Astronomy: The Week Ahead – Sun 23 Aug to Sat 29 Aug 2015

SA23 title

Sunday, August 23th:


The bright star near the moon is Antares in the constellation Scorpius the Scorpion. You’ve got about another month or two to see this uniquely summer star for us in the Northern Hemisphere, during the evening hours. Antares is the brightest star near the moon tonight, while the other nearby bright beauty is the planet Saturn.

If you’re in the Northern Hemisphere, Antares and Saturn are visible in the southern to southwest sky as night begins. If you’re in the Southern Hemisphere, they’re more overhead for you.

The moon has now passed the first quarter phase and now exhibits a slight curvature to its terminator line – the line between dark and light on the moon. This moon phase is called waxing gibbous. The waxing gibbous moon, Antares and Saturn will drift westward throughout the night, to set at late evening or round midnight at mid-northern latitudes.

Like all stars, Antares sets some 4 minutes earlier with each passing night, or 2 hours earlier with each passing month. By October, this star will be tough to spot in the southwestern twilight after sunset.

In ancient Chinese thought, the summer season was associated with the direction south, with the element fire, and with the color red. No wonder, then, that this reddish star in the south each summer – beautiful Antares – was considered the Fire Star of the ancient Chinese.

Antares appears as a bright reddish star that rides relatively low in the south throughout our northern summer. We know it as a great ball of gases, a thermonuclear cauldron radiating unimaginable amounts of energy into the blackness and vastness of space.

Yet to us – as to the ancient Chinese – Antares appears so near the southern horizon that we must view it through a great thickness of air. The air through which we view Antares causes this star to twinkle rapidly! On any summer evening, if you see a bright red star low in the south that’s twinkling fiercely … it’s probably Antares.

The basics: The bright star near the moon on August 23, 2015 is Antares, brightest star in the constellation Scorpius. This star can be seen near the moon tonight from around the world.

Monday, August 24th:


The moon can be found above the famous Stinger stars of Scorpius the Scorpion. These stars are called Shaula and Lesath.

As seen from mid-northern latitudes in North America, the Stinger stars loom close to the southern horizon at early evening, a good fist-width below tonight’s waxing gibbous moon. Depending on where you live worldwide, the moon’s position relative to the Scorpion’s Stinger stars varies somewhat.

If you live in Europe or Africa, the moon appears offset closer to Antares, Scorpius’ brightest star.

Asian viewers see the moon even more offset toward Antares.

Those residing in the Southern Hemisphere will see the moon, Antares and the Stinger stars high overhead, not close to the horizon.

When the moon drops out of the evening sky – toward the end of the first week in September – you can use these same Stinger stars to envision the constellation Scorpius, with its graceful curved tail. Plus, you’ll be able to plus star-hop to two beautiful deep-sky treasures: the star clusters M6 and M7.

Your binoculars are perfect for finding M6 and M7, assuming you have a dark sky. They fit within a single binocular field of view.

Your binoculars are perfect for finding M6 and M7, assuming you have a dark sky. They fit within a single binocular field of view.

In the lore of the skies, the Scorpion’s stinger put Orion the Hunter to death.

According to another version of the tale, Orion was accidentally killed by his lover, Artemis.Ophiuchus, the constellation to the immediate north of Scorpius, is said to depict the doctor Ascelpius, who tried to bring Orion back to life. Yet Hades, the god of the Underworld, appealed to Zeus to forbid Ascelpius from raising the dead, for the practice goes against the natural order of things.

The constellation Scorpius is opposite in our sky to the constellation Orion, which is up before dawn now. See the three medium-bright stars at the center of the constellation Orion? Those three stars are Orion’s Belt, and they always point to Sirius, the Dog Star and sky’s brightest star.

The constellation Scorpius is opposite in our sky to the constellation Orion, which is up before dawn now. See the three medium-bright stars at the center of the constellation Orion? Those three stars are Orion’s Belt, and they always point to Sirius, the Dog Star and sky’s brightest star.

The basics: On August 24, 2015, the moon is above the famous Stinger stars – Shaula and Lesath – of the constellation Scorpius the Scorpion.

Tuesday, August 25:


Venus – the second planet outward from the sun and brightest planet visible in Earth’s sky – swung in between Earth and the sun. At that time, Venus transitioned out of Earth’s evening sky and into our morning sky. Unless you have special equipment, you probably haven’t seen Venus for a few weeks.

After having been lost in the sun’s glare for several weeks, Venus returns to visibility in the morning sky this week (beginning around August 26, 2015). On that approximate date – or on a morning around that date – you might see Venus climbing up above the eastern horizon an hour or so before sunrise – if you have an unobstructed eastern horizon and clear sky.

If you miss Venus this week, look for it to appear in the morning sky someday soon.

What will Venus look like before dawn? Here it is shortly before it slipping into the sunset in early August. This is Venus (brightest), Jupiter and Mercury low in the twilight on August 3, 2015. Photo by Peter Lowenstein in Mutare, Zimbabwe.

What will Venus look like before dawn? Here it is shortly before it slipping into the sunset in early August. This is Venus (brightest), Jupiter and Mercury low in the twilight on August 3, 2015. Photo by Peter Lowenstein in Mutare, Zimbabwe.

