What is an Aurora?

An aurora is a geomagnetic phenomenon that causes bright lights to appear above the Earth's polar regions.  The Sun is particularly active, especially during what is known as a solar maximum.  The Sun cycles approximately 11 years on average and maxima are characterized by an abundant number of sunspots.  I took the image below last Summer and it has a few sunspots.  We are currently heading into a solar minimum and thus the intensity and frequency of the aurora will be less.

Sun with Sunspots

The Sun expels ionized gas, electrons, protons and alpha particles.  These particles make it to the Earth 150 million kilometers away.  Since they are charged particles they get captured by the Earth's magnetic field and interact with matter present in our atmosphere.  An atom consists of a nucleus(protons and neutrons) surrounded by a cloud of electrons.  When energetic particles from the Sun interact with these atoms, electrons are excited to a higher energy state.  When the electrons drop back down to a lower energy state they emit photons at a specific wavelength.  This is what happens with neons signs.  Electricity excites the neon electrons to a higher energy level and when they drop back down you get the distinctive red/pink colour.

Oxygen in the upper atmosphere works much like the neon gas in a tube except on a larger scale.  Excited oxygen emits strongly around 558nm -- Green, while Nitrogen(lower in the atmosphere) causes deep blue and red colours.  Our eyes are poor receptors for colour vision at night.  This causes auroras to seem colourless when fairly dim.  It is only after we become adapted to the darkness and the intensity of the aurora increases can we see the colours.

What are the best ways to see the aurora from your location?

The first thing I would suggest is getting away from any urban setting.  Light pollution will significantly hinder any hope at seeing these geomagnetic lights.  The next thing would be to have a good computer program, social media source or mobile application that will crunch the large amount of data that goes into aurora forecasting.

We had a presentation in February 2017 on this very topic.  The consensus seemed the best mobile application would be "Aurorasaurus" by the New Mexico Consortium.  It is a free application that crowdsources space weather forecasting.  It uses realtime observations to create a map of where the aurora can be seen.  This is much better than other sites that tend to be overly liberal in their predictions that will cause you to go out to your dark site and see nothing.

http://www.aurorasaurus.org/

They also have a twitter account for live, up to date information.  Just navigate to @TweetAurora on your twitter account.

There is a great facebook group for Alberta observers known as "Alberta Aurora Chasers".  Monitoring the activity on this page will give you a great idea when and where a perfect aurora will appear near you.  If these members are getting out their equipment for a light show maybe its time for you to cruise out to a dark site where you can see the northern sky.

https://www.facebook.com/groups/AlbertaAuroraChasers/

I have also found that Space Weather Live provides great information.  Typically I get excited when the Bz value is below -10nT and the Bt is greater than 10nT.  A link to this site is provided below.

https://www.spaceweatherlive.com/

If you live in Calgary your best bet will be to go North, East or West to give yourself some great northern dark skies.  If you travel South you will have an ugly artificial dome of light emanating from Calgary.  However, that does not eliminate the possibility of seeing the aurora just South of Calgary as I took this image below from DeWinton.

Aurora in DeWinton

Good luck chasing the aurora!  Keep your eye on the forecast pages as they can changed minute to minute!

2017 Week 9: (February 26-March 4)

This upcoming week has some interesting conjunctions in the sky.  Also, if you live in Southern South America or Southern Africa you will be able to see an annular solar eclipse on February 26.  A link to the visibility range of the eclipse is given below.

http://www.skyandtelescope.com/astronomy-news/february-26-annular-solar-eclipse/

This week begins a new lunar cycle so look at the Western horizon after the 26th to see a slim waxing crescent Moon peeking up from the mountains.  Venus begins its retrograde motion as it can be observed moving to the West against the backdrop of stars.  A dwarf planet located in the asteroid belt known as Ceres will be very close to the Moon Thursday evening.  Ceres is the largest object in the asteroid belt making up about a third of its total mass.  It will be magnitude 9.0, so pretty much only visible in a telescope or if you are really lucky in a large pair of binoculars.  The chart for astronomical activities for next week is shown below.

Date	Event
Feb 26	New Moon
Feb 27	Mars 0.6°N of Uranus
Mar 1	Mars 4°N of Moon
Mar 1	Neptune in conjunction with the Sun
Mar 2	Venus Stationary
Mar 2	Ceres 0.8°N of Moon
Mar 4	Aldebaran 0.2°S of Moon

An important conjunction will be Aldebaran with the Moon on the evening of March 4.  An excellent presentation at the last RASC meeting discussed the possibility of seeing a grazing occultation of Aldebaran.  At specific locations at the very North of the United States you will be able to see Aldebaran peek in and out from behind the Moon.  In Calgary we should see the Moon nearly cover the bright red eye of Taurus at an angular distance of 12'.  This will be a great sight to see in binoculars so point them towards the Moon next Saturday.  The last time the Moon occulted Aldebaran was in December of last year.  I took a poor hastily prepared image through my 8" reflector.  If you look closely you can see the star on the left hand side of the Moon.  Since the Moon was full I had to dim the Moon and enhance the brightness of the star in the image.  Successfully manipulating astronomical images is one of my goals for 2017 as I did not have too much luck with it last year.

Occultation of Aldebaran

Neptune will be in conjunction with the Sun next week and will begin to show up in the morning sky before sunrise.  I look forward to the summer when I can go out and search for this elusive planet lying more than four billion kilometers away.

Good luck finding clear skies next week we're in for some chilly weather.  However, there is some hope for near the end of the week with temperatures around the freezing mark.  When there is a break in the clouds take the opportunity to look up!

What is an Open Cluster?

I have mentioned open clusters several times when discussing certain Messier objects.  An open cluster is a loose distribution of stars that are bound together gravitationally.  Unlike globular clusters they are contained within the disk of the galaxy and not in the halo.  Open clusters typically contain less stars than a globular cluster and are considered relatively new.  Stars in an open cluster are formed from the same molecular cloud of gas.  Some of these clusters have shed their nebula through the stars' combined radiation pressure dispelling the gas from their gravitational hold.  An obvious example of an open cluster that still has a cloud of gas is the Trapezium in the heart of the Orion Nebula.

