2017 Week 30: (July 23-29)

The final week of July has come and with it the last lunar cycle before the great solar eclipse.  There are several conjunctions happening throughout this week including the innermost planet Mercury.  If you have a view of the western horizon you might be able to pick Mercury out of the twilight as it will be less than a degree South of the Moon.  It will be quite close to the alpha star in Leo and shining twice as bright before you go to bed on the 25th.

Date	Event
July 23	New Moon
July 25	Mercury 0.9°S of Moon
July 25	Regulus 0.07°S of Moon
July 26	Mercury 1.1°S of Regulus
July 26	Mars in conjunction with the Sun
July 27	Southern Delta Aquariids Peak
July 28	Jupiter 3°S of Moon

July 26 also has Mars in conjunction with the Sun.  This means Mars will be tucking in behind the Sun and will start peeking out in the following months.  On July 27th in 2018 Mars will be at opposition, its closest since 2003.  However, for higher northern hemisphere observers it will be difficult to see properly.  It will be at nearly -26° declination.  This is lower than Saturn currently sits.  The atmosphere will give us bad seeing which will make it quite difficult for imaging.

The Southern Delta Aquariid meteor shower will also peak this week.  The radiant is, obviously, Delta Aquarii in the southern reaches of Aquarius.  Your best bet to see them will be between Thursday and Friday.  Look South in the middle of the night and catch perhaps 20 meteors per hour at their best.  An image of Aquarius with Delta Aquarii circled is shown below.  It is located at the bottom of the flow of water from the water bearer's flask.

Aquarius and Delta Aquarii

Jupiter is starting to go down with the twilight in the West and will be close to the Moon Friday evening.  If you're hoping to catch it through a telescope you better get your observing in before the fine details get swallowed in the atmosphere!

Astronomical twilight is finally over and Calgary can have some real night for the first time since the end of May.  This will be a great time to get prepared for another season of great observing!

2017 Week 29: (July 16-22)

This Summer has proven rotten for anything good in the sky to observe.  The 29th week of the year does not have anything too special.  The last quarter Moon occurs tomorrow if anyone is awake in the early morning before sunrise to see it shine brightly in the sky.  Aldebaran will be very close to the Moon a few nights later closer to sunrise.

Date	Event
July 16	Last Quarter
July 19	Aldebaran 0.4°S of Moon
July 20	Venus 3°N of Moon

If you like viewing Venus you can see it in the morning sky a few hours before sunrise.  It will be quite close to the waning crescent moon on July 20.  Soon we will have the July new moon which is exactly one lunar cycle before the great solar eclipse on August 21.

There are many interesting constellations up in the sky during the early Summer.  Hercules stands bright at our zenith and, for the careful observer, you might be able to catch M13 in all its great glory.

M13

The twlight is still killing early evening observing but if you like staying up past midnight you'll be able to view the stars in cool comfort after the bugs have gone to bed.

Please catch Jupiter as it plunges into the sunset after another season of great evening observing.  Saturn will be directly south with nearby Antares shining brightly to the west of the ringed planet.

Good luck observing this week and watch closely for some Summer constellation profiles I hope to post throughout the next couple weeks!

2017 Week 28: (July 9-15)

It is Stampede week in Calgary and we've been hit with a heat wave.  Hopefully you'll take some time in the evening to cool down in your backyard and look at the sky.  However, there isn't much to see as far as significant astronomical events.

Date	Event
July 9	Mercury 0.04°N of M44 (Beehive Cluster)
July 13	Neptune 0.9°N of Moon

The Moon will be full this evening and, along with the heat, will contribute to insomnia across southern Alberta.

If you haven't caught Jupiter yet this year I would encourage you to look to the southwest.  It will be dipping down into the twilight soon and the Earth's atmosphere will destroy any good seeing for the year.  Saturn will be in a great position as it can be seen in the southern sky.  It will be at an altitude of approximately 17° above the horizon just before midnight.  It will not be for a few years before Saturn will be higher in the sky away from the poor seeing that comes being so low.  Saturn's rings are pretty much tilted to their maximum and any small telescope will be able to make them out.  If you are lucky and have moments of good seeing you may be able to see the divisions among the rings.

The great solar eclipse is almost a month away so you should be thinking about preparing for it.

Solar Eclipse

If you are to travel from Calgary your quickest driving route will be Oregon, Idaho, or Wyoming.  Below are some maps of the route of totality.

Oregon Totality

Idaho Totality

Wyoming Totality

Calgary will see a partial eclipse with the New Moon covering approximately 77-78% of the face of the Sun.  It will be dangerous to look at the Sun without proper protection during all times of the eclipse from Calgary.  To view with your naked eye you should have certified solar glasses and, even then, do not stare at the Sun for long periods of time.  If you are interested in a pair of these glasses please get in touch with me through my facebook page below.

https://www.facebook.com/simonjastronomy/

2017 Week 27: (July 2-8)

The first week of July has begun and the Sun will start spending less time in the sky as the days progress.  There are only a few sights in the sky this week but perhaps worth checking out.

Date	Event
July 2	Juno at opposition
July 3	Earth at aphelion
July 7	Saturn 3°S of Moon

If you are a telescope user the asteroid Juno will reach opposition on July 2.  It is, however, an unfavorable opposition and will only reach magnitude 9.8.  Good luck if you try to scope it out.

The Earth will reach aphelion the next day which means it will be at its furthest point away from the Sun in its orbit.  This may seem counter intuitive to residents of the Northern Hemisphere.  The heat of summer occurs while the Earth is at its furthest from the Sun?  That is true, it is the tilt of the Earth that affects the seasons, not the proximity to our home star.  Perihelion occurs around January 3 each year and the Earth is at its closest in the elliptical orbit.