Just don’t mistake Sirius – the brightest star of the nighttime sky – for the planet Venus. Sirius sparkles in the southeast, while Venus shines with a steadier light almost due east. Although Venus is actually brighter than Sirius, Venus might be the harder of the two to spot in the morning sky right now, because Venus sits closer to the glare of sunrise. Click here for more information about Sirius in the morning sky.

The illustration below enables you to get some perspective of Venus’ and Earth’s orbits around the sun. We’re looking down upon the plane of the solar system from the north side. From this vantage point, the planets revolve counter-clockwise around the sun.

Not to scale. The radius of Venus’ orbit is about 0.72 of Earth’s distance from the sun (0.72 of an astronomical unit).

Not to scale. The radius of Venus’ orbit is about 0.72 of Earth’s distance from the sun (0.72 of an astronomical unit).

The passage of Venus between the Earth and sun took place on August 15, 2015. Astronomers call this an inferior conjunction of Venus. At such times, Venus in its smaller and swifter orbit passes in between the Earth and sun. We should mention that only planets that orbit the sun inside of Earth’s orbit (Mercury and Venus) have inferior conjunctions.

After inferior conjunction, Venus always moves westward of the rising sun in our sky until reaching itsgreatest western elongation (46o) – farthest angular distance from the rising sun – some 72 days later.

Venus will next reach greatest western (morning) elongation on October 26, 2015. It’ll look like a miniature half-lit quarter moon through the telescope. That’s because Venus’ disk always appears about 50% illuminated by sunshine at any greatest elongation.

Midway between inferior conjunction and greatest western elongation, Venus will shine at its brightest as the morning “star” on September 21, 2015. That’s in spite of the fact that Venus’ disk is only about one-quarter illuminated by sunshine whenever it’s midway between an inferior conjunction and a greatest elongation.

This brilliant world will remain in the morning sky until reaching superior conjunction on June 6, 2016, to transition back into the evening sky.

The basics: Starting around August 26, 2015, start watching for dazzling Venus to illuminate the sky before sunrise.

Wednesday August 26th:


Every year, during the last week of August, a first hint of the changing of the seasons can be seen in the predawn sky: Orion the Hunter and Sirius the Dog Star. The very noticeable constellation Orion the Hunter rises before dawn at this time of year, recognizable for the short straight line of three stars that make up Orion’s Belt. And the sky’s brightest star Sirius – sometimes called the Dog Star because it’s part of the constellation Canis Major the Greater Dog – follows Orion into the sky at or close to dawn. Have you noticed a very bright, madly twinkling star in the predawn sky? Many do, at this time of year. That star is Sirius. It’s so bright that, when it’s low in the sky, it shines with glints of red and flashes of blue – very noticeable!

Orion and the nearby star Sirius will become visible in the evening by northern winter (or southern summer). But presently the Hunter and the Dog Star lord over the southeastern sky at dawn’s first light.

The brightest star in this photo is Sirius, the sky’s brightest star. Notice Orion’s Belt stars in the upper left of this photo and how the Belt stars always point to Sirius. Photo courtesy of Leif Boracay.

The brightest star in this photo is Sirius, the sky’s brightest star. Notice Orion’s Belt stars in the upper left of this photo and how the Belt stars always point to Sirius. Photo courtesy of Leif Boracay.

Orion was low in the west after sunset around March and April. By June each year, this constellation is behind the sun as seen from Earth. Orion only returned to visibility in Earth’s sky about a month ago (see our July 29 sky chart). When a constellation becomes visible again, after being behind the sun, it always appears in the east before sunrise.

Because – as Earth orbits the sun – all the stars rise two hours earlier with each passing month, Orion is now higher at dawn than a month ago.

As seen from the Northern Hemisphere, Orion precedes Sirius the Dog Star into the sky. After Orion first appears at morning dawn, you can count on Sirius to appear in the morning sky a few weeks later. You should be able to see Sirius at or before dawn right now – unless you live at far northern latitudes. But even there, it won’t be much longer!

Bottom line: Every year in late August, look for Orion the Hunter and Sirius the Dog in the early morning sky! Orion’s three prominent Belt stars always point to Sirius.

Thursday, August 27th:


In both the evening and morning sky, try watching for Earth’s shadow. Earth’s shadow is a deep blue-grey, darker than the twilight sky. The pink band above the shadow – in the east after sunset, or west before dawn – is called the Belt of Venus.

Earth’s shadow can be seen any clear evening ascending in the eastern sky at the same rate that the sun sets below the western horizon.

The shadow of the Earth is big. You might have to turn your head to see the whole thing. And the shadow is curved, in just the same way that the whole Earth is curved. Earth’s shadow extends hundreds of thousands of miles into space, so far that it can touch the moon. Whenever that happens, there’s an eclipse of the moon, like the one coming up in September.

Check out Earth’s shadow – in the east at sunset or in the west at sunrise – next time you have a clear sky. I often see it while out on the streets of my town as the sun is setting.

By the way, the image at the top of this post shows more or less the same moon phase that you’ll see tonight. It’ll be a waxing gibbous moon that’ll be visible in the east after sunset this evening. The full moon will come on August 29, 2015, to present the first of this year’s full supermoons.

The basics: Watch for the curved blue-grey line of Earth’s shadow at dawn and dusk. The pink coloration above the shadow is called the Belt of Venus.

