2017 Week 10: (March 5-11)

The next week there is not too much happening in the sky.  The Moon will reach its first quarter at 4:30 in the morning on Sunday.  The only really neat observation will occur on Saturday the 10th.  The brightest star in Leo will be visible extremely close to the Moon.  You will be able to see them in the same moderate angle telescopic field of view at 48'.   The chart below highlights this next week.

Date	Event
Mar 5	First Quarter
Mar 6	Mercury at Superior Conjunction
Mar 10	Regulus 0.8°N of Moon

Mercury will be at what is known as superior conjunction.  This happens when an inferior planet (planet inside Earth's orbit (Mercury or Venus)) lies on the opposite side of the Sun.  It is the point where the inferior planet is lined up behind(typically above or below) the Sun as viewed from the Earth.  When a planet is at inferior conjunction it lines up in front of the Sun.  The orbital plane of the planet usually takes it above or below the Sun as it is in conjunction.  However, on May 9, 2016, Mercury was at inferior conjunction right in front of the Sun.  I used a solar filter on my 8" telescope and actually saw Mercury pass across the face of the Sun.  This is a very rare event.  It happens around a dozen times a century for Mercury and around twice a century for Venus.  Fortunately the next transit of Mercury is coming up on November 11 starting at sunrise and continuing for three and a quarter hours.  If you are waiting for the next transit of Venus partly visible from Calgary, it will occur late in the fall on December 8, 2125.  The next transit of Venus fully visible from Calgary will be late in the 25th century on June 12, 2490.  Don't miss it.  Mark it on your calendar.

An image from the May 9, 2016 Mercury transit is shown below.

Transit of Mercury, Image credit: NASA's Goddard Space Flight Center/SDO/Genna Duberstein

The weather forecast for the week is not too optimistic.  The 2016-2017 winter trend of below average temperatures continues with little respite in sight.  Hopefully the clouds will stay away and you will be able to see the winter constellations before they set for the year.

Explore the Universe - Canis Major

Canis Major cruises across our southern sky throughout the winter.  The brightest star in the constellation is actually the brightest star (besides our own) that can be seen from Earth.  Alpha Canis Majoris is also known as Sirius, commonly called The Dog Star.  Several constellations that are visible from Rio de Janeiro are located on Brazil's flag and Canis Major is one of them.  The five brightest stars are present on the flag.  These stars also represent five states within the country.  The link below will take you to the full explanation of the stars located on the Brazilian flag.

https://en.wikipedia.org/wiki/Flag_of_Brazil#Stars

Canis Major is also known to contain one of the largest stars ever recorded.  VY Canis Majoris has a radius 1420 times that of our Sun.  If this star were the center of our solar system it would stretch out beyond the orbit of Jupiter.  A size comparison of stars is shown in an image below.

Planet and Star Size Comparison

The civilizations of ancient Mesopotamia believed Sirius was an arrow and the rest of the constellation was a bow.  The arrow was aimed right for the great Hunter -- Orion.  A particularly interesting Greek Myth has Laelaps, a mythological dog that always caught its prey, square off against a Teumessian Fox, a gigantic fox that can never be caught.  A paradox was created by their mutually excluding mythological abilities.  Zeus was perplexed by the paradox and decided to turn them to stone and cast them into the sky as Canis Major (Laelaps) and Canis Minor (Teumessian Fox).  The famous Greek poets simply refer to Canis Major as the hunting dog of Orion that assists in hunting Lepus the hare and Taurus the bull.

Canis Major and Lepus (Artist Interpretation)

This evening I mapped the constellation with binoculars.  Unfortunately, due to the southerly declination of the constellation, the atmosphere hazed out some of the dimmer stars.  A house was also in my way on the southern parts of the constellation.  With some maneuvering I was able to nab Kappa and Lambda Canis Majoris.  The mapping is provided below.

Canis Major Observing Record

As notes in the image above, Canis Major contains one Messier object.  M41 is an open cluster located approximately 4°S of Sirius.  Even with the light pollution, atmosphere and an ill placed house I was able to see the cluster through my binoculars.


Clear Skies and hopefully Warm Weather!

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.