#the sunlight is dim there. the brightest noon is the same as dusk or dawn on earth

[tchaikovskym]

I'm glad catholics got to read the locked tomb as a catholic book, but I read it as a biologist, and everything was about biology to me. From genetics to ecology, about climate change and research grants, and most importantly, manipulation of live and used-to-be-live matter.

[astrogeoguy]

The Crown’s Jewels, the First Quarter Moon Meanders through Bright Planets, Jupiter bears Black and Red Spots, and Neptune Kisses a Star!

Above: On Wednesday, September 4 from 9:21 to 11:33 pm EDT, observers in the Americas can watch Io’s shadow transit Jupiter, accompanied by the Great Red Spot, as shown here for 10 pm EDT)

Hello, Late Summer Stargazers!

Here are your Astronomy Skylights for the week of September 1st, 2019 by Chris Vaughan. Feel free to pass this along to your friends and send me your comments, questions, and suggested topics. I repost these emails with photos at http://astrogeoguy.tumblr.com/ where all the old editions are archived. You can also follow me on Twitter as @astrogeoguy! Unless otherwise noted, all times are Eastern Time. Please click this MailChimp link to subscribe to these emails.

I can bring my Digital Starlab inflatable planetarium to your school or other daytime or evening event. Contact me, and we’ll tour the Universe together!

The Moon and Planets

If last week was the best week for skywatchers worldwide, this is the week for lunatics – the lovers of our natural satellite, Luna! Between now and next Sunday, the moon will March across the evening sky worldwide, waxing in phase and visiting two bright planets. Meanwhile, we have a minor meteor shower underway, and we can enjoy summer constellation sights in evening, autumn ones at midnight, and our winter treats during the pre-dawn hours. Here are your Skylights! 

The moon will begin the week as a delicate waxing crescent visible over the western horizon after sunset. Watch for Earthshine - sunlight that has reflected off the seas and white clouds of Earth and is illuminating the unlit portion of the moon’s near side. The bright, white star that you see below the moon (or above it, if you live south of the Equator) on Sunday and Monday evening is Spica, the brightest star in Virgo (the Maiden). Note how the moon moves with respect to that star from one night to the next. 

On Wednesday and Thursday, the now healthy crescent moon will pass through the modest stars of Libra (the Scales). The moon never wanders far from the Ecliptic, the imaginary line that traces the sun’s path through the zodiac constellations. So the moon is usually within those familiar constellations, allowing you to see where they are – even after the moon has moved away from them. 

Thursday will bring the First Quarter Moon phase - when the angle formed by the sun, Earth, and moon forms a right-angle, causing the moon to appear half-illuminated, on its eastern side. (East and west on the moon are opposite to sky directions on Earth.) First quarter moons always rise around noon time, allowing you to see them in the afternoon. Evenings around first quarter are the best ones for viewing the moon in binoculars and backyard telescopes. The topography along the terminator – the pole-to-pole line that divides the lit and dark halves – is being lit by low-angled sunlight which produces breathtaking vistas of bright mountain peaks and crater rims, and the deep black shadows they cast. Moon phases are shared by everyone around the world.

(Above: On Thursday, observers worldwide will see the First Quarter moon near very bright Jupiter, as shown here at 9:30 pm EDT. The following nights, the moon will hop east of Jupiter and then do the same for Saturn.) 

Thursday night will also begin the moon’s dance with the gas giant planets. Look for the moon in the southwestern sky, and positioned less than four finger widths to the right (or 4 degrees to the celestial northwest) of the bright planet Jupiter. The moon and Jupiter will both fit within the field of view of binoculars. If you watch the pair over several hours, starting at dusk, you will see the moon’s orbit carry it closer to the planet. Look for the bright reddish star Antares “the Rival of Mars” twinkling below the moon. That is the heart of Scorpius (the Scorpion). To the west of Antares, three little white stars in a vertical line and each separated by three finger widths from the next one, represent the critter’s claws. Remember that Jupiter will stay with the scorpion after the moon moves away – all autumn, in fact. 

On Friday night, the waxing gibbous (i.e., more than half-full) moon will hop to sit on the east side of Jupiter. Then, on Saturday night, the moon will land immediately above the Teapot-shaped stars of Sagittarius (the Archer), and a palm’s width the right (or celestial west) of Saturn. As with Jupiter, the moon will hop to the other side of Saturn on Sunday night – and the ringed planet will stay near the Teapot for the rest of this year.   

Mercury, Venus, and Mars are out of sight - hidden in the sun’s glare, for now. But the two fast inner planets will bring them into view in the evening sky next week. 