Messier 42 - Orion Nebula

The interesting thing about open clusters is they typically contain stars of approximately the same age.  Some stars are ejected from the cluster by interacting with other matter as they orbit the center of the galaxy.  An example of  cluster with thousands of stars is shown below in an image I took back in November.  This is the Wild Duck Cluster which is supposed to resemble a flock of flying ducks.  Honestly, I don't quite see that.  Any cluster could be construed to resemble a flock of birds.

Messier 11 - Wild Duck Cluster

An example of an open cluster with very few stars is shown below.  It is Messier 39, located in the rich constellation of Cygnus.  It has around 30 stars.

Messier 39

The trick to observing open clusters is to use a telescope with a relatively low focal length using a low power eyepiece.  Open clusters tend to be quite expansive as viewed from Earth and therefore lose their beauty when viewed under high magnification.  The Pleiades cluster expands nearly 2° across the sky and could not be viewed in its entirety under high powers.  The Hyades stretches nearly 6° and your best bet is probably just your own eye.  Binoculars are a wonderful instrument that can be used to view them.  .  I would recommend a moderate sized refractor with a wide field eyepiece.  In order to see the nebulosity associated with open clusters you are best off using a telescope to take a long exposure photograph.  Narrow band emission line filters sometimes help if it is an emission nebula but if it is a reflection nebula, a basic light pollution filter might be your best bet.

Messier 45 - Pleiades 

If it is clear, use Orion to fine the red eye of Taurus the bull to see the naked eye Hyades open cluster.  Above the Hyades you should be able to see the Pleiades.  See the viewing chart below!

Hyades and Pleiades Star Chart

What is an Exoplanet?

The first time I was exposed to exobiology I was twelve years old.  I received a Star Trek Collectible Card Game deck for Christmas and read each card intently.  One of the skills of some of the officers was exobiology.  Of course at the time I looked up the meaning but there was not much written about it.  Science teachers at school dismissed it as science fiction.  The Merriam-Webster dictionary defines exobiology as "a branch of biology concerned with the search for life outside the Earth and with the effects of extraterrestrial environments on living organisms."  I suppose if my science teachers were well read they would know the first NASA funded exobiology project was in 1959 and that it was certainly a legitimate field of study in the 1990s.  Today, many exobiologists (also known as astrobiologists) work all over the world in this growing field of study.

The timing of this blog entry coincides with some great news.  NASA announced today that a solar system was discovered containing seven Earth sized planets.  Three of these planets are in what is known as the habitable zone or 'Goldilocks Zone'.  Recall the fairy tale "Goldilocks and the Three Bears" where the titular character would find the object 'just right' for her use.  The habitable zone is a region around a star where, based on a set of criteria, a planet could support liquid water.  Liquid water is biochemically important to life.  Some have proposed the habitable zone be extended to include other solvents for theoretical organisms of different biochemistry.

The star at the center of this solar system is an ultra-cool dwarf star.  It is so cool that all seven of the planets in the system orbit closer to their host star than Mercury does to our own.  An artistic rendering of the star system is shown below courtesy of NASA/JPL-Caltech.

TRAPPIST-1 Star System (NASA/JPL-Caltech)

I reached out for a comment from Astronomer Dr. Sarah Rugheimer at the University of St. Andrews

"This discovery is very important for two reasons. One, these planets' atmospheres, should they exist, can be detected with JWST, providing a unique system with three habitable planets. Second, due to the ultracool host star they orbit, many questions remain about the stability of such planet atmospheres and the UV environment of the host star. These planets offer us a laboratory of a diversity of Earth-sized planets in one system to learn more about planetary evolution."

A link to her webpage is provided below:

http://www.st-andrews.ac.uk/~srm26/

Note: JWST - James Webb Space Telescope - to be launched 2019.

To answer the question posed as the title of this blog entry, an exoplanet is simple a planet orbiting a star that is not our sun.  Can you see them from your backyard? No.  However, backyard astronomers can plot light curves of variable stars.  A variable star is simple a star that's magnitude changes irregularly or at regular intervals.  In some cases when a planet transits across the face of a star its magnitude will decrease measurably.  Backyard astronomers can plot the magnitude of the star  over a specific time interval and note possibly regularities.  This information can be used for professional astronomers in their search for exoplanets.  There are several people in the Calgary Centre of the Royal Astronomical Society of Canada who do this very thing.

I hope you keep tuned for more news in the field of astrobiology and its influence on the way we see the universe!

Messier Objects - M38

The final Messier object in Auriga that I observed last Friday was M38.  M38 is an open cluster very similar to M37 except it has less stars and is about 3 times fainter.  I had a difficult time determining the identity of this object.  I moved the telescope past M36 and scanned the sky with the finderscope but had no luck.  There were too many clouds interfering with the observation on a low power finderscope.  I instead took to using the main scope to scan the sky.  I found a very faint cluster of stars and kept it at that location for around 15 minutes.  The clouds started to drift away and the cluster became brighter and I was able to identify it as M38.

A fainter cluster is only 30' away known as NGC 1907.  I was unable to observe this cluster at the time due to the cloud cover and the jubilation of finding M38.  When I have some time to revisit this area I will look for the apparent cross shape of M38 and NGC 1907.  I also hope to have the opportunity to take a picture to add to my observation log below.

M38 Observation Record

With fog, snow and temperatures far below seasonal for the next two weeks it seems as though there will be no opportunity for observations.  Saturday seems like it will be the clearest evening which is fortunate because there is an open house at the Rothney Astrophysical Observatory.  Orion, Taurus and Leo should make a great appearance.  I look forward to showing people the Orion Nebula for the first time in their life and seeing the look on their faces.

Messier Objects - M37

On Friday, February 17, 2017 I spent some time observing at the observatory.  Auriga and Orion were the only constellations that were cloud free at the time.  I used the telescope to find Beta Tauri (Elnath) and moved it up towards Theta Aurigae.  I found M36 as a sparse open cluster of several dozen relatively bright stars.  I moved the telescope across the line between Beta Tauri and Theta Aurigae until I saw another faint blurry patch of light in the finderscope.  When I looked through the main telescope I saw an amazing sight.  Messier 37 contained hundreds of stars, some too faint to be resolved.  Also, quite fortunately, M37 is part of the deep-sky observation requirements for the Explore the Universe certification. The observation log is provided below.