Friday, August 29th:


Supermoon ahead! The full moon of August 29, 2015 will be the first of this year’s three full supermoons. It’s a full moon near perigee, or near its closest point to Earth for the month. Like it or not, modern skylore dictates that these sorts of moons are called supermoons.

But will your eye see that the moon is bigger on the night of August 29? Well … it depends. Are you an incredibly careful observer? Have you watched the full moon over a period of months, leading up to now? If so you can discern the extra-large size of the supermoon using just your eye.

The closest and largest full supermoon of them all will fall on September 28, to stage a total eclipse of the moon. Some will call it a Blood Moon eclipse.

In North America, we often call the August full moon the Sturgeon Moon, Corn Moon or Grain Moon. The August 2015 full moon is also the first of three full-moon supermoons in 2015. Previously, we had three new moon supermoons in January, February and March, 2015. The full moons on August 29, September 28 and October 27 all enjoy the supermoon designation because the centers of these full moons and the center of Earth are less than 361,836 kilometers (224,834 miles) apart. The closest supermoon of the year comes with the September 28 full moon, presenting a moon that’s only 356,877 kilometers (221,753 miles) from Earth.

Super cool super-moonrise composite from Fiona M. Donnelly in Ontario. This was the supermoon of August, 2014.

Super cool super-moonrise composite from Fiona M. Donnelly in Ontario. This was the supermoon of August, 2014.

Details on the August, 2015 full supermoon The full moon falls at the same instant all over the world: August 29 at 18:35 Universal Time.

Clock time for this full moon – and every full moon – varies by time zone. For London, the moon turns full at 7:35 p.m. BST on August 29, at which time the afternoon sun shines in the west and the moon has not yet risen in the east. For the U.S., the moon turns full on at 1:35 p.m. CDT on August 29, when the sun shines way up high and the moon lies on the other side of the world, beneath our feet.

Technically speaking, the moon turns full at the instant that the moon lies most opposite the sun for the month. Because the moon stays more or less opposite the sun throughout the night, watch for a full-looking moon in the east at dusk, highest in the sky around midnight and low in the west at dawn. On the nights immediately before and after full moon, the moon still looks plenty full to the eye.

When is perigee, the moon’s closest point to Earth? In August, 2015, the moon’s perigee comes less than one day after full moon, on August 30 at 15:24 Universal Time.

The close coincidence of full moon and perigee makes this August full moon a supermoon.

By the way, no particular effects are expected from this extra-close full moon… unless you have the mass of an ocean! In that case, gravity will come into play. In other words, because it’s a supermoon, and relatively close to Earth, this month’s full moon will pull harder than usual on Earth’s oceans. Expect higher-than-usual tides to follow this full moon by a day or so. By the way, any full moon mirrors the sun’s path across the sky for six months hence.

And so here’s another cool thing you can notice about the August 29 full moon. As seen from the Northern Hemisphere, this full moon will follow the low path of the winter sun. As viewed from southerly latitudes, the moon will follow the lofty path of the summer sun.

Enjoy moon-watching tonight and in the next few evenings!

The basics: The full moon on August 29 ushers in the first of three full-moon supermoons in 2015. Full moon is August 29, 2015, at 18:35 Universal Time. The moon’s perigee or closest point comes on August 30, at 15:24 Universal Time.

Saturday, August 29th:


In North America, the August full moon is often called the Sturgeon Moon, Corn Moon or Grain Moon. Tonight – August 29, 2015 – if you’re in this hemisphere, it’s a super Sturgeon Moon you’ll see.

The full moons on August 29, September 28 and October 27 all enjoy supermoon status in 2015, because the centers of these full moons and the center of Earth are less than 361,836 kilometers (224,834 miles) apart. So it’s a super close full moon you’ll see on this night, dubbed, in modern skylore, a supermoon.

Some dislike the term supermoon, but I think it’s fun. But is it rare? No. We have three full supermoons this year, and we already had three new moon supermoons in January, February and March, 2015.

The closest supermoon of the year will arrive with the September 28, 2015 full moon. It’ll be only 356,877 kilometers (221,753 miles) from Earth.

Moreover, the closest and largest full supermoon of the year on September 28 will stage a total eclipse of the moon. This will be the fourth and final eclipse of a lunar tetrad – four total lunar eclipses in a row, each separated by six lunar months (full moons), with no partial lunar eclipse in between. Some refer to the four eclipses of a lunar tetrad as Blood Moons.

Technically speaking, North America won’t see the moon at the instant it turns full because it will happen during our daylight hours, when the moon is below our horizon and beneath our feet. The worldwide map below shows you the day and night sides of the world at the instant of the August 29 full moon (18:35 Universal Time). At United states time zones, that translates to 2:35 p.m. EDT, 1:35 p.m. CDT, 12:35 p.m. MDT or 11:35 a.m. PDT. You have to be on the nighttime side of the world to see the moon at the exact instant that it turns full.

Everyone around the word, however, will see a full-looking moon in the east at dusk or nightfall, highest up for the night around midnight and sitting low in the west at dawn. The moon stays more or less opposite the sun for the duration of the night on August 29, 2015.

The basics: the August full moon will be the Sturgeon Moon. if you’re in the North American hemisphere and this super Sturgeon Moon will be seen on August 29, 2015.

Happy viewing!