As the sky begins to darken this week, look for the giant planet Jupiter sitting less than a third of the way up the southwestern sky. Hour by hour, Jupiter will sink lower – then set in the west before midnight local time. Jupiter is spending the rest of this year between Ophiuchus (the Serpent-Bearer) and Scorpius (the Scorpion). Normally a planet becomes harder to see when it reaches the southwestern evening sky. But the earlier sunsets and the planet’s brilliance will keep it in view for some time to come. 

On a typical night, even a backyard telescope will show you Jupiter’s two main equatorial stripes and its four Galilean moons - Io, Europa, Callisto, and Ganymede looking like small white dots arranged in a rough line flanking the planet. If you see fewer than four dots, then some of them are in front of Jupiter, or hidden behind it. Good binoculars will show the moons, too! 

From time to time, the small, round, black shadows cast onto Jupiter’s surface by those four Galilean moons become visible in amateur telescopes as they cross (or transit) Jupiter’s disk. On Wednesday, September 4 from 9:21 to 11:33 pm EDT, observers in the Americas can watch Io’s shadow transit Jupiter, accompanied by the Great Red Spot! 

Due to Jupiter’s rapid 10-hour rotation period, the Great Red Spot (or GRS) is only observable from Earth every 2nd or 3rd night, and only during a predictable three-hour window. The GRS will be easiest to see using a medium-sized, or larger, aperture telescope on an evening of good seeing (steady air). If you’d like to see the Great Red Spot in your telescope, it will be crossing the planet on Monday evening from dusk to 11 pm EDT, on Wednesday from 9:20 to 11:30 pm EDT (accompanied by the Great Red Spot), and on Saturday from dusk until 10 pm EDT. 

Yellow-tinted Saturn is prominent in the southern evening sky, too - but it is less bright than Jupiter. The ringed planet will be visible from dusk until about 2 am local time. Saturn’s position in the sky is just to the upper left (or celestial east) of the stars that form the teapot-shaped constellation of Sagittarius (the Archer). To find Saturn, look about 3 fist diameters to the left (east) of Jupiter. The Milky Way is between them. 

Dust off your telescope! Once the sky is dark, even a small telescope will show Saturn's rings and several of its brighter moons, especially Titan! Because Saturn’s axis of rotation is tipped about 27° from vertical (a bit more than Earth’s axis), we can see the top surface of its rings, and its moons can arrange themselves above, below, or to either side of the planet. During this week, Titan will migrate counter-clockwise around Saturn, moving from the upper left of Saturn tonight (Sunday) to below the planet next Sunday. (Remember that your telescope will flip the view around.) 

Tiny, blue Neptune will rise at dusk this week, and then it will climb the eastern sky until it reaches its highest point, due south, at about 1:30 am local time. The planet is among the stars of Aquarius (the Water-Bearer). Recently, Neptune has been sitting just to the left (celestial east) of a medium-bright star named Phi (φ) Aquarii. Neptune is actually moving slowly toward that star and will “kiss” it on Thursday and Friday nights this week, an event that will help you locate dim Neptune.

Astronomers call such an event a conjunction. Being so close together, both the star and Neptune will appear together in the field of view of a telescope. But blue Neptune’s light has been travelling for 4 hours to reach your eye, while the warmly-tinted light of Phi Aquarii has been journeying for 202 years! After this weekend, the distance between the two objects will increase due to Neptune’s eastward orbital motion.

(Above: The path of blue Neptune past the medium-bright stat Phi Aquarii will produce a close conjunction on September 5 and 6. Each yellow dot represents 6 hours of Neptune’s orbital motion this week. They will make an interesting sight in backyard telescopes.)  

Blue-green Uranus will be rising in the east just before 10 pm local time this week; and it will remain visible all night long. Uranus is sitting below (celestial south of) the stars of Aries (the Ram) and is just a palm’s width above the head of Cetus (the Whale). At magnitude 5.8, Uranus is actually bright enough to see in binoculars and small telescopes, under dark skies – and it really does look blue! You can use the three modest stars that form the top of the head of the whale (or sea-monster in some tales) to locate Uranus for months to come – that’s because that distant planet moves so slowly in its orbit. To help you find it, I posted a detailed star chart here.

(Above: The Ice Giant planets are visible in late evening, as shown here at 10:30 pm local time.)  

Aurigids Meteor Shower

A minor meteor shower named the Aurigids is underway. It peaks today (Sunday) and ends next weekend. Look for several of these meteors per hour. They’ll be moving away from the northeastern horizon, where the constellation that gives them their name, Auriga (the Charioteer), rises in late evening. 