M37 Observation Record

Discovered in 1654 by Italian astronomer Giovanni Hodierna, Messier 37 is the brightest of the three Messier objects found throughout Auriga.  There are more than 500 identified stars with several red giants.  The cluster is about 4500 light years away and extends more than 20 light years from its center.

One month after my initial observation I was able to setup my C11 to image this great cluster.  It is shown below.  If you look closely you can see some of the red giants.

M37, March 19, 2017

Messier Objects - M36

The next few days of posts will be dedicated to logging my observations from my time at the observatory last Friday evening.  The weather was clear all day and I was anticipating a clear evening.  However, as we were driving to the observatory some clouds starting moving in from the West, partially covering the sky.  When the telescope was setup only Orion and Auriga were visible.

In the Explore the Universe certification, M37 was one of the target deep-sky objects located in Auriga.  I decided to go after this before the clouds hindered any observations throughout the evening.  As you can see on the star chart below, M37 is quite close to M36 and M38.  It was located between Beta Tauri (Elnath) the top horn of Taurus' head and Theta Aurigae, the shoulder of Auriga the charioteer.

M36, M37 and M38 Star Chart

I used the finderscope to center Beta Tauri and ensured the telescope was aligned.  I slowly slewed the telescope in the direction of the naked eye star Theta Aurigae while keeping my eye through the finderscope.  Within a few seconds I located a fuzzy patch of light through the finderscope and took a look through the main scope.  I had not found M37 but instead found M36.  I confirmed this observation by moving the scope down across the line between Beta Tauri and Theta Aurigae and found M37.

I went back to M36 to detail some of the characteristics of the Messier object.  M36 is an open cluster with several bright stars but particularly sparse.  I could perhaps view a few dozen stars comprising the entire cluster.  My observation log is provided below.  I did not sketch a picture as I will wait for the opportunity to use my 11" catadioptric telescope to take a long exposure photograph for my records.  The transparency in my record below is low because it was fairly cloudy and thin clouds were covering Auriga at the time of the observation.

M36 Observation Record

In future posts this week I will outline the logs from M37 and M38 which contain more stars than M36.  The 14 day weather forecast is not optimistic for visual astronomy.  It indicates it will be cold, cloudy and snowy.  Hopefully the weather clears up in March and I can get some photographs of these Messier objects.

2017 Week 8: (February 19-25)

The eighth week of the year does not have very much in the way of observing.  The table below shows the only scheduled item of interest.

Date	Event
Feb 20	Saturn 4°S of Moon

An image I took of Saturn on May 3, 2016 is shown below.  I hope to be able to use the high frame rate video camera this year to bring out more detail.

Saturn

Instead of dwelling on the lack of events throughout the week let's discuss what we can see -- The planets.

Mercury is sitting 12° from the Sun in the morning sky and nothing short of a miracle will allow you to see it at this time.  However, on April 1, Mercury will be at its greatest elongation east and visible at its best in the evening sky.  Keep posted for more details around that time so you can get a glimpse of our smallest planet.

Venus is still very bright in the southwestern sky but is starting to get dimmer as it approaches inferior conjunction.  This means it will pass in front of the sun.  As Venus approaches inferior conjunction its phase will continue to wane crescent until it is no longer visible.  If you can steady binoculars you might be able to see the crescent shape.

Earth is quite easy to see at this time of the year especially when the Sun is high in the sky.  If you look down you should be able to see it between your feet.

Mars is dim but very easy to see.  It is just a little south of Venus (up and to the left) by less than 8° (less than the size of your fist held at arms length).

Jupiter is starting to rise earlier in the evening and you will be able to see it just before midnight in the eastern skies.  It will be close to a bright star known as Spica (Alpha Virginis) in the constellation Virgo.  It will be approximately 2.5x brighter than the brightest star in the sky -- Sirius (Alpha Canis Majoris)

Saturn unfortunately is still a morning object pulling itself above the horizon at approximately 5:00am.  

Uranus sits about 5° above Mars and is a binocular object if you have the patience and steady hand.

Neptune is extremely difficult to find at this time even with the finest backyard telescope.  It is heading for its conjunction with the Sun on March 3 and then will reappear in the morning skies later in the month.

The forecast today is for snow and the week is not looking too great.  Time to sit back and do some indoor astronomy!

NOVA Summary: February 2017

The sky was clear most of the day but as we started toward the observatory a large mass of clouds started to move in.  When we arrived, there were a few patches of sky open around Orion and Auriga.  I came prepared with a list of target objects that I wanted to find with my manual scope.  While Auriga was still cloud free I found M37 (19:30), an open cluster of many faint stars.  Five minutes later the bright but sparse M36 (19:35) was logged as it is located very close to M37.  Another twenty minutes passed and I was able to find M38 (19:52), a particularly faint open cluster adjacent to M37.

As the clouds rolled in we had a presentation on logging deep-sky objects with a follow up lesson on finderscopes.  By the end of the lesson the clouds had completely vanished and we were back out on our scopes.  M35 (20:46) in Gemini was found; an open cluster near the North twin's foot.  Our instructor indicated we should try to find M79 in Lepus before it went away for the year.  It was particularly easy as Lepus provided guide stars directly to the only globular cluster I found in the evening (21:03).  After playing around Lepus I decided to head East of Canis Major to find a couple more Messier objects.  M47 (21:08) and M46 (21:16) are about one eyepiece field of view away from each other.  If I had realized how close they were it would not have taken me ten minutes between logging them.

I had the opportunity to use the domed telescope and pointed it at the easy target of M42 -- The Orion Nebula (20:50).  An OIII was on the 31mm Luminos eyepiece and the nebula was amazing.  M43 -- The de Mairan Nebula (20:50) was very obvious under these dark skies and correct filter.  These Messier objects are so close to each other they fit in the same eyepiece field of view.

After my small Messier marathon adventure I spent some time with the binoculars and found a few unnamed open clusters in Cassiopeia.  Kemble's Cascade was found in a southerly direction from Cassiopeia.  When I went back to my telescope I accidentally slew it onto the Double Cluster which provided a great view.  Unfortunately I have not had the opportunity to take a photograph of any of the Messier Objects viewed today but I did take a picture of the Double Cluster back on November 6, 2016 shown below.