Later in the week Saturn will appear 3° South of the Moon.  Saturn has been visible in the early evening skies for a few weeks now if you look toward the southeast.  Observers with telescopes should try to find Saturn while the Sun is still above the horizon using the Moon as a guide.  Last night Jupiter was only 2.5° away from the Moon and I was able to catch it in my telescope more than 2 hours before sunset.  The equatorial bands and great red spot were clearly visible against the backdrop of the blue sky.

Jupiter

The Moon's phase will be between the first quarter and full which means it is easy to see in the early evening and has amazing features that can be seen with just a simple pair of binoculars.

Lunar Impact Craters Visible from 8-9 Day Old Moon

The ice giants in the outer solar system are starting to rise nearer to midnight and will make challenging targets for amateur astronomers.  I can promise that finding Neptune or Uranus with a manual scope is quite rewarding!

2017 Week 26: (June 25-July 1)

This upcoming week will mark the halfway point of the year.  The double shadow transits of Jupiter's moons are done for the year which offered a great sight over the past 6 weeks.  The waxing crescent Moon appears this weekend to mark Eid al-Fitr for Muslims throughout the world.

Waxing Crescent Moon

The chart below highlights the significant events that can be seen in the sky throughout the week.

Date	Event
June 27	Regulus 0.03°N of Moon
June 30	First Quarter
July 1	Jupiter 3°S of Moon

Unfortunately there are not many exciting things happening throughout the week.  The bright breast bone star of Leo will be tucked in right next to the Moon this Tuesday evening.  Closer to the weekend every astronomer's favourite phase of first quarter will occur on Canada Day eve.  The Moon then moves over to be in conjunction with Jupiter the next day as we celebrate our nation's birthday.

We are still stuck in a rut for twilight over the next few weeks but the dark skies are on their way back in.  The Summer Triangle will be shining over our heads and we can pick out some great open clusters and planetary nebulae.  The Milky Way will make a great visual sight if you can get away from the city far enough to have pristine unpolluted skies.  The Rothney Astrophysical Observatory will host 6 nights of Milky Way observing in July and August.  Information for the July nights is given below.

https://ucalgary.ca/rao/event/2017-07-20/milky-way-nights-july-20-2017

I hope you have the opportunity to come out to see the sky.  Many people born today may never get to see the Milky Way due to the growing light pollution found throughout the world.  I am hoping to get a picture of the Milky Way this year but I'm not sure if my camera is quite up to it!  Good luck observing Jupiter and Saturn in the southern skies this week!

What is Twilight?

Calgary does not have true night between the third week of May and the third week of July.  The best we can manage between those times is astronomical twilight.  What are the different definitions of twilight?

There are three types of twilight defined below.

Civil Twilight
The Sun is located less than 6° below the horizon.  Civil Dawn/Dusk happens when the geometric center of the Sun is exactly at 6° below the horizon.

Nautical Twilight
The Sun is located between 12° and 6° below the horizon.  Nautical Dawn/Dusk happens when the geometric center of the Sun is exactly at 12° below the horizon.

Astronomical Twilight
The Sun is located between 18° and 12° below the horizon.  Astronomical Dawk/Dusk happens when the geometric center of the Sun is exactly 18° below the horizon.

When the Sun is 18° below the horizon it is officially Night.

It is well known that locations near the poles may experience days where there is no twilight and days that are completely night.

Many laws are incorporated in relation to civil twilight regarding driving, flying and even burglary.  Venus is typically visible during this time.  Nautical twilight is generally the time when sailors may use the stars to take measurements for manual navigation.  Once astronomical twilight is over and night arrives you will be able to see as many objects in the sky as your eyes and light pollution permits.  Deep-sky objects are able to be resolved and astronomers are happy.

To determine when these specific types of twilight occur in Calgary the following website is useful:

https://www.timeanddate.com/sun/canada/calgary

In the dead of Winter we get a whopping 12 hours of night.  However, the temperature and snow generally limit the joy of astronomy.  My favourite months for astronomy are March, April, September and October.  They offer a good balance of darkness and tolerable weather.

The image of a waxing crescent Moon and Venus below was taken Fall 2016 during nautical twilight.

Moon and Venus (Nautical Twilight)

2017 Week 25: (June 18-24)

This upcoming week marks the first day of Summer as discussed in the previous post about the solstice.  In the early morning sky before sunrise you will be able to catch Venus shining above everything in the sky except for the Moon.  Venus and the Moon will fit into the same binocular field this upcoming Tuesday so be sure to check it out.

Date	Event
June 20	Venus 2°N of Moon
June 20	Solstice
June 24	Super New Moon

10:24pm on the evening of Tuesday, June 20 will mark the beginning of Summer as the Sun will be observed to start decreasing in declination.  An interesting event happens next Saturday.  There will be a supermoon.  It is not advertised throughout the media because it is a New Moon supermoon.  You will not see a majestic bright rock in the sky, in fact you will not see anything.  However, since the Moon is at perigee (closest position to Earth in its elliptical orbit) at a New Moon the tides will likely be larger than normal.

There are other great sights to amaze you in the sky.  Jupiter can be seen in the south/southeast sky when it gets dark.  Saturn will be seen in the southwest sky and continue to shine throughout most of the Summer.  The great constellation of Hercules will be practically above our heads as it approaches midnight.  With binoculars or a telescope be sure to check out M13, the great globular cluster of Hercules.

M13

The unfortunate part of Summer is that it gets dark very late.  It seems as though twilight rules throughout the night.  As we get deeper into July our dark sky will start coming back and there will be ample opportunity to observe the Summer constellations.

In July and August there will be several evenings of open houses at the Rothney Astrophysical Observatory dedicated to observing the Milky Way.  Keep your eyes posted for more information as the time approaches!