The Northern Crown Rests in the West

Corona Borealis (the Northern Crown) can be spotted halfway up the western evening sky in early September. The constellation actually sits about midway along the imaginary line that joins the two bright stars Vega and Arcturus. The earlier autumn sunsets extend our opportunity to explore Corona Borealis. This incomplete circlet of medium-bright stars is roughly 7 degrees across (a generous palm’s width). It is both a constellation and an asterism (an informal star pattern). Corona Borealis’ brightest star Alphecca is a white, A-class star located 75 light-years from the sun. Alphecca’s placement in the constellation is reminiscent of a diamond in a ring. The star’s name derives from the Arabic expression for “broken”, referring to the incomplete ring.

(Above: The distinctive constellation of Corona Borealis, the Northern Crown, sits in the western evening sky - midway between the two bright stars Vega (at top centre) and Arcturus. The sky is shown for 10 pmlocal time this week.)

While the Northern Crown is poor in deep sky objects, it contains several interesting jewels -  double and variable stars. Alphecca itself is an eclipsing binary system that varies in brightness by a tiny amount every 17.36 days, similar to the behavior of the star Algol in Perseus (the Hero). Eruptive variable stars are named for R Coronae Borealis, which is located about three finger widths above (or 3.5 degrees to the celestial northeast of) Alphecca. R Corona Borealis is a hydrogen-deficient and carbon-rich supergiant star. From time to time, it’s usual visual magnitude of 5.8 drops to as little as magnitude 14, possibly due to the formation of opaque carbon dust that blocks visible light, but passes infrared wavelengths. Another star named S Coronae Borealis exhibits the same range of variability, but with a 360-day period. The Blaze Star (T Coronae Borealis) is a cataclysmic variable star, also called a recurrent nova-type. Normally shining between visual magnitude 10.2 and 9.9, on rare occasions it has brightened to magnitude 2 in a period of hours, caused by a nuclear chain reaction and the subsequent explosion.

(Above: The crown’s jewels include the variable stars R, S, and T Coronae Borealis)   

August-September Stargazing Suggestions - Lyra

If you missed last week’s tour of the constellation of Lyra (the Harp), I posted it here. Over the next weeks, we’ll look at some other constellations, too. 

Public Astro-Themed Events

Taking advantage of the moon and other bright objects in the sky this week, the RASC Toronto Centre astronomers will hold their free monthly public City Sky Star Party in Bayview Village Park (steps from the Bayview subway station), starting around 8 pm on the first clear weeknight this week (Tues to Thu only). You don’t need to be an RASC member, or own any equipment, to join them – looks are free! Check here for details, and check the banner on their website home page or Facebook page for the GO or NO-GO decision around 5 pm each day. 

Every Monday evening, York University’s Allan I. Carswell Observatory runs an online star party - broadcasting views from four telescopes/cameras, answering viewer questions, and taking requests! Details are here. On Wednesday nights they offer free public viewing through their rooftop telescopes. If it’s cloudy, the astronomers give tours and presentations. Details are here. 

If the skies are clear on Thursday evening, September 5, local astronomers will set up their telescopes in Old Thornhill Village. This free event starts at 8 pm and everyone is welcome to come out for a look at the Moon, Jupiter and Saturn, and a variety of deep-sky treasures. The viewing location is Thornhill's very own “dark-sky oasis,” the Pomona Meadow - situated north of the cemetery on Charles Lane, and east of the Ukrainian Catholic Church of St. Volodymyr. Park for free at the church and just follow the paved path. The rain or cloud date is Thursday, October 3 at 7:00 pm. Dress warmly, and we’ll see you there! 

Eastern GTA sky watchers are invited to join the RASC Toronto Centre and Durham Skies for solar observing and stargazing at the edge of Lake Ontario in Millennium Square in Pickering on Friday evening, September 6, from 6 pm to 11 pm. Details are here. Before heading out, check the RASCTC home page for a Go/No-Go call in case it's too cloudy to observe. The rain date is Saturday. That same evening, RASC and Durham Skies will be donating a telescope to the Pickering Public Library in a public ceremony. In case of rain or bad weather, the ceremony will be moved to the Pickering Library Auditorium (2nd floor) at 1 The Esplanade. 

If it’s sunny on Saturday morning, September 7 from 10 am to noon, astronomers from the RASC Toronto Centre will be setting up outside the main doors of the Ontario Science Centre for Solar Observing. Come and see the Sun in detail through special equipment designed to view it safely. This is a free event (details here), but parking and admission fees inside the Science Centre will still apply. Check the RASC Toronto Centre website or their Facebook page for the Go or No-Go notification. 