Double Cluster (Caldwell 14, NGC869 & NGC884)

My last target was the most difficult.  I decided to try for the comet 45P/Honda-Mrkos-Pajdusakova.  I spent about thirty minutes combing the skies around Coma Berenices with no luck.  Some of the astrophotographers had located the comet and were trying to laser point them to us.  After another fifteen minutes and help from the laser pointers I found a foggy looking blue star.  This was the comet.  It certainly was not an amazing sight but the victory of the long fight to find it was worth it.

Over the next few days I hope to log some of these observations formally and address the intricacies of them.  If you are ever interested in a night out under the stars finding great objects, keep posted for the next NOVA meeting down at the observatory.

Explore the Universe - Gemini

I spent some time mapping the constellation of Gemini.  This is a very popular constellation as it is a member of the zodiac and most people associate it with twins.  It is the astrological symbol for our youngest child.

The mythological background of Gemini is typically quite well known, however, with many interpretations.  The interpretation I follow is Zeus, in the disguise of a swan seeking protection from an Eagle fell into the lap of a Spartan Queen named Leda.  She became pregnant with two eggs, one from Zeus and the other from her husband King Tyndareus.  She later gave birth to Castor, Pollux, Helen and Clytemnestra.  Helen and Pollux were progeny of Zeus, while Castor and Clytemnestra were progeny of Tyndareus.  Helen went on to become abducted by a Trojan Prince named Paris to start the infamous Trojan War.  Castor, being mortal, died.  His brother Pollux was heartbroken and asked Zeus if he could share his own immortality with his brother.  Zeus then transformed them into the constellation Gemini.  They are regarded as the patron of sailors as they visit them as St. Elmo's Fire.  An artistic interpretation of the twin constellation is shown below.

Gemini (Artist Interpretation)

Gemini is a fascinating constellation to observe with any level of optical equipment.  The twin stars, Castor and Pollux are together in the sky forming the heads of twins holding hands in brotherly love.  If you want to grab the binoculars you may have the opportunity to see M35, an open cluster right at the bottom of the northern twin's foot.  I also believe I caught a glimpse of the tenth magnitude NGC object known as the Eskimo Nebula just to the left of Delta Geminorum.  There are several other NGC objects scattered around the constellation.  The Medusa Nebula is at the very southern portion of Gemini, residing several degrees South of Lambda Geminorum.  This may only be available in very large scopes with a high exposure rate imaging device.  I mapped out most of the bright stars using 15x70 binoculars and my map is provided below.

Gemini Observing Record

Take the opportunity to see the sights in the sky, starting with Gemini!

Messier Objects - M42

This blog entry is more of a log book entry this evening.  The Explore the Universe Certificate contains M42 - The Orion Nebula which is a Messier Object.  This is a log of M42 on the Messier log sheets for the Messier Certificate.

A lot of visual astronomy comes down to log book entries if you wish to keep track of your observations.  It is useful to sketch objects you see in the eyepiece as it trains your eye to be keen to details that a casual observer may miss.  I have a set of pencils (HB, H, B, 2B, 4B, 8B) that I use to make sketches.  I am not very good but I hope to improve.  There are members of the Royal Astronomical Society of Canada at our centre that have amazing sketches; I hope to learn from them.  The nebulosity associated with sketches is created by using blending stumps -- tightly rolled up paper tubes the diameter of a pencil.  I scribble a mark on a separate sheet of paper with my 8B pencil and rub the blending stump in it and then apply it to the sketch.  I am still having trouble with my cardinal directions on the sketches since telescopes mirror and/or flip the image around depending on the type of scope used.  I think my best bet is to draw the image and then refer to a star atlas to get my directions straight.  I'll keep trying at the scope though, I shouldn't give up too easily.

Below is the Messier log book entry for the Orion Nebula, also known as M42.

M42 - Orion Nebula Observation Record

This weekend I am hoping to take a long exposure image of the nebula using an OIII filter.  Also, at some point I hope to learn the skill of stacking images together to bring out the best in astrophotographs.  The sky is cloudy this evening so there is not much to look at but I hope to map out Gemini sometime this week.  Keep warm and make sure you have enough wiper washer fluid!

Messier Objects - M45

The Pleiades star cluster has been in our skies for several months and I finally got around to logging it as an observation.  It can be seen as a fuzzy patch of light above and to the West of Taurus.  If you have a simple pair of binoculars the patch stands out as numerous stars.  The cluster contains relatively young hot blue stars held together by gravity.

The name derives from the Ancient Greek verb plein, which means 'to sail'.  The Pleiades were important in ancient seafaring navigation as it marked the beginning of the Spring season when it becomes visible after the vernal equinox.  The 9 brightest stars are named after the seven sisters of Greek mythology (Sterope, Merope, Electra, Maia, Taygeta, Calaeno and Alcyone) along with their parents Atlas and Pleione.

The Pleiades is mentioned throughout the Middle East thousands of years ago and is even mentioned in the Bible (Job 9:9, Job 38:31 and Amos 5:8).

If you are out driving on the road and you see someone driving a Subaru, take note, the logo is the Pleiades.  The Japanese call the cluster Subaru which means 'to unite'.

There is nebulosity associated with the cluster but typically only shows up under the best of conditions.  Your best chance of seeing the nebulosity is to take long exposure photography.  Unfortunately it is a reflection nebula and not an emission nebula so your fancy telescope filters won't help too much.  My observation record for M45 is shown below.  I am not looking forward to sketching more populous open clusters.

M45 Observation Record

Since the cluster is more than 100' in diameter only a wide view telescope and associated eyepiece can really capture it in its entirety.  For this observation I used my 15x70 binoculars with a 4.4° field of view.  However, since it is so wide, it is quite easy to capture using a zoom lens on a camera.  An image I took last night is shown below.

M45 - Pleiades Star Cluster

If you would like to see the cluster with your naked eye a star chart is provided below with the target circled.  If you can find Orion in the southern skies follow the belt to the big red star Aldebaran and continue a little further until you see a fuzzy patch of light.

Pleiades Star Chart

Explore the Universe - Taurus

Taurus is the great bull in the sky that has likely been known since the paleolithic times.  During the Chalcolithic (Copper Age) and the early Bronze Age this constellation marked the location of the Sun during the Spring equinox.  There are many interesting myths associated with Taurus.  In the Epic of Gilgamesh a goddess named Ishtar sends a bull to attack Gilgamesh (likely Orion just to the South).  For many cultures Taurus represented renewal since as the Sun moved into the constellation Spring began.  The Egyptians documented that the Sun would vanquish the bull as a sacrifice to begin the new season.