Astronomy: July’s Second Full Moon and Why You Should See It

Aside from the feeling of calmness that one could get while looking at the deep night sky, people may also witness the literal presentation of the popular folklore, "blue moon" on Friday, July 31.

Aside from the feeling of calmness that one could get while looking at the deep night sky, people may also witness the literal presentation of the popular folklore, “blue moon” on Friday, July 31.

‘Once in a Blue Moon’ typically means rare or absurd. This year, it means the end of July. The second full moon of July occurs on Friday. According to modern folklore, it’s a “Blue Moon.”

The early definition of the blue moon, as per The Maine Farmer’s Almanac, is the appearance of the third of four full moons in a season. But in the modern description, a blue moon pertains to the second full moon that appears in a single calendar month. Whatever the true definition is, “once in a blue moon” is used to mean “rare.”

In general, there is only one full moon in each calendar month or within a span of 30 days. This means that a blue moon is highly emphasized if the first full moon happened during the first 1-2 days of the month and the second full moon reappears after 30 days, which is still within the same month. The last full moon happened in July 2, making the July 31st full moon appearance as a “blue moon.” Blue moons appear once every 2-3 years and if the modern definition is to be consulted, the last blue moon happened on Aug. 31, 2012.

'Once in a blue moon' is literally happening on July 31 according to one of its two emerging definitions. Experts, however, say that the physical color of the moon may not actually resemble that of the vast ocean so set your expectations straight.

‘Once in a blue moon’ is literally happening on July 31 according to one of its two emerging definitions. Experts, however, say that the physical color of the moon may not actually resemble that of the vast ocean so set your expectations straight.

But the real question here is, “Is it really blue?” The experts think not. The date, period and time interval between the appearances of full moons do not have an effect on the color that the lunar object is likely to showcase. But why choose the color blue among all the other colors available in the spectrum?

According to early literature, people used to see moons that were indeed color blue in 1883. These moons were not specifically full; crescent or half-moons also exhibited the said color, making it a daily sight, except on rare occasions when it turns green. The main reason for this is the eruption of the Krakatoa volcano in Indonesia. The experts compared the said volcanic action to a 100-megaton nuclear bomb explosion.

People from nearly 400 miles were able to hear the eruption, ashes enveloped the sky massively and yes, the moon turned blue. The ashes contained particles that were able to scatter red light immensely and allow other colors to pass. The air had increased amounts of these particles that it turned the moon blue. For a bluer emphasis, the particles must be a little bit wider than the wavelength of red light. The white moonbeams glistening through the atmosphere turned blue and occasionally green.

Although numerous definitions of “blue moon” have emerged, it all points out to one thing: a blue moon is indeed rare and with its reported appearance at the end of the month, people could have another reason to look up in the sky as a new month begins.

Happy viewing!


Astronomy: The Week Ahead – Sun 28 Jun to Sat 4 Jul


Sunday June 28

Tonight’s waxing gibbous Moon is 11.8 days old and 90% illuminated. It is paired in tonight’s sky with Saturn, just over 2 degrees to its west. Both reside tonight in the constellation Libra. Below is Scorpius, with its brightest star Antares. Antares shines at magnitude 1.03, Saturn at 0.23, and the moon a brilliant magnitude -12.6!


Monday June 29

If you’re quick this morning, you’ll have another view of the planet Mercury, near Aldebaran in the constellation Taurus, just north of the eastern horizon.

There’s another interesting item in the sky to view though. The famous variable star Algol in Perseus is at its brightest, magnitude 2.0. Look at it this morning, then watch it over the next few dawns as it fades to 3rd magnitude, equal in brightness to the dimmer star to its right in this image.


Tuesday June 30

A spectacular conjunction occurs tonight, with the sky’s two brightest planets, Venus and Jupiter. They are so close together, the image here can’t show them as separate objects. You’ll be able to split them apart easily though, as they are 20 arcminutes apart. The diameter of the Moon is 30 arcminutes.

Look due west, an hour after sunset to see the pair, just below the sickle of Leo.


Wednesday July 1

If you have a clear western and eastern horizon you can watch Full Moon rising as the sun is setting. Try to do it! The Moon will be full in the constellation Sagittarius, above the asterism called the Teaspoon.

This is the summer’s first Full Moon, and was called the Full Buck Moon by Native Americans, as the bucks begin growing their antlers this month. Some called it the Thunder Moon, due to the frequency of thunderstorms in July.

July will have another full moon, so you’ll be able to see a Blue Moon this month too!


Thursday July 2

Morning skies in the east and southeast are beginning to show some of the water constellations. Cetus the whale. Pisces the fish. Aquarius the water carrier.


Friday July 3

The show continues in the west tonight, as Venus has moved clearly past Jupiter and the planets head toward a rendezvous with Regulus in Leo on the 14th. Have you even tried identifying some of the lesser known constellations around the famous Leo the Lion? Coma Berenices is behind its haunches. Leo Minor just over the mane of the big cat. Above them both, following the Great Bear (Ursa Major) and under the Big Dipper are the hunting dogs, Canes Venatici.


