AMATEUR ASTRONOMY:
TRIPLE PLAY IN THE MORNING SKY:


Assuming you get up before the Sun does, which isn't hard this time of year, there is an interesting sight in the eastern sky. Given good conditions the three planets Mercury, Venus and Saturn will be visible at the same time. Here's the story from that great site Space.com.
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Planet Triple Feature:
Venus, Saturn and Mercury Visible at Dawn This Week
By Geoff Gaherty
Early risers this week will be treated to a spectacular display of planets and bright stars as Venus, Mercury and Saturn take center stage in the predawn sky.

Half an hour before sunrise, three of the brightest planets will stretch across the eastern sky, further enhanced by the presence of two first magnitude stars, blue-white Spica and deep red Antares.

The sky map above shows how Mercury, Venus and Saturn will appear before sunrise in the eastern and southeastern sky.

The first object to attract your attention will be the planet Venus, outshining everything in the sky except the sun and moon. In a small telescope, Venus will appear as a tiny half moon as it approaches its greatest apparent distance from the sun on Saturday, Jan. 8.

Second in brightness will be the elusive planet Mercury, well below and to the left of Venus, close to the horizon. Do not confuse it with the red giant star Antares, almost directly below Venus.

You may need binoculars to spot Mercury in the bright dawn sky. This is not a favorable apparition of Mercury because of the shallow angle that the ecliptic (the path of the sun through the sky) makes with the horizon. Mercury also appears in a telescope as a tiny half moon, with the greatest elongation being on Sunday, Jan. 9.

Finally, above and to the right of Venus rides the planet Saturn, and, just below it, the brightest star in the constellation Virgo: Spica. In a telescope magnifying more than 25 times you should be able to see Saturn's famous rings, although magnification of around 200 times is needed to see the details.

Whenever you view Saturn in a telescope, be on the lookout for its retinue of moons. Even the smallest telescope will show its largest moon Titan, and larger telescopes will show half a dozen more.

AMATEUR ASTRONOMY:

TOTAL LUNAR ECLIPSE WINNIPEG: ENTRY NUMBER 8:

Just as a little sign-off here...It's now about 12:35 am on the morning of February 21. The eclipse is long over, and Saturn and Regulus are now in their "proper" places as per the references I quoted before. Saturn is above and to the left of the Moon. Regulus is to the right and above. I guess that the references didn't take take account of the time and merely quoted the position at midnight. Well, that's one mystery solved. Time to sign off for the night. sweet dreams to all... Molly.

AMATEUR ASTRONOMY:

LUNAR ECLIPSE FEBRUARY 20: ONE MORE DAY TO GO:

As has been previously mentioned, the last total eclipse of the Moon visible from North America until 2010 will be coming up tomorrow night. Here in Central Standard Time the partial eclipse will begin at 19:43, the total eclipse will begin at 21:01 and end at 21:50, and the partial eclipse will end at 23:08. See previous posts on this blog in our archives for January and February of this year (search 'Lunar eclipse') for more on the timing and how to convert to your own time zone.

VIEWING CONDITIONS:

The Environment Canada weather office site predicts clear conditions for tomorrow and the day after. You can check the general weather forecast for your area from this source if you live in Canada. For a more detailed forecast look to the Clear Dark Sky site. Molly has added a widgit of this site for the Winnipeg area near the bottom of our Links section. It is the strange looking hatched coloured bar. This forecast, much more detailed than that from Environment Canada, unfortunately predicts less than ideal viewing conditions here in Winnipeg tomorrow night. Up to 60% cloud cover (one hopes mainly in the West) and "poor" "seeing conditions". We'll just have to wait and see, no pun intended. I'll update the forecast tomorrow. The Clear Dark Sky site provides detailed atmospheric forecasts for many dozens of sites across the North American continent, not just Canada.

OTHER THINGS TO WATCH FOR:

There are a few other things to look for during the upcoming eclipse. I have already mentioned that the planet Saturn will be prominent above and to the left of the Moon during the eclipse period tomorrow. On the other side, to the right, will be the star Regulus. This is the most prominent star in the constellation of Leo (see this blog for May 13, 2007 for a discussion of 'The Constellation Leo')., and it forms the base of the "sickle" that defines the head of the lion that is Leo. it is the 21st brightest star in the sky, at an apparent magnitude of 1.35. During this eclipse Saturn and Regulus will bracket the Moon. Because it is positioned on the ecliptic Regulus is routinely occulted by the Moon, and rarely by other planets. There will be three occultations of Regulus this year, on February 21, March 19 and April 15. All of them, however, will only be visible from parts of the southern hemisphere. If you have an interest in occulatations Molly advises you to look up the International Occulation Timing Association website. There's a wealth of information there. For other interesting astronomical events in the upcoming week tune in to the Weekly Stargazing Tips on Star Date Online. The Leonid Meteor showers, by the way, are sometimes the most dramatic of the meteor showers in a year. This year they are due on the morning of November 17.