Please note: Due to some filming permits at DDO, some of our events in September have been cancelled. Here’s the updated information… 

The next RASC-hosted Night at the David Dunlap Observatory will be on Saturday, September 21. There will be sky tours in the Skylab planetarium room, space crafts, a tour of the giant 74” telescope, and viewing through the 74” and lawn telescopes (weather permitting). The doors will open at 8:30 pm for a 9 pm start. Attendance is by tickets only, available here. If you are a RASC Toronto Centre member and wish to help us at DDO in the future, please fill out the volunteer form here. And to join RASC Toronto Centre, visit this page. 

This Fall and Winter, spend a Sunday afternoon in the other dome at the David Dunlap Observatory! On Sunday afternoon, October 20, from noon to 4 pm, join me in my Starlab Digital Planetarium for an interactive journey through the Universe. We’ll tour the night sky and see close-up views of galaxies, nebulas, and star clusters, view our Solar System's planets and alien exo-planets, land on the moon, Mars - and the Sun, travel home to Earth from the edge of the Universe, hear indigenous starlore, and watch immersive fulldome movies! Ask me your burning questions, and see the answers in a planetarium setting - or sit back and soak it all in. Sessions run continuously between noon and 4 pm. Ticket-holders may arrive any time during the program. The program is suitable for ages 3 and older, and the Starlab planetarium is wheelchair accessible. For tickets, please use this link.

Keep looking up, and enjoy the sky when you do. I love questions and requests - so, send me some! 

[astrogeoguy]

Venus and Jupiter Dance at Dusk, Lyrid Meteors Linger a Bit, and the Sprouting Grass Moon Grows Full!

(Above: This image of January 31, 2018 full perigee moon was captured by Michael Watson of Toronto. The bright rays emanating from major craters are especially visible during full moon periods.)

Astronomy Skylights for this week (from April 15th, 2018) by Chris Vaughan. (Feel free to pass this along to friends and send me your comments, questions, and suggested topics.) I post these with photos at http://astrogeoguy.tumblr.com/ where the old editions are archived. You can also follow me on Twitter as @astrogeoguy! Unless otherwise noted, all times are Eastern Time. Please click this MailChimp link to subscribe to these emails. If you are a teacher or group leader interested joining me on a guided field trip to York University’s Allan I. Carswell Observatory, or another in your area, visit www.astrogeo.ca.

If you’d like me to bring my Digital Starlab inflatable planetarium to your school or other daytime or evening event, visit DiscoveryPlantarium.com and request me. We’ll tour the Universe together!

Public Events

Taking advantage of the moon and other bright objects in the sky this week, the RASC Toronto Centre astronomers will hold their free monthly public City Sky Star Party in Bayview Village Park (steps from the Bayview subway station), around 8 pm on the first clear weeknight this week (except Wed and Fri). You don’t need to be an RASC member, or own any equipment, to join them. Check here for details, and check the banner on their website home page or Facebook page for the GO or NO-GO decision around 5 pm each day. 

On Monday evenings, York University’s Allan I. Carswell Observatory runs an online star party - broadcasting views from four telescopes/cameras, answering viewer questions, and taking requests! Details are here. On Wednesday evenings after dark, they offer free public viewing through their telescopes. If it’s cloudy, the astronomers give tours and presentations. Details are here. 

At 7:30 pm on Wednesday, April 25, the RASC Toronto Centre will hold their free monthly Recreational Astronomy Night Meeting at the Ontario Science Centre. The public are welcome. Talks include the Sky This Month, amateur telescope-making, and more. Check here for details. Parking is free. 

If it’s sunny on Saturday morning, April 28 from 10 am to noon, astronomers from the RASC Toronto Centre will be setting up outside the main doors of the Ontario Science Centre for Solar Observing. Come and see the Sun in detail through special equipment designed to view it safely. This is a free event (details here), but parking and admission fees inside the Science Centre will still apply. Check the RASC Toronto Centre website or their Facebook page for the Go or No-Go notification. 

On Tuesday, April 24, starting at 8:30 pm, the RASC Mississauga will host a free public star party at the Riverwood Conservancy. Details are here. 

On Friday, April 27, starting at 7 pm, the U of T AstroTour will present their planetarium show entitled The Life and Death of Stars. Tickets and details are here. 

On Saturday, April 28, from 9 am to 4 pm, Discover the Universe will present a free workshop geared toward teachers of Grade 9 astronomy. It will take place at U of T’s Cody Hall on St. George Street. Registration and details are here. 