Saturday July 4

Here’s a celestial firework for the 4th of July. M13 is arguably the best globular cluster in the northern sky. It appears in a moderate size telescope much like a burst of star, or a firework. At magnitude 5.8, it is on edge of naked-eye visibility from a dark sky. It is large in apparent size, at 23 arcminutes (remember, the full moon is 30 arcminutes) and resides a full 25,100 light years away from earth, within our Milky Way galaxy, and is about 145 light years in diameter. Hard to imagine, this is a gravitational ball of several hundred thousand stars that are among the oldest (as globular clusters are) in the universe!

Happy viewing!


Astronomy: The Week Ahead – Sun 7 Jun to Sat 13 Jun

The recent appearance of the June Full Moon, aka the Strawberry Moon and the Rose Moon, signaled the final full moon of spring.

The recent appearance of the June Full Moon, aka the Strawberry Moon and the Rose Moon, signaled the final full moon of spring.


Sunday June 07

The morning Moon is at 74% illumination, waxing gibbous phase, in the constellation Aquarius. It is bright enough to wash out all but the brightest stars in the area. See if you can find these:

Beta Aquarrii (B) at magnitude 2.87

Delta Capricornus, magnitude 2.84


Monday June 08

Look how the Moon has moved since yesterday morning, deep into Aquarius and away from Capricornus. The constellation Capricornus is due south just before sunrise. Its “smile” shape is distinctive. Look closely at Alpha (A) Capricornus. It is an optical double star, with six arcseconds separation, much like Mizar and Alcor in the Big Dipper. Can you “split” them easily? This is an “optical” double, not a binary (two stars gravitationally bound together), with the A component 687 light years distant, the B star only 109 light years away.


Tuesday June 09

The Last Quarter Moon occurs today at 8:42 a.m. PDT. You can see it in the predawn sky in eastern Aquarius, approaching the washed out Circlet in Pisces.

The Last Quarter Moon begins a week of dark skies in the evening hours, as we approach New Moon. This lack of moon in the evening sky makes it prime time to hunt “faint fuzzy” objects, like nebulae and galaxies.


Wednesday June 10

Look to the east in the early evening and you’ll see bright Vega in the constellation Lyra, and Saturn low in Libra. Up above them is Arcturus, brightest stars in Bootes.

Bootes constellation shape is shown here, in the image. But it also has an asterism, a shape made by stars that is not a constellation. Look at the part of Bootes leaving off the two spurs that come off Arcturus to its right. What remains, to the left of and including Arcturus, is called The Kite, easily recognizable by its shape.


Thursday June 11

Tonight’s western horizon is graced by Venus and Jupiter as twilight deepens. These are the third and fourth brightest objects in our skies. What are the first and second brightest?

Tonight Venus shines magnitude -4.33, and it is 0.66 AU (1 AU = 93M miles) from Earth. Jupiter is much dimmer at magnitude -1.86, and 5.85 AU from us. Between them rides the orbital path of Mars and the asteroid belt!


Friday June 12

The Zodiacal constellation Libra is rising in the southeast in the early evening. It is easy to find as Saturn is currently in it, and bright Antares is just below Saturn.

Libra is the “Scales”, but in ancient times, it formed the claws of Scorpius the scorpion (of which, Antares is the heart). Libra is another constellation whose Alpha (A) star is dimmer than its Beta (B) star. Here are their names, magnitudes and distances:

A: Zubenelgenubi, 2.75, 77 LY

B: Zubeneschamali, 2.59, 160 LY


Saturday June 13

Libra contains on “bright” globular cluster. But don’t be fooled, this is dimmer than you might think. NGC 5897 has a bright magnitude of 8.4, but its ample size of 13 arcminutes spreads its light out, making it appear dimmer. It is close to the disk of the Milky Way and 40,000 light years away, so perhaps there is also dust obscuring our view.

Happy viewing!



Astronomy: The Week Ahead – Sun 31 May to Sat 6 Jun

Astro photography


Sunday May 31

Neptune is at western quadrature this at 05:52. Our chart is a bit earlier, to keep a dark sky. Find it in the southeast, between Fomalhaut in Pisces Australis, and Alpha (A) Aquaraii, Neptune can be hopped to off two naked eye stars, 1 and 2, magnitudes 4.2 and 3.7 respectively

Quadrature is when a planet is precisely between opposition and conjunction. Western quadrature puts a planet in the morning sky, eastern, the evening sky.

Neptune is small, at 2.3 arcseconds, and distinctly blue, at magnitude 7.80.


Monday June 1

Lyra is an easy constellation to identify constellation in the northeast, just as the sky darkens. Its alpha, or brightest, star is Vega, shining at magnitude 0.55, it is the second brightest stars in the northern sky, and fifth brightest overall. Along with Deneb in Cygnus, and Altair (not shown) in Aquila, it forms the Summer Triangle.

Lyra is easy to identify due to Vega’s brilliance, and the notable rectangular shape of the eastern part of the constellation. All four stars in the rectangle are double stars!


Tuesday June 2

The final Full Moon of spring occurred this morning at 09:20 PDT. But the moon will still appear full when it rises tonight in Ophiuchus at 20:30. Your local horizon may make moonrise appear later, if there is an obstruction such as trees, buildings or mountains.

This is the last full moon of spring, and is called the Strawberry Moon, or in Europe, the Rose Moon. At 3821,117 miles from earth, this is almost as distant as the moon can be. So, instead of a “super moon”, can we call it a “midget moon”?