In Greek Mythology, Zeus took the form of a bull to capture a new mistress -- Europa and carried her across the sea.  This is why the constellation is depicted as just the front end of the bull since its hindquarters are in the water.  A Canadian Inuit myth depicts the brightest star, Aldebaran, as a Polar Bear and the Hyades star cluster around it are dogs fighting it off.  Even Buddhism has a claim that Buddha was born when the Full Moon was in Taurus and his birthday is still celebrated at that time.  An artist's depiction of the great bull is shown below.

Taurus (Artist Interpretation)

Charles Messier, the famous comet hunter, found his first non-comet in Taurus.  He found a fuzzy patch near Zeta Tauri and it became known as M1 - The Crab Nebula.  The Pleiades (M45) is also located in Taurus and is the most visible cluster of stars to the naked eye.  Some people may know the cluster as the Seven Sisters.  Even in heavily light polluted areas you can see the fuzzy patch of stars.  The Hyades star cluster is also located in Taurus in and around the bright red star Aldebaran.  It is interesting to note that Aldebaran is located near the ecliptic and is occulted by the Moon in four year spurts every 20 or so years.  This is actually in progress right now, keep posted for the next occultation of Aldebaran.

Taurus contains many bright stars and is fascinating to look at through binoculars.  The mapping I did is provided below.

Taurus Observation Record

In the picture above you may notice the tight cluster of stars in the right hand corner.  This is the Pleiades star cluster, also known as Messier 45.  I took an image of it below.

Pleiades Star Cluster (M45)

The Hyades is located just South of the Pleiades and a picture is provided below.  Notice the 'dogs' all attacking the big polar bear at the top of the picture.

Hyades Star Cluster

As I was trying to get a good image of the Hyades a satellite quickly flew through my view and is depicted as a string of light over the exposure of the photo.

Satellite through the Hyades

As the weather gets warmer and the skies get clearer I hope you have the opportunity to take a closer look at Taurus!

The Tides

Introduction

Anyone who has ever been to the ocean has witnessed high tide and low tide.  What causes this phenomenon?  How does the phase of the Moon affect the size of the tides?  I've outlined some of the basic facts below.  Complications such as the slowing of the Earth's rotation, fluid distribution, coastline topography and tidal acceleration are left out of this general discussion.

Basic Tides

The Moon has mass and therefore exerts a gravitational force on another object proportional to the inverse square of the distance between the two objects.  This essentially means the closer you are to the Moon the larger the force of gravity.  When the Moon is directly overhead it exerts the strongest gravitational force at the location directly underneath.  At the same time, the gravitational force it has on the other side of the Earth(nearly 13,000km further away) will be at its weakest.  This gravitational force causes fluids (atmosphere and water) to seemingly be pulled towards the Moon when it is directly overhead causing a high tide.  Low tide occurs at the location on Earth 90° from the Moon.

**It is interesting to note a complication that high tide does not occur directly under the Moon due to the lag in the water flow.  This phenomenon causes the recession of the Moon and the slowing of the Earth's rotation.**

The Bay of Fundy in Nova Scotia is known to have the largest tides in the World due to its geometry and water distribution.  An image is shown below.

Bay of Fundy, Low Tide (left), High Tide (right)

Second High Tide in a Day

So why is there also high tide on the other side of the Earth at the same time, I thought the force was weaker there?  That is a good question.  There are many explanations in cyberspace that are significantly confusing.  I'll give it a try.  The basic idea is that the gravitational force on other parts of the Earth are stronger than at the point furthest from the Moon.  This causes the Earth to seemingly pull away from the regions of lesser force causing it to bulge out at either end.

How Phase Affects Magnitude of High Tide

Let's get into something easier to understand -- how the phase of the Moon affects the size of the tides.  The Moon is not the only strong gravitational source in the Earth's vicinity.  The Sun is much larger than the Moon but much further away.  If you work out the calculations, the tidal force from the Sun is about 50% that of the Moon.

During a New Moon the Sun and Moon are on the same side of the Earth and add their gravity to create large tides.  This is what is called a spring tide.  Don't confuse spring tide with the season it is supposed to mean that the tide springs ahead more at this time.  The same thing occurs when there is a Full Moon whereby the Sun and Moon are again in a line except on opposite sides of the Earth.

When the Moon is at First Quarter or Last Quarter it is at the point in its orbit 90° away from the Sun.  This has the Sun and Moon pulling in different directions cancelling out each other's effects.  High tides will be noticeably lower and it is called a neap tide.

An image borrowed from Wikipedia describes this process.

Spring and Neap Tides

Perigean Tides

Since the Moon orbits the Earth in an ellipse it can be closer or further from the Earth at a given time in its orbit.  This is the same phenomenon that causes what are known as 'Supermoons' -- the perigee (closest approach) aligns with a Full Moon.  We discussed earlier than the force of gravity is dependent on the distance between the two objects.  When a Full Moon or New Moon occur at perigee there will be higher high tides and lower low tides.  Alternatively, when a Full Moon or New Moon occur at apogee (furthest approach) the tides will be smaller.

Other Considerations

Since the Earth rotates in the same direction the Moon orbits, the time between high tides is about 12.5 hours.  It takes the Moon approximately 24.5-25 hours to be at the same spot above the Earth. This is the same idea as the minute hand on a watch meeting up with the hour hand every one hour five minutes and twenty seven seconds.

Light Pollution: A Growing Urban Problem

Light pollution is one of the most disruptive man-made influences on astronomy and our ecosystem.  Light pollution is known to hinder and change food webs allowing light tolerant species to out-compete specific nocturnal species.  Light pollution can affect the human sleep cycle and cause undue stress and increase the frequency of headaches.  Chronobiologists (remember de Mairan of M43 fame) have been researching this phenomenon more intensively lately and have disturbing results.

Ecological damage aside, light pollution has a major negative effect on astronomy.  Misdirected light can cause significant sky glow and drown out any hope of seeing deep-sky phenomena.  A lot of people will grow up without ever seeing the Milky Way.  Lots of urban areas overuse light for commercial benefits at a great cost to the natural environment.

Below is an image I took in February 2017 showcasing the Calgary Auto Mall and Deerfoot Meadows drowning out all but two bright planets: Venus and Mars.