(Above: The radiant of the annual Lyrids Meteor shower is located between Lyra and Hercules. The shower will taper off through mid-week.)

Lyrids Meteor Shower

The annual Lyrids meteor shower, derived from particles dropped by comet C/1861 G1 (Thatcher) peaked before dawn this morning (Sunday), but you can watch for fewer of them until mid-week. This shower can produce up to 18 meteors per hour, with occasional fireballs. True Lyrids will appear to be travelling away from a point in space (the shower’s radiant) near the constellation Lyra (the Harp). 

The Moon and Planets

Late this afternoon (Sunday) the moon reaches its First Quarter Moon phase, when it will appear half-illuminated among the dim stars of Cancer (the Crab). The evenings surrounding first quarter are the best ones for looking at the moon under magnification. The steeply slanted sunlight creates breathtaking vistas along the terminator boundary line that divides the dark and light sides of the moon. To see the sights, sweep with binoculars or a telescope from pole to pole. At first quarter, the moon rises in early afternoon – so you can also spot it in the daytime eastern sky. 

(Above: Shown here at 8:30 pm local time on Tuesday evening, the moon will sit close to the bright star Regulus in Leo. Parts of the world will see the moon occult the star.)

After darkness falls on Tuesday evening, look for bright white Regulus, Leo’s brightest star, sitting a few finger widths to the right of the waxing gibbous moon. Several hours earlier, near 19:00 UT, observers in Central Russia and the northeastern tip of Kazakhstan can see the moon pass in front of (or occult) Regulus. 

Next Sunday evening brings us the full moon. (Everyone on Earth sees the same phase on the moon, although the moon may not be above their horizon at the moment that a phase happens.) The April full moon is called the Pink Moon, Sprouting Grass Moon, Egg Moon, or Fish Moon, after Mother Nature’s stirrings this time of year. And the April full moon always shines in or near the stars of Virgo (the Maiden). Because full moons sit more or less exactly opposite the sun in the sky, they always rise in the east just as the sun sets, and set in the west at sunrise. 

When we face a rising full moon, the sun is shining on it from behind us – the same way the projector illuminates the screen in a cinema. The entire Earth-facing hemisphere of the moon is being illuminated by sunlight hitting it at a steep angle – like summertime noonday sun on Earth. As a result, no shadows appear on a full moon, and all of the brightness differences we see are generated by the reflectivity, or albedo, of the various types of rocks on the lunar surface.

(Above: On Tuesday evening, April 24, Venus, which climbs higher every evening in its orbit (white line), will reach a position a few degrees to the lower left of the bright Pleiades Cluster, as shown here at 9:25 pm local time.)  

Venus is now firmly ensconced in the western early evening sky, catching the eye until it sets, two hours after the sun - at about 10:30 pm local time. The planet is slowly climbing the western sky as its orbit increases its angle from the sun. As a result, on Tuesday evening, our sister planet will also pass within a few finger widths of the bright star cluster known as the Pleiades, or the Seven Sisters, in Taurus (the Bull). Try to spot the cluster with unaided eyes or, even better, with binoculars, once the sky has darkened. 

(Above: This week, Venus and Jupiter will occupy similar positions above the western and eastern horizons respectively, as shown here at 9:25 pm local time. The Ecliptic (green line) roughly defines the plane of our solar system.)

Shortly after 10 pm local time this week, very bright Jupiter will be just above the eastern horizon while Venus is a similar height above the western horizon. Jupiter dominates the overnight sky now. Jupiter reaches its highest elevation (about three fist diameters) above the southern horizon around 2 am local time, and then descends into the southwestern sky at sunrise. 

The Great Red Spot takes about three hours to cross Jupiter’s disk. But the planet’s 10-hour rotation period (i.e., its day) means that the spot is only observable from Earth every 2-3 nights.  If you’d like to see the GRS, use a medium-sized telescope (or larger). You’ll have your best luck on evenings with steady air – when the stars are not twinkling too much. The best times to try this week are: Tuesday, April 24 at 12:09 am and Saturday, April 28 at 11:16 pm. Try to look within an hour before or after the times I’ve given. 

The ringed planet Saturn will be rising in the east just after 1 am local time this week. You should be able to see its yellow-tinted point of light until about 6 am, when it will sit about 2.5 fist widths above the southern horizon. Reddish Mars will rise about 50 minutes after Saturn, which places it a fist’s width to the lower left of Saturn. Mars is continuing to brighten slowly as the Earth’s faster orbit brings us closer to the red planet. We will eventually pass it on the “inside track” in late July.

(Above: Three bright planets continue to shine in the pre-dawn sky this week, as shown here at 5:30 am local time. Jupiter rises in late evening, but remains in view until dawn.)  

