saved the entire crew from certain death.

The tragedy of his life came with his only true love, Eurydice.  She was a nymph (minor Greek deity) and a women of exceptional beauty.  Orpheus loved her very much and played joyful music at their wedding.  At one point shortly after the wedding she stepped on a poisonous viper and perished.  So great was the sorrow or Orpheus that he continued to play such mournful music that all who listened were affected.  The gods instructed him to head for the underworld, certain death without divine protection, to retrieve his wife.  He reached the underworld god Hades and even charmed him with his music.  Hades and his wife Persephone were moved and allowed Orpheus to return with Eurydice on the condition he does not look upon her until they reach the surface.  A few feet from the surface Orpheus feared he was fooled and looked back.  He saw the shade of his wife return to the underworld for eternity.

Living a life of grief Orpheus met his death in a number of recorded ways.  It was said that his spurned suitors threw rocks and sticks at him but they could not hit him as the rocks and sticks loved his music too much.  Overwhelmed by his suitors and unable to charm he was torn apart.  The muses (his mother being Calliope, the muse of poetry and his singing instructor) carried his lyre to the heavens and his soul was reunited with Eurydice in the underworld.  The lyre in the heavens is said to represent the constellation Lyra.

The constellation mapping I performed on July 4, 2018 is shown below.

Lyra Observation Record

Vega is an important star in astronomy history.  It was the first star, besides our Sun, to have its spectrum recorded.  This was done by the American astronomer Henry Draper whose untimely death lead to the continuation of his work by many women at the Harvard College Observatory during the late 1800s.  Vega was the northern pole star at the end of the last ice age around 12,000 BC and will be once again in another 12,000 years.

Another one of my favourite stars is Delta Lyrae consisting of two visible companions.  Delta 1 Lyrae is a bright blue colour and Delta 2 Lyrae is a red giant.  These two stars form a beautiful contrast in colours through binoculars or a telescope.

Epsilon Lyrae is famously known as the double-double.  Two of the stars are easily resolved in binoculars.  The trick is that these two stars each form their own pair which can be seen through a good telescope and a still atmosphere.  The two tighter pairs are separated by only 2.5 arcseconds, making it a good optical challenge for many observers.

There are two Messier Objects found within the Lyre.  Messier 56 is a globular cluster located approximately halfway between Albireo (double star in Cygnus) and Gamma Lyrae.  The other Messier Object is M57, the famous Ring Nebula.  This is a beautiful sight in any telescope.  It lies right between Beta and Gamma Lyrae making it very easy to find.  A red giant star expelled its outer gas and became a white dwarf.  The gas is thus illuminated by this dwarf and shines as a planetary nebula.

M57 - Ring Nebula

There is also an assortment of other deep-sky objects found throughout Lyra that are quite dim and require a large aperture and/or dark skies to be able to locate.

M56

Lyra is home to several meteor showers with the most prominent simply known as the 'Lyrids'.  The Lyrids peak around April 22-23 each Spring and rates can reach upwards of 20 meteors per hour.  On occasion the Lyrids have been known to storm at more than 100 per hour every 60 years with the next suspected outbreak occurring around 2042.  An interesting fact about the Lyrids is they have been recorded back to 687 BC marking it as the earliest recorded meteor shower.

2018 RASC General Assembly

The Royal Astronomical Society of Canada is a nationwide collaboration of more than 5000 people united by their passion for the sky.  It was founded in Toronto on December 1, 1868; a year after Confederation.  In 1903, Edward VII, King of England was "graciously please to grant permission to the astronomical society to adopt the title of Royal Astronomical Society of Canada.  Since the beginning of the 20th century, the RASC has continued to expand and there are 28 centres across Canada.

One of the main missions of the RASC is to provide public education and hands-on experiences.  We want as many people as possible to explore the wonder of space.  Anyone can join the society and become involved in this great mission.  A link is provided below.

https://secure.rasc.ca/Portal/Membership/RASC/Membership/JOIN_10_MemberType.aspx

The benefits of membership include a full subscription to SkyNews magazine and the RASC Journal.  An annual copy of the internationally renowned Observer's Handbook is also provided.  The membership will also provide you with access to observatory facilities you can use for your own personal tour of the sky.  Informative lectures and social events are provided several times a month and many people are there help you learn the sky.

This year we celebrated the 150th year of the founding of the Society right here in Calgary.  It was a fun filled weekend with many lectures, great food and a wonderful exchange of ideas.

Royal Astronomical Society of Canada - 150 Years

To celebrate the 150th anniversary the Royal Canadian Mint unveiled a commemorative coin that contained a real meteorite.

Also, Canada Post surprised us with a commemorative stamp set created specifically to celebrate 150 great years of astronomy across our nation.  (The Calgary Centre's own Alan Dyer (http://www.amazingsky.com/) was the photographer for the beautiful aurora stamp.

Canada Post Commemorative Stamp with Alan Dyer

The stamps are photographs of the Aurora and the Milky Way with the constellations laid across them.  They are available at most post offices across the country; be sure to pick up a set!