Venus and Mars above significant light pollution

Astronomers have used several methods to fight against light pollution but it is a losing battle.  Light pollution filters that filter out common urban light spectra can only do so much.  Education is perhaps the strongest way to change urban sensibilities.  Light should be directed to the ground and not wasted by directing it in all directions or, even worse, into the sky.  Thanks Las Vegas.  If you see examples of responsible or irresponsible urban lighting please submit pictures so they can be displayed on our Facebook page.  If you would like to follow the Royal Astronomical Society's Light Pollution Twitter feed check it out: @RASC_LPA.

The Calgary Centre's Webpage is given below:

http://calgary.rasc.ca/lp/index.html

Even driving 20 minutes outside of the city to the observatory makes a world of difference.  You can probably see an entire stellar magnitude dimmer away from the city.  If you would like to see how much light pollution there is in your jurisdiction check out the map below.

Light Pollution Map

2017 Week 7: (February 12-18)

This upcoming week has some significant events that you don’t want to miss.  Starting on Monday the zodiacal light should be visible from dark skies for the next several weeks.  Look to the western skies soon after sunset and see if you can see a conical light emanating from the horizon.  Mars and Venus are lined up to be inside this cone.  We are going to take a trip outside of town to some dark skies to see if we can see it this year.  For more information about Zodiacal Light please see the post from last Saturday linked below.

Zodiacal Light

Another exciting thing happening this week is associated with the planet Venus.  Venus will be at its greatest brilliancy Thursday evening and Friday morning.  Even though it is a waning crescent, approximately one-third illuminated, it will be large and bright.  If you are at a dark site, you may be able to see your shadow cast across the ground from the light of Venus.

**Don't forget the penumbral lunar eclipse tonight!  At Moon rise (5:44pm) the Moon will appear slightly shaded as it transits through the outer shadow of the Earth!  Full details linked below.**

Penumbral Lunar Eclipse Information

As typical in most months, Jupiter will be aligned with the Moon Wednesday evening at a separation of 3°.  This is close enough to fit in a typical binocular field of view.  The Last Quarter Moon will appear on Saturday on its way to fading out to start a new lunar cycle.  The full astronomical schedule for next week is below.

Date	Event
Feb 13	Zodiacal Light strongly visible in western sky for two weeks
Feb 15	Jupiter 3°S of Moon
Feb 17	Jupiter at Aphelion
Feb 17	Venus at greatest brilliancy
Feb 18	Last Quarter
Feb 18	Moon at Apogee
Feb 18	Asteroid Irene at opposition

Interestingly, the asteroid Irene will be at opposition and at its brightest.  However, it will be magnitude 9.0 and you’ll be lucky to catch it in a pair of nice binoculars.  It will be more than 3° from the naked eye Zeta Leonis in the constellation Leo.  Attempting a telescope find will be difficult, however if you wish to try your luck a star chart is provided below with a binocular field of view circled.

Irene Star Chart

The weather is starting to warm up and the skies are clearing.  There will be plenty of opportunities to look up and see some of your favourite planets!  Look for Jupiter moving to the southwestern sky just before sunrise!

Transparency and Seeing

The weather has a significant impact on astronomy no matter where on Earth you are located.  Two vital meteorological conditions that hinder astronomers is transparency and seeing.

Seeing is essentially the amount of disturbance caused by the atmosphere at a given time.  Sometimes you may notice stars twinkle more on one night than another.  Twinkly stars occur during times of bad seeing.  When looking at the Moon through a telescope you may see it shaking or shuddering as the atmosphere is turbulent.  When the seeing is considered to be good the Moon and stars will be still and objects will have higher resolution.  Typically the seeing worsens as the light from the sky traverses more of the atmosphere.  This is the reason why objects appearing on the horizon don't show up as well in a telescope or binoculars.

Planets are notoriously affected by bad seeing.  Astrophotographers have an interesting way around this problem.  A high frame rate video camera is used to capture approximately 30 seconds of footage of a planet through a telescope.  The frames with good seeing during that 30 second period are kept, while the bad frames are filtered out.  This produces amazing images of planets taken from places as simple as your backyard.  When the weather gets better I will try out my 100 fps camera on Venus and Jupiter to test this method out.

There are some things you can do to improve your local seeing.

1. Leave your telescope outside so that it cools down to the ambient temperature.  Temperature differentials cause air flow which, in turn, leads to poor seeing.
2. Observe on grass.  Concrete tends to absorb and radiate more heat causing additional temperature differentials.
3. Observe on a platform to avoid low to the ground air currents.

The other important thing to note before hauling out the telescope is transparency.  Transparency is simply how clear the night sky is.  Water vapor(clouds), dust particles, smog and smoke all negatively affect the transparency.  Some of these scatter the light making the background lighter and the objective object dimmer.  In bad conditions the sky may appear completely opaque disallowing any chance for visual astronomy.

Consider an object underwater at a lake. The amount of ripples relates to the seeing and the amount of dirt and dust in the way relates to the transparency.

Unfortunately for astronomy a lot of the time good transparency may mean bad seeing and vice-versa.  After a storm the rain has cleared away a lot of the pollution from the skies giving good transparency.  However, the wind currents in the vicinity will provide poor seeing.  Thus two simple ideas must be shared.

1. Good seeing, poor transparency - Planets and the Moon make great targets
2. Poor seeing, good transparency - Deep-sky objects make great targets

An example of comparative seeing is shown below in an image taken by the well-known astrophotographer Damian Peach.

Comparative seeing of Jupiter

As always, it is always good to check the forecast before heading out observing.  A great site for Calgary is linked below.  It provides the cloud cover, transparency, seeing, darkness, wind, temperature and humidity.

http://www.cleardarksky.com/c/Calgarykey.html?1

Telescopes - What should I look for?

There are many aspects about a telescope that should be considered before purchasing one.  This post will be an introductory primer to some of these considerations.

Let's get some terms out the way first.

Aperture - This is the size of the mirror or lens that collects the light from the sky.

Focal Length - This is the length the light has to travel in the telescope before being focused at the eyepiece.

Focal Ratio - This is the focal length divided by the aperture.

Reflector - This type of telescope collects light on a parabolic mirror and reflects it back toward a secondary mirror which delivers the light to an eyepiece.