Wednesday June 3

Will this be the last of Jupiter’s double shadow transits of this apparition?

Io’s shadow begins before its dark, at 20:54, and ends at 23:15. Ganymede starts at 21:51 and ends after Jupiter sets, at 01:41 on 6/4.

Grab your telescope and see if you can tell the difference in shadow sizes, and watch how quickly Io’s smaller shadow transits the planet compared to Ganymede’s.

Also, enjoy the nice unaided view of Jupiter and Venus in the darkening western sky.


Thursday June 4

Look to the southwest an hour before sunrise and see Saturn about to set. The planet rises at sunset, and sets at sunrise, having just passed opposition.

Our morning constellation this week is Ophiuchus, directly over the ringed planet. It is large and mostly rectangular, with a nice line of four stars forming its lower boundary in this view. Its brightest, or alpha star is Rasalhague, high atop the constellation, shining at magnitude 2, and only 47 light years from our sun. Ophiuchus contains more globular clusters than any other constellation.


Friday June 5

Venus reached it greatest elongation today at 15:09, PDT. While at its farthest position in the sky from the sun, it forms a stunning pair with Jupiter, our two brightest planets. Nearby Venus is Castor and Pollux in Gemini, and Procyon in Canis Minor. Jupiter is west of Leo’s brightest stars Regulus. Between them, unlabeled, is the dim constellation Cancer.


Saturday June 6

Let’s have some fun with a nice morning double star. On Thursday I mentioned Rasalhague as the alpha star in Ophiuchus. Today, its neighbor in our sky, Rasalgethi, is the alpha star of Hercules. Even their names seem similar.

Rasalgethi can be split in most telescopes, with a separation of 4.6 arcseconds. Its primary component is a variable, ranging from magnitude 3.0 to 4.0, and yellow color. Its companion is a white-yellow dwarf at magnitude 5.4. The pair are about 360 light years away, and appear to shine at magnitude 2.75. If the primary component were placed where our sun is, it would extend past the orbit of Mars.

Happy viewing!


Astronomy: The Week Ahead – Sun 03 May to Sat 09 May


Sunday May 03

Tonight is a planetary show! The moon is full at 20:42 PDT. This full moon’s names are Full Flower Moon, Full Corn Planting Moon or Milk Moon. It is the season of abundance. Watch it rising in the east as the sky darkens, followed by Saturn in an hour eighteen degrees east. Look west in the darkening twilight to find Jupiter high above brilliant Venus low to the west, and Mercury skimming the horizon below Venus to the right. Spring has just one more full moon, then summer observing season begin!


Monday May 04

Jupiter was at Eastern Quadrature at 1:44 a.m. today, at a right angle to the sun from the earth. Jupiter observing season is quickly coming to a close for 2015. Tonight you can enjoy the last part of a shadow transit of Io, and a view of the Great Red Spot (GRS) as the giant planet slides toward the western horizon and sunset. Don’t wait till it’s dark, or the shadow transit will be over.


Tuesday May 05

Rising in the east on early May mornings is the constellation Pegasus, the Winged Horse. Its famous asterism, The Great Square, is marked on its corners by the bright stars Alpheratz, Algenib, Markab and Scheat. Trailing off the northern corner star Alpheratz is a pair of star chains, defining another famous constellation, which shares Pegasus’ star Alpheratz.


Wednesday May 06

Mercury is at its greatest elongation tonight during sunset at 20:30 PDT. Occasionally the universe puts on a beautiful celestial show, and tonight is such an evening, with Orion bidding us adieu sinking into the sunset for another season, Mercury, Venus and Jupiter forming an ascending display rising toward nightfall. Go out and enjoy this excellent view!


Thursday May 07

Galaxy season is well upon us, with Downtown Virgo being where the action is. Located between the stars Vindemiatrix in Virgo, and Denebola in Leo, M84 and M86 are central in the Virgo Galaxy Cluster, approximately 45 million light years distant. Get yourself to a darker sky, set up your telescope and enjoy the show. You’ll find yourself galaxy hopping, instead of star hopping, in this busy part of the sky!


Friday May 08

Tonight Venus is in conjunction with the great open cluster M35 in Gemini. At less than two degrees separation, they will fit easily in a binocular field of view. If you have a wide field eyepiece, they should form a spectacular pair together at low magnification. Don’t forget to peek for Mercury too, skimming the western horizon as twilight darkens.


Saturday May 09

Look for Hercules and Ophiuchus in the predawn skies today. Their Alpha (brightest) stars sit very close together in our sky, and they share similar Arabic names. Rasalhague shines at magnitude 2.1, and is only 47 light years distant, truly a neighbor of ours. Rasalgethi is dimmer, at 2.75, and much more remote at distance of 384 light years. Rasalgethi is also an excellent double star in a telescope. The primary is a variable star, ranging from magnitude 3.0 to 4.0. Its companion is separated by 4.6 arcseconds – resolvable in most telescopes, shining at magnitude 5.4. They orbit each other over a 3600 years period.

Happy viewing!


Astronomy: The March Full Moon – Worm, Crow, Sap, Crust & Lenten Moons

crow moon

If you’re into multiple names for the full moon, then March’s moon is the one for you!

March’s full moon arrives full of promise for an early spring in America’s lower 48 on March 5, 1:05 pm eastern time.