Aurora and Milky Way Stamps

Unfortunately I missed the Friday Morning session where Dr. Robert Thirsk gave an amazing address to the delegates.  However, in the afternoon, I had the opportunity to take a class from Alan Dyer on processing nightscapes, deep-sky objects and timelapses.  This three and a half hour class was intensive and extremely useful.  I would suggest that if you have the opportunity you must take a class from Alan.  Workshops are posted on his webpage below.

http://www.amazingsky.com/

Later in the evening, Dr Fereshteh Rajabi gave an excellent talk on Dicke's Superradiance in Astrophysics.  It was wonderful to go back to my roots in Quantum Physics and see it applied to my new hobby of astronomy!  The papers she collaborated on used for the talk are on the free arXiv owned by Cornell University.  For those interested in learning more I have provided a link to all of these papers through Google Drive below.

https://drive.google.com/open?id=1RpIk55kJKZQxzDI68SLtpEmumy8aF01g

Although we were unable to make it the next day had poster and paper presentations throughout the greater part of the afternoon.  Members of the youth were involved in some of these posters and they were fabulous.

We joined the assembly again for dinner and I had the opportunity to sit next to our Helen Sawyer Hogg Lecturer, Emily Lakdawalla.  Emily is a planetary geologist working with the Planetary Society (http://www.planetary.org/).  She is an internationally admired space communicator who works tirelessly to share the wonder of science.  This made her a perfect fit for speaking to the RASC membership and the public of Calgary.  At dinner she spent time teaching us all the details about the moon rock I had at the table.  It was amazing to see the passion in her eyes as she performed this 'rock whispering'.  Later in the evening she taught us more about another moon rock.

Moon Rock Analysis

Many people later attended her keynote address about the Golden Age of Solar System Exploration.  We learned about missions to the planets and objects located throughout our Solar System.  Starting at Pluto and moving our way back toward Earth we learned so much about the vast frontiers we are currently pushing in the 21st century.  It inspired us to learn more about our Solar System and excited us for the many upcoming missions taking place in the near future.

Emily Lakdawalla - Keynote Speaker

The General Assembly continued through Sunday with Part 2 and 3 of "A Shared Sky: The RASC at 150".  Following later in the evening was the Banquet with keynote speaker Dr. Tanya Harrison.  Also known as "Tanya of Mars", she too is a planetary geologist who is on the science team for the Mars Opportunity Rover.  Her webpage is a must see and it is linked below.

http://tanyaofmars.com/

We unfortunately were unable to attend the Sunday session of the assembly but understand it was absolutely amazing.

Astronomy is Calgary and Canada is strong and it is my strong desire that you get involved in free local events happening each month.  Turn your eyes to the sky and see the wonder that stretches forever.

2018 Week 27: (July 1-July 7)

We now begin the second half of 2018 with many bright planets in the sky.  These are sometimes referred to as the planets of antiquity because they were well know throughout the dawn of civilization.  The chart below highlights this upcoming week in the sky.

Date	Event
July 4	Mercury 0.7°S of Beehive Cluster (M44)
July 6	Last Quarter
July 6	Earth at aphelion

The weather is looking to be unstable until later in the week and we may not have a chance to see any stars or planets until then.  However, after that all telescopes should be focused on Mars.  I have been talking about our red planet for a few weeks now for good reason.  Mars will be under 58 million kilometers away from Earth.  This is very close.  In 2003 Mars was about 56 million kilometers away from Earth at the closest opposition in 60,000 years.  The opposition two years ago Mars was more than 75 million kilometers away.  It will not be this close again until 2035 so do not miss it!

Mars can be found in the southeast sky this week rising shortly before midnight; you can't miss it!

At opposition, Mars will be be greater than 24.3 arcseconds in diameter which is more than enough to see amazing surface features through a telescope.  It will be magnitude -2.8 and brighter than Jupiter.  There is currently a planet-wide dust storm that is muting some of the major features but we hope it settles down in time for opposition.

Mars Sizes 2018

There are several events being held around Calgary to celebrate this close opposition of Mars.

The Rothney Astrophysical Observatory is hosting an observing night on July 31 from 10pm-1am that will be held if there is fair weather.  A link to this event is provided below.

https://www.facebook.com/events/2130418370547375/

All-Star Telescope just south of Didsbury will also be hosting an observing night on the 28th of July at 8pm.  You can find a link to this event below.

https://www.all-startelescope.com/information/observer-nights

I would suggest getting out to one of these events or contacting me during July and August to see where I will be observing from; Mars will be the top of my list for all nights throughout the Summer.  You are always welcome to join!

If you are at one of these events check out Sky and Telescope's Mars Profiler application that shows you what side of Mars is currently facing Earth.  The link is provided below.

http://wwwcdn.skyandtelescope.com/wp-content/plugins/observing-tools/mars_profiler/mars.html

Of course Mars is not the only bright planet residing in our Summer sky!  Jupiter and Saturn are prominently placed in the southern sky throughout most of the season.  Venus is sitting in the West and certainly observable in the early evenings.

In other news, there are no significant launches scheduled for this week.  Check back next week when the Russians send some cargo to the International Space Station.

Launches:

Date	Event
-	-

Stay tuned for more events and seek opportunities to be out under the stars! (and planets!)