Refractor - This type of telescope collects light with a lens which, in turn, delivers the light to an eyepiece further down the tube.

Catadioptric - This is essentially a composite telescope that collects the light with a lens and uses interior mirrors to bring the light to the eyepiece at the other end of the optical tube.

There are many different builds of telescopes but the basic types are listed above.  In later blogs individual builds of telescopes will be investigated more thoroughly.

A refractor tends to have very clear images as light travels through less optical material.  However, it focuses different colours of light at different points causing chromatic aberration; distorting the image.  This can be corrected by using a doublet or triplet apochromatic telescope.  These telescopes are very expensive per inch of aperture.  However, a low aperture apo refractor is perfect for planets and large expanse nebulae.  On a motorized mount you will be able to get amazing photographs.

A catadioptric telescope tends to have a very long focal length and comes in a compact optical tube.  This is very handy for transportation as it can fit in the trunk of a car quite easily.  The price range is moderate per inch of aperture so it might be a good advanced scope to invest in.  The planets will be amazing and deep-sky treasures will be yours for the taking.  The focal ratio is typically quite high (f/10 etc.) so you will have to take longer exposures if you are interested in astrophotography.  A focal reducer can be added to take it down to f/7 or so to alleviate this issue slightly.

The first telescope I started to work with consistently is an 8" Reflector on a Dobsonian Mount.  A Dobsonian mount is essentially an alt-azimuth mounted telescope that supports rotating the optical tube on two axes, the azimuth(side to side) and altitude(up and down).  A image of this is shown below.

8" Reflector with Dobsonian Mount

The aperture size determines how much light is gathered by the telescope.  The higher the aperture, the more light that is gathered.  With greater light gathering ability you will be able to see fainter objects.  The focal length is an important factor in determining how much magnification you can get out of your telescope.  The magnification is simply calculated by dividing the focal length of the telescope by the focal length of the eyepiece.  The higher the focal length of the telescope the more magnification you can get with each eyepiece.  For more information about eyepieces please see my previous post linked below.

http://simonjastronomy.blogspot.com/2017/01/nova-summary-january-2017.html

There are several warnings about going out to get the highest aperture, longest focal length telescope.

1. The higher the aperture the heavier the telescope.  You will not use a telescope that you can not carry conveniently.  It will collect dust around the house.
2. Magnification can only take you so far.  If the magnification is too high you will be magnifying the atmospheric disturbances and will likely see nothing but blurry objects.  Do not trust shopping mall telescopes that say they will give you 500x.  You will see nothing but blurry light.

An 8" telescope with a 1200mm focal length is a medium range telescope that can be used to find all the deep-sky Messier Objects and, at the same time, have great views of the planets.  The Dobsonian mount is very easily transported and offers the most affordable telescope per inch of aperture.  I can setup and take down my telescope in less than 30 seconds.  The drawback to this mount is that it does not track automatically.  You will not be able to take long exposure photographs using it.  As the Earth rotates you will get star trails in your images.

Several people have asked if a telescope can be used for terrestrial viewing.  They certainly can.  I've pointed my telescope at the mountains and had great views.  Whatever you do DON'T POINT IT AT THE SUN.  You will destroy your eyes and your telescope.  There are ways to do this safely as outlined in a previous blog post listed below.

http://simonjastronomy.blogspot.com/2017/01/explore-universe-sunspots.html

If you are considering purchasing a telescope I would be more than happy to offer my advice and point you in the direction of some expert dealers.

Astronomy - The Gateway Science

At one point or another everyone has had the opportunity to gaze up at the wondrous night sky.  The Moon, the stars, the planets and the colourful aurora have illuminated the eyes of so many of us.  As the the great expanse of the heavens are opened to us we can almost feel our mind and soul expanding to keep up.  Philosophical questions come to mind with the answers written on the nearly infinite chalkboard above.  We just need to learn to read it.

Curious children who are exposed to science at a young age are typically more engaged at school with a passion to learn new things.  It sparked an interest in me so many years ago and I went on to become trained as a theoretical quantum physicist.

A common theme of this blog is that astronomy is a science for all levels of experience.  Whether you are a young child or a seasoned astronomer there will always be something to fascinate the mind.  There are no prerequisites or instruments required.  All you have to do is look up from the front steps of your home and a wealth of knowledge is there for the taking.

This website and Facebook page are devoted to providing a guide to the knowledge that can be derived from the skies in our very own communities.

The study of astronomy is co-dependent on almost every field of science.  As such, it is referred to as the gateway science.  An early interest in astronomy can branch off to many different scientific fields of study.  A few common examples are shown below, but certainly not limited to:

• Physics - Orbital motion, Relativity
• Chemistry - Nuclear fusion, atomic spectra
• Biology - Astrobiology, Extraterrestrial life
• Geology - Planetary formation and isotopic analyses

Our focus is "Local Amateur Astronomy for Everyone".  No matter what your locality or your experience level, there will be astronomy for you.  Our mission statement is simply "Look Up".  This is not a business; it is just an informational site based on my passion for science.  It is a safe place where we can all get our nerd on and enjoy the infinite wonders above us.

Whether you are looking for advice on buying a telescope or wanting to know the name of the constellation staring down at you, this is the place to be.  Special astronomical events that will take place in the coming days and weeks will be forefront so you won't miss out.

What is a Planetary Nebula?

There are several Messier and Caldwell objects classified as a planetary nebula.  Even though the name suggests they are in reference to a planetary phenomenon, the truth is quite different.  A planetary nebula is a giant ball of gas that has been ejected from a very old star.  The ejecta thrown off by the star is intensely heated by radiation from the core of the star causing the gas to glow and emit different wavelengths of light -- different colours.  The ejection from a spherically symmetric star causes the nebula to be basically round in shape.  This is how it received the name 'planetary'.  Astronomers thought they looked planet shaped and that they were condensing into planets.

A great thing about the ejection of matter from stars is that it seeds the galaxy with heavier elements formed by nuclear fusion in stars.  If you look closely through a larger backyard telescope you may see the core of the original star that caused the nebula to form.  At one time or another I've witnessed the magnitude 14.8 white dwarf stars at the center of the Ring Nebula in photographs I have taken at high exposure times.  These white dwarfs are shining brightly to illuminate the surrounding gas.