The Native American full moon names for March are largely based on these being considered the last full moons of winter: the crow caws its farewell to the season and worms start to surface at this time, signaling the retreat of winter and the marching in of springtime.

The more northern tribes knew this Moon as the Full Crow Moon, when the cawing of crows signaled the end of winter; or the Full Crust Moon, because the snow cover becomes crusted from thawing by day and freezing at night. The Full Sap Moon, marking the time of tapping maple trees, is another variation. To the settlers, it was also known as the Lenten Moon, and was considered to be the last full Moon of winter. The name Storm Moon comes from weather folklore, it is said to occur during shifting weather patterns in the northern hemisphere.

Other names include Sugar or Sugaring Moon, Chaste Moon, Death Moon, Seed Moon, Moon of the Winds, Moon of the Snow Blind.



Astronomy – The Week Ahead: Sun 1 Feb thru Sat 7 Feb

feb 1

Sunday February 1

Tonight features two planets. Venus is at 23.8° E of the sun, brilliant in the western sky, outshining Mars nearby in Aquarius. On the eastern horizon Jupiter is rising almost concurrent with sunset. Its moon Io is showing a Shadow Transit as it rises. It will end at 19:15. You can watch the black spot approach and then leave the limb of Jupiter, followed seven minutes later by Io itself. But keep watching, as Io moves off the planet and Europa swings toward the backside into an eclipse. The fun part is that Io and Europa will “merge” as Io passes in front, just as Europa disappears into Jupiter’s shadow at 19:32!


Monday February 2

The Summer Triangle, comprised of Deneb, Vega and Altair, are up in the east before sunrise. This famous asterism is easy to see, with Altair directly over the eastern horizon. Look for the Milky Way: it stretches most obviously through Cygnus, Aquila and Scutum. Many people mistake it for clouds over the horizon.


Tuesday February 3

Today is February’s Full Moon arriving at 6:09 pm eastern time. It is called Full Snow Moon or Full Hunger Moon by Native American tribes, for the year’s heaviest snow and difficulty hunting.

Other Native American tribes called this Moon the “Shoulder to Shoulder Around the Fire Moon” (Wishram Native Americans), the “No Snow in the Trails Moon” (Zuni Native Americans), and the “Bone Moon” (Cherokee Native Americans). The Bone Moon meant that there was so little food that people gnawed on bones and ate bone marrow soup.

The Moon will be paired nicely with Jupiter, between Leo and Cancer, both rising within minutes of each other. The Moon will be in the sky all night, Jupiter, almost all night.

Moon Fact: 2,160 miles in diameter, less than the width of the United States.

feb 4

Wednesday February 4

Epsilon Lyrae is a famous multiple star system, 161 light years from us in the constellation Lyra. It is commonly referred to as The Double Double, since it is comprised of a pair of double stars in close proximity to each other.

The un-split pairs shine at a combined magnitude 4.5, so they are easy to see near Lyra’s bright star Vega. Sharp eyes in excellent conditions can split the main pair into two stars 3.5 arc-minutes apart. Through a telescope, those two split each into their own, with separations of 2.3 and 2.6 arc seconds.


Thursday February 5

The Moon forms a nice pair with Leo’s brightest star Regulus all night and through sunrise today, with Jupiter nearby. The Moon is at apogee today, 406,200 km from earth. Apogee is the farthest point the Moon reaches in its lunar monthly orbit around the earth. A Full Moon at apogee is the opposite of the recently popularized “Super Moon”. Maybe we should coin the term “Mini-Moon” to describe this? Today’s moon is not full, but at a 16.2-day-old waning gibbous phase, 98% illuminated.


Friday February 6

Jupiter is at opposition today. Opposition is an astronomical term that means the Earth is directly between the Sun and a planet. This can only occur with the outer planets. Inner planets have conjunctions, both inferior and superior.

We are at our closest point to Jupiter for 2015, so is at it largest size for the year today at 45 arc-seconds. Since Jupiter is opposite us from the sun today, it will rise exactly at sunset, and set exactly at sunrise.


Saturday February 7

Gemini is up nicely early in the evening, giving us a great opportunity to enjoy views of the Eskimo Nebula, NGC 2392. While telescopes will not show the clarity of this image, a double shell structure and darker inner ring can clearly be seen around a 9th magnitude central star. In a low power view, note the color difference between the “fuzzy star” and the neighboring 8th magnitude star. See a greenish tint? This is a planetary nebula, a star blowing off layers of atmosphere toward the end of its life. NGC 2392 shines at magnitude 10, subtends 42 arc-seconds (the size of Jupiter), and is over 2870 light years away.

Happy viewing!


Astronomy: The Week Ahead – Sun 26 Jan to Sat 31 Jan


Sunday January 25

Here is a view of tonight at 8 p.m. via PST. The Moon is between the constellations Gemini and Cancer. Notice the two circles, one inside the other, near the center of Cancer. If you know what they are then you’ll also know they are always present, can be seen visually, and are constantly in motion.


Monday January 26

Today the Moon reaches its First Quarter phase. Moon phases begin at New Moon, when the Moon is too close to the Sun to be viewed. The lunar month begins with waxing crescent, waxing meaning getting (visually) larger. Today it changes from crescent to gibbous; over half the Moon illuminated by the Sun. After Full Moon, it begins waning, and is less illuminated each night. The waning gibbous Moon changes to a waning crescent as it passes through Third Quarter, as it continues on toward the next New Moon.