AMATEUR ASTRONOMY:

UPCOMING CONJUNCTION OCTOBER 7TH:

Look east between 5:00 am and 7:00 am this coming Sunday, October 7th to see an impressive sight. The waning crescent Moon will sit just below and a tiny bit to the right of the planet Saturn. A little bit further to the right and a bit towards the zenith the planet Venus will also be within a regular 7 degrees binocular field, along with the star Regulus in the constellation Leo. All these bright objects will come together at this time for a spectacular show. Venus, now the "morning star", reached it greatest magnitude on September 23rd, but it is still very bright in the morning sky. On October 14th and 15th Venus and Saturn will make their closest approach, being within 3 degrees of each other just slightly below Regulus.

A FIVE PLANET PARADE:

Through this early part of June the five visible planets will be observable.

VENUS:

Even though Venus reaches its greatest elongation (distance from the sun) this Saturday the planet is already rising less and less in the evening sky each night. The planet is presently located at the crossover from Gemini to Cancer and shines with a bright magnitude 0f -4.4. Venus is the second brightest object in the night sky after the Moon. The planet is presently at a waning half phase and as it enters its waning crescent phase in early July the apparent size of the disc will double from is apparent size as of May 1st. As the crescent of Venus gets thinner and thinner by late July, early August, it will have grown from an apparent size of 16 arc seconds on May 1st to 50 arc seconds.

The end of this month will see a brilliant conjunction on the evening of June 30th when Venus and Saturn pass within 2/3rds of a degree of each other. This will be the closest planetary conjunction of the year and will be best viewed due west between 10pm and 11pm that evening. The two planets will be close enough to be both visible in the eyepiece of a moderate power telescope.

MERCURY:

Though it is presently sinking towards the horizon Mercury is still visible in the western twilight until mid-June. it passed its greatest elongation on June 1st when it shone with a magnitude of +0.4. It now is about +1.2 in magnitude. From 10pm to 11pm for the next few days Mercury can be seen very low in the northwestern sky, to the right and below Venus.

SATURN

As said above Saturn will pass in conjunction with Venus on the evening of June 30th. Saturn is in the constellations Leo , to the east of the position of Venus. Saturn is presently setting before midnight, and it will set earlier and earlier as the month goes on. even though the rings present a good view because of a 17 degree tilt the features of the planet will be less and less visible as the month goes on because the closeness of the horizon will blur the detail. Presently Saturn shines at magnitude +0.5.

JUPITER:

The planet Jupiter is now much brighter than Saturn at magnitude -2.6. This planet reached opposition on June 5th when it began to rise just as the sun set. You will find it in the southeastern to southern sky throughout the nights in the constellation Ophiuchus. This constellation lays on and just above the ecliptic between the constellations of Libra to the west and Sagittarius to the east. Jupiter is usually the second brightest planet after Venus. Its distance from Earth is compensated by the fact that its surface area is 130 times that of Venus. Jupiter will never rise too high in the sky this month(20 degrees elevation at max, and that makes telescopic viewing difficult. Early next Saturday morning here in western North America two of Jupiter's Galilean moons will cast their shadows on the planet's face at the same time. Depending on location this will occur anywhere from 2:17 to 3:03 am this Saturday. This will be a good time for telescopic observation of this planet.

MARS:

This month the planet Mars can be observed at +0.8 magnitude in the constellation Pisces. This means that it lays low in the east in the hours just before sunrise. Mars is presently just to the east of the waning crescent Moon in the hours before dawn, but by June 11th it will have passed to the west, rising earlier and higher throughout the summer.

OCCULTATION OF SATURN AND THE STARS OF GEMINI:

The Moon, now in its first quarter has moved out of the constellation Gemini and is now entering Leo via the very dim constellation of Cancer (hardly visible at all except in the clearest skies) When you look up tonight you can see the Moon separated by only about 2 or 3 degrees from Saturn which now lie just to the west of Regulus, the star that marks the beginning of the "hook" in Leo. Saturn is actually quite good for viewing at this time as its rings have a 15 degree tilt, and are