Atoms and ions emit radiation when they are energized by incoming radiation.  They emit only certain frequencies of radiation corresponding to different colours of the electromagnetic spectrum.  A doubly ionized oxygen ion is found in abundance in planetary nebula and emits a certain spectra of light consisting of three emission lines around 500nm.  This ion is also known as the (O III).  Telescope stores stock O III filters that you can use on your eyepiece to allow the transmission of these lines.  This allows an amazing amount of contrast of the nebula from the surrounding light pollution and stellar phenomena.

One of my favourite planetary nebulae is the Ring Nebula.  It is located approximately halfway between Beta and Gamma Lyrae (the bottom of the Lyre).  It is an extremely easy telescopic target to find and view.  In dark skies you may even see it through a good set of binoculars.  An image I took in Fall 2016 from my backyard is shown below.

M57 - Ring Nebula

As stated previously, the Ring Nebula is very easy to find in a telescope.  A star chart is provided below of the constellation Lyra with M57 highlighed.

M57 in Lyra

The next time you are at a public star night, ask to see a planetary nebula and see what you think it looks like!

Comet Alert: 2P/Encke

As February grows older a comet grows brighter.  2P/Encke, also known as Encke's Comet will be visible in our skies with a telescope or a pair of binoculars.  It is a 4.8km wide comet first discovered in 1786 by Pierre Mechain.  More than 30 years later a German astronomer named Johann Franz Encke computed its orbit and, subsequently, had his name immortalized.  The naming convention of '2P' indicates the comet was the 2nd Periodic comet discovered.  The first periodic comet being the more famous 1P/Halley.

The debris left from the comet is known to cause the northern and southern Taurid meteor showers throughout the autumnal months.

2P/Encke will peak in magnitude around 3.5 which is the brightness of a lot of naked eye stars seen from a light polluted city.  However, it reaches this magnitude as it approaches the Sun and the twilight will completely washout any hope of seeing it.  A NASA image of the comet taken from a Mercury orbiter caught this great image in 2013.

2P/Encke

However, if you have a pair of binoculars or a telescope I have some tips on finding this comet in February.  On February 23 at 19:30 the star chart is provided below.  2P/Encke will be approximately 7° southwest of Venus and approximately 2° northeast of Omega Piscium.  This would put the comet about 2 binocular fields of view away from Venus and in the same field of view as Omega Piscium.  It will be magnitude 6.7, unable to be accessed by the naked eye but certainly possible in a simple pair of binoculars.

2P/Encke Star Chart

Please click below for a downloadable, printable version of the star chart.

2P/Encke Printable Star Chart

As the month grows older I will update my progress on hunting down the comet.  If I am able to find it I will detail the procedure in a special blog post so you may have the opportunity to find it yourself.  There will be likely no opportunity to observe the skies this week as the weather deteriorates significantly below seasonal for the next 5 days.  Stay warm and don't look up lest you get snow in your eyes.

What is Zodiacal Light?

An interesting phenomenon that will be visible this month is the zodiacal light.  Zodiacal light is a cone shaped glow extending up from the sun after twilight.  The best time to see it is late winter in the evening sky and autumn in the morning sky.  It is caused by the Sun's light being scattered by dust in the solar system.  It is called 'zodiacal' because the glow follows the path of the zodiacal constellations along what is called the ecliptic.  If you are in dark skies, look toward the west for the zodiacal light in line with Venus and Mars.  An image borrowed from wikipedia is shown below.

Zodiacal Light

If you would like a good introduction, the European Southern Observatory has a great video below.

Zodiacal Light (ESO)

A news article from 2015 on space.com describes how to see this phenomenon.

http://www.space.com/28482-zodiacal-light-visibility-space-dust.html

It is very difficult to see so I wish you great luck.  If you find yourself away from city lights at sunset this month, take the opportunity to step out and scan the western horizon near Venus and Mars.  This phenomenon is also an observation requirement for the Explore the Universe certificate.  I hope to have the opportunity to find a dark site to see this amazing light!

2017 Week 6: (February 5-11)

This week we will be treated to a penumbral lunar eclipse!  A lunar eclipse occurs when the Earth is between the Sun and the Moon and the plane of the Earth's shadow is in line with the Moon.  This causes the Moon to become darker as though some big object stepped between the Sun and the Moon.  A shadow has several parts associated with it.  The deep dark part of a shadow is known as the 'Umbra' and the lighter fuzzy part is known as the 'Penumbra'.  In Latin umbra means 'shadow' and penumbra means 'almost shadow'.

Penumbral Lunar Eclipse

In the case this week the penumbral part of the Earth's shadow will pass over the Moon.  Some astute observers may notice the Moon become a light red colour.  The red colour comes from the Earth's atmosphere scattering the blue part of the light spectrum away while leaving the red light to transmit through.  This is the same reason sunrises and sunsets appear to be an orange/red colour.  The Moon is red because the red light part of the spectrum from the Sun is transmitted and refracted through the Earth's atmosphere to the Moon.  It is almost like a lens that transmits only a certain frequency of light.

A penumbral eclipse is sometimes difficult to notice as only the outside of the Earth's shadow passes across the face of the Moon.  For more information see the article in Sky and Telescope below.

http://www.skyandtelescope.com/astronomy-news/feb-10th-penumbral-lunar-eclipse/

For observers in Calgary the eclipse will have already started when the Moon rises at 5:43pm and will continue until 7:53pm.  For the best view find a location where you can see the eastern horizon during the given times.  Other astronomical events for the week are listed below.

Date	Event
Feb 5	Aldebaran 0.2°S of Moon
Feb 6	Moon at Perigee
Feb 6	Jupiter Stationary
Feb 10	Penumbral Lunar Eclipse 3:34pm - 7:53pm
Feb 10	Full Moon
Feb 11	Regulus 0.8°N of Moon

It is interesting to note that Jupiter is stationary to the background stars and begins what is known as its retrograde motion on February 6.  Retrograde motion is caused by the Earth completing its orbit in a shorter amount of time compared to the outer planets.  A useful video on this phenomenon provided by the University of Nebraska-Lincoln is linked below.

Retrograde Motion

The forecast at the time of writing this calls for extreme cold and snow until Wednesday.  The weather starts to come back to seasonal conditions for Thursday and Friday, just in time for the lunar eclipse.  Stay warm this week and prepare for our first eclipse of the year.