Also, on Monday evening January 26th, it will become the largest asteroid to pass closest to Earth until 2027 when 1999 AN10 will approach within one lunar distance. (See:  Astronomy: Big Asteroid 2004 BL86 Buzzes Earth on Monday 26 January)


Tuesday January 27

Morning observers can find the Sunflower Galaxy, M63 high in the northwest, in the constellation Canes Venatici, the Hunting Dogs. Using the constellation’s one bright star, Cor Caroli (The Heart of Charles), and the end star of The Big Dipper as reference points, it is easy to star hop to.

The galaxy is bright at magnitude 8.6, and will be visible from darker locations in binoculars and any telescope. It will appear elongated and containing a bright core. It is part of the same galaxy group at M51, The Whirlpool Galaxy, and at a distance of about 35 million light years.


Wednesday January 28

This morning before sunrise look for the constellation Serpens Caput in the southwestern skies. It will be directly above Saturn. An easy way to find it is along the line of stars the define the lower part of Ophiuchus, as they point to Serpens Caput’s brightest star, Unukalhai, which is a double star. The name Unukalhai translates from Arabic as “The neck of the serpent”. It is also called Cor Serpentis, the heart of the serpent.

Serpens is broken into two parts, on opposite sides of Ophiuchus, the Serpent Bearer in Greek mythology. Caput is on the western side and Cauda to the east.


Thursday January 29

An hour after sunset you can see Jupiter rising near the eastern horizon, and a bright waxing gibbous Moon in Taurus near Aldebaran. Note the green line crossing upward from near Jupiter. It is the ecliptic, the path of the sun through our skies. Constellations along the ecliptic are the signs of the Zodiac.

The Moon and planets follow the ecliptic, but wander north and south of the sun’s path. The Moon tonight is south of the ecliptics, Jupiter slightly to its north.


Friday January 30

With a large bright Moon in the sky, near Orion and Gemini, let’s look away, to the north for a nice bright target.

M103 is a beautiful small jewel of an open star cluster, in Cassiopeia. Even binoculars will reveal its three brightst stars, magnitudes 7 and 8, in an almost straight line, with hints of nebulosity. Overall, it is bright (magnitude 7.4) and small, occupying only 6 arc-minutes, and rich. One experienced observer counted 28 stars in the cluster in a 13″ telescope, noting a nice chain of of 10th magnitude stars along its northeast side.


Saturday January 31

Tonight Jupiter treats us to two very good shadow transits, with interesting timing! Start by finding the Great Red Spot near meridian at 22:26 PST. Two minutes later Io’s shadow begins ingress on Jupiter’s disk. The Moon itself will ingress ten minutes later. Io’s shadow will end its transit at 00:45, and Io at 00:56. In another seven minutes you’ll see Europa’s shadow transit begin.

Happy viewing!


Astronomy: Behold The Wolf Moon

wolf moon

Tonight, the moon is full.

This full moon falls on January 5, 2015 at 4:53 Universal Time. Although the moon turns full at the same instant worldwide, the clock time – and possibly the date – differs by time zone. For the mainland United States, the moon reaches the crest of its full phase on this Sunday evening on January 4 at 11:53 p.m. EST, 10:53 p.m. CST, 9:53 p.m. MST or 8:53 p.m. PST.

Day and night sides of Earth at the instant of the January 2015 full moon (2015 January 5 at 4:53 UTC) Image via Earthview

Day and night sides of Earth at the instant of the January 2015 full moon (2015 January 5 at 4:53 UTC) Image via Earthview

The January 2015 full moon is the first full moon after the December 21 solstice. In North America, we often call this full moon the Wolf Moon, Old Moon or Moon After Yule.

Astronomically speaking, the moon is full at the moment that it’s most opposite the sun in its orbit (180o from the sun in celestial or ecliptic longitude). For general reference, however, we can say the moon is full all night tonight, lighting up the nighttime from dusk until dawn.

Elsewhere around the world, the moon reaches the crest of its full phase at different times on the clock. Looking at the worldwide map above, you can see that the full moon comes at midnight in South America and northeastern North America, at sunrise in Africa and the Middle East and at noon in eastern Asia. All these places will see a full-looking moon lighting up the sky tonight from dusk until dawn.

But to see the moon at the instant of full moon, the moon has to be above your horizon on the nighttime side of the world.

In both the Northern and Southern Hemispheres, the January sun – unlike the January full moon – rises south of due east and sets south of due west. In the Northern Hemisphere, these far-southern risings and settings of the sun give us the short days of winter. South of the equator, the same far-southern sunrises and sunsets bring long summer days. Meanwhile, the full moon lies opposite the sun, mirroring the sun’s place in front of the backdrop stars for six months hence.

full wolf moon

And that’s why tonight’s moon – like the sun in summer – will follow a high path across the sky as seen from the northern part of the globe – and a low path as seen from the southern.

This January full moon rises north of due east around sunset, climbs highest in the sky around midnight and sets north of due west around sunrise.

Bottom line: Watch the full moon shine from sundown to sunup on the night of January 4, 2015.

Meanwhile, the Quadrantid meteor shower continues tonight – peaking from now until Monday night.

Happy viewing!