This week Mercury continues to creep across the eastern pre-dawn horizon in an appearance that isn’t very good for observers in mid-northern latitudes. That said, next Sunday it will reach its widest separation west of the sun and peak visibility. Your best time to hunt for it will be between about 5:45 and 6 am local time that morning. If you live south of the equator, however, Mercury will be very easy to see for the next couple of weeks. I’ll post sky charts for the observable planets here.

(Above: On Sunday, April 29, Mercury will reach its maximum angle west of the sun, and peak visibility, during a very poor apparition for northern hemisphere observers. It is shown here at 5:15 am local time.)

Keep looking up to enjoy the sky! I love getting questions so, if you have any, send me a note.

[astrogeoguy]

A Pretty Evening Moon, Pre-Perseids Meteors, and Aquila the Eagle Soars in the East!

(Above: The Wild Duck Cluster, also known as Messier 11, imaged by Michael Watson of Toronto in July, 2015. More of his images are here.)

Hello, Summer Stargazers!

Here are your Astronomy Skylights for the week of August 4th, 2019 by Chris Vaughan. Feel free to pass this along to your friends and send me your comments, questions, and suggested topics. I repost these emails with photos at http://astrogeoguy.tumblr.com/ where all the old editions are archived. You can also follow me on Twitter as @astrogeoguy! Unless otherwise noted, all times are Eastern Time. Please click this MailChimp link to subscribe to these emails.

I can bring my Digital Starlab inflatable planetarium to your school or other daytime or evening event. Contact me, and we’ll tour the Universe together!

The Perseids Meteor Shower is Building

The prolific Perseids Meteor Shower is already building, so keep an eye out for a few of them this week. The almost full moon will spoil the show on the peak nights of August 12/13, so take advantage of the darker skies this week. 

To increase your chances of seeing any meteors, find a dark location with lots of sky, preferably away from light polluted skies, and just look up with your unaided eyes. Binoculars and telescopes are not useful for meteors because their fields of view are too narrow to fit the streaks of meteor light. Don’t watch the radiant. Any meteors near there will have very short trails because they are travelling towards you. Try not to look at your phone’s bright screen – it’ll ruin your night vision. And keep your eyes heavenward, even while you are chatting with companions. I’ll write more about the Perseids next week. For now, happy hunting! 

The Moon and Planets

This week, the moon will grace the evening sky worldwide as it waxes in phase and swings away from the sun. In the process, it will pay Jupiter a visit, and then end the week next to Saturn. It’s also the best week of the lunar month to view the moon because the sunlight reaching the moon is coming in shallowly from the east – casting deep shadows to the west of even the slightest topographic elevation. Gorgeous vistas in binoculars and telescopes run pole-to-pole along the moon’s terminator – the line that separates the lit and dark hemispheres. As a bonus, the slowly rising sun shifts the terminator west every night. Here are your Skylights for this week! 

After sunset tonight (Sunday), look for a very pretty, delicate crescent moon shining in the western sky for a short time after dusk. On Monday, the moon will be higher and farther from the sun. The bright white star Spica in Virgo (the Maiden) will be positioned a palm’s width to the moon’s lower left (celestial south). 

On Wednesday the moon will complete the first quarter of its orbit around Earth, when the relative positions of the Earth, sun, and moon cause us to see it half-illuminated - on its eastern side. At first quarter, the moon always rises around noon and sets around midnight, so it is also visible in the afternoon daytime sky. 

On Thursday evening, the waxing moon will pass through dim Libra (the Scales) and land above the line of three modest stars that form Scorpius’ pincers. On Friday, the waxing gibbous moon will land 1.5 finger widths to the upper left (northeast) of the bright planet Jupiter. If you glance at the moon and Jupiter over several hours, starting at dusk, you will see the moon’s orbit carry it farther from the planet. 

In the southeastern sky after dusk on Sunday evening, the bright, waxing gibbous moon will be positioned four finger widths to the right of the bright, yellowish planet Saturn. The pair will cross the sky together for most of the night and will easily appear together within the field of binoculars. Once again, if you watch them over several hours, starting at dusk, you will see the moon’s orbit carry it closer to the planet and the rotation of the sky lift Saturn higher than the moon. Observers in eastern Indonesia, most of Australia, northern New Zealand, Melanesia, and Polynesia (except Hawaii) will see the moon occult Saturn on August 12. 

This week, Jupiter will continue to outshine the stars. After dusk, look for Jupiter in the southwestern sky. It will set in the west at about 1:30 am local time. On a typical night, even a backyard telescope will show you Jupiter’s two main equatorial stripes and its four Galilean moons, named Io, Europa, Callisto, and Ganymede. The moons always form a rough line flanking the planet. If you see fewer than four, then some are in front of Jupiter, or hidden behind it. 

Due to Jupiter’s rapid 10-hour rotation period, the Great Red Spot (or GRS) is only observable from Earth every 2nd or 3rd night, and only during a predictable three-hour window. The GRS will be easiest to see using a medium-sized, or larger, aperture telescope on an evening of good seeing (steady air). If you’d like to see the Great Red Spot in your telescope, it will be crossing the planet tonight (Sunday evening) from dusk to 11:30 pm EDT, on Tuesday night from 10:30 pm to 12:30 am EDT, after dusk on Friday, and from 10 pm to midnight EDT next Sunday. I posted a calendar of Jupiter’s doings here.

(Above: This summer, bright Jupiter and Saturn are flanking the Milky way in the evening sky. Dimmer Saturn is positioned about three fist diameters to the east of Jupiter. On Sunday, August 11, the waxing gibbous moon will land near Saturn, as shown here at 10 pm local time.) 

Yellow-tinted Saturn will remain visible from dusk until about 4 am local time. The ringed planet’s position in the sky is just to the upper left (celestial east) of the stars that form the teapot-shaped constellation of Sagittarius (the Archer). Saturn is quite a bit dimmer than Jupiter. To find it, look about 3 fist diameters to the lower left (east) of Jupiter. Dust off your telescope! Once the sky is dark, even a small telescope will show Saturn's rings and several of its brighter moons, especially Titan! Because Saturn’s axis of rotation is tipped about 27° from vertical (a bit more than Earth’s axis), we can see the top surface of its rings, and its moons can appear above, below, or to either side of the planet. During this week, Titan will migrate counter-clockwise around Saturn, moving from the lower left of Saturn tonight (Sunday) to the right of the planet next Sunday. (Remember that your telescope will flip the view around.)

(Above: The ice giant planets Uranus and Neptune are available overnight, as shown here at midnight local time.)

Tiny blue Neptune is in the southeastern sky in late evening, among the stars of Aquarius (the Water-Bearer). The planet will be rising shortly before 10 pm local time this week. You’ll find the magnitude 7.8 Neptune sitting a thumb’s width to the left (east) of a medium-bright star named Phi (φ) Aquarii. The planet is actually moving slowly toward that star! 

Blue-green Uranus will be rising just before midnight local time this week. It is sitting below the stars of Aries (the Ram) and is just a palm’s width above the head of Cetus (the Whale). At magnitude 5.8, Uranus is bright enough to see in binoculars under dark skies. 

This week, Mercury is in the northeastern pre-dawn sky - below the stars of Gemini (the Twins). It will continue to climb away from the sun this week. Your best opportunity to see it will land between 5 and 5:30 am local time. 

Venus and Mars are lost in the sun’s glare for the next while.

(Above: Mercury will make a nice appearance in the eastern pre-dawn sky this week, as shown here at 5:30 am local time.)  

Aquila the Eagle

Look halfway up the southeastern sky in early August evenings, and you’ll easily spot the bright, white star Altair, sitting at the bottom corner of the Summer Triangle asterism. Altair is the brightest star in the venerable constellation of Aquila (the Eagle) and marks the great bird’s head. The eagle’s body and tail extend downwards to the right, more or less following the Milky Way. The wings extend upwards and downwards.  

(Above: Aquila the Eagle occupies the southeastern evening sky every summer in early August.)

Aquila so clearly resembles a bird that many cultures have seen the same pattern in its stars, including the Babylonians. In Greek mythology, it was the eagle that held Zeus’ thunderbolts. The Romans called it Vultur volans “the flying vulture”. The Hindus associated the stars with the half eagle-half human god Garuda. 

Classic Chinese poetry told a well-known story about the Weaver Girl and the Cowherd, one of the four great folktales. In this tale, Zhinü 織女 the weaver girl was in love with Niulang 牛郎 the cowherd. To prevent their forbidden love, they were banished to the heavens, and Zhinu, represented by the nearby bright star Vega, and Niulan, represented by Altair, were separated by the Silver River, or Milky Way. Two small stars visible on either side of Altair represent their children. In the story, once a year on the 7th day of the 7th month, a flock of magpies would form a bridge, reuniting the lovers for one day only. 

Altair is Arabic for “flying eagle”. The star itself is a yellow-white star about ten times larger than our Sun, and only a mere 17 light-years away, making it the twelfth brightest star in the night sky. At 10 hours, its rotation rate is one of the fastest known, spinning so rapidly that the star has an oblate shape (wider at the equator than it is tall). In the sky, Altair is symmetrically flanked by two small stars named Alshain and Tarazed. Because the three stars resemble a weighing balance, their names are derived from the Arabic phrase for one, "shahin-i tarazu". The trio span about three finger widths, or 5° of separation. Tarazed, on the right, is an interesting star. It is a cool, orange giant star located 460 light-years away and shining at almost 3,000 times the luminosity of our Sun; and it emits an abundance of X-rays! 

The rest of Aquila’s stars are dimmer, but nonetheless visible to unaided eyes. Almost a fist’s diameter to the lower right of Altair is the star Delta Aquilae, representing the body. The wings are each about a fist diameter in length. The upper wing has the star Okab at the tip. The lower wing is formed by two widely spaced stars named Almizan I and Almizan II. (Some apps use the designations Eta and Theta Aquilae.) The eagle’s tail is marked by a pair of small stars a finger’s width apart. The brighter tail star is named Al Thalimain “the two ostriches”. The Pioneer 11 spacecraft launched in 1973 is coasting towards this star, with an arrival time of about 4 million years! 

Sweep your binoculars though the area around Aquila to see an abundance of stars from the nearby galactic plane. About a palm’s width below the eagle’s tail, you’ll easily spot another avian object – The Wild Duck Cluster or Messier 11 – a famous bright open cluster. Good “hunting”! 

A Summer Triangle Tour

If you missed last week’s tour of the three bright and beautiful blue-white stars of the Summer Triangle asterism, which shines high in the eastern sky in late July and early August, it’s here. 

Public Astro-Themed Events

Taking advantage of the moon and other bright objects in the sky this week, the RASC Toronto Centre astronomers will hold their free monthly public City Sky Star Party in Bayview Village Park (steps from the Bayview subway station), starting around 8 pm on the first clear weeknight this week (Mon to Thu only). You don’t need to be an RASC member, or own any equipment, to join them – looks are free! Check here for details, and check the banner on their website home page or Facebook page for the GO or NO-GO decision around 5 pm each day. 

Every Monday evening, York University’s Allan I. Carswell Observatory runs an online star party - broadcasting views from four telescopes/cameras, answering viewer questions, and taking requests! Details are here. On Wednesday nights they offer free public viewing through their rooftop telescopes. If it’s cloudy, the astronomers give tours and presentations. Details are here. 

On Tuesday, August 6, starting at 7 pm, U of T’s AstroTour will present their planetarium show The Life and Death of Stars. Tickets and details are here. 

Weather permitting, on Tuesday, August 6 from 8:30 to 10 pm, astronomers from RASC – Mississauga will hold a free public star party at the Riverwood Conservancy, 4300 Riverwood Park Lane, Mississauga. Details are here. 

On Wednesday, August 7 from 12:30 to 2 pm, the Ontario Science Centre will present a Space Start-up Showcase, featuring Canadian astronaut Dave Williams and other experts. Free with admission to the OSC. Details are here. 

On Thursday, August 8, starting at 7 pm, U of T’s AstroTour will present their planetarium show Our Musical Universe. Tickets and details are here. 

On Thursday, August 8, starting at 7 pm, U of T’s Physics Department will host a free presentation by Nobel Laureate Dr. Arthur McDonald entitled From the tiniest particles to the farthest reaches of the Universe. Registration and details are here. 

On Friday evening, August 9 from 8 to 11 pm at the Binbrock Conservation Area, the Hamilton astronomers will present a free public Perseid Meteor Shower Watch party. Details are here. 

If it’s sunny on Saturday morning, August 10 from 10 am to noon, astronomers from the RASC Toronto Centre will be setting up outside the main doors of the Ontario Science Centre for Solar Observing. Come and see the Sun in detail through special equipment designed to view it safely. This is a free event (details here), but parking and admission fees inside the Science Centre will still apply. Check the RASC Toronto Centre website or their Facebook page for the Go or No-Go notification. 

The next RASC Family Night at the David Dunlap Observatory will be on Saturday, August 10. There will be sky tours in the Skylab planetarium room, space crafts, a tour of the giant 74” telescope, and viewing through lawn telescopes (weather permitting). The doors will open at 8:30 pm for a 9 pm start. Attendance is by tickets only, available here. If you are a RASC Toronto Centre member and wish to help us at DDO in the future, please fill out the volunteer form here. And to join RASC Toronto Centre, visit this page.

Keep looking up, and enjoy the sky when you do. I love questions and requests - so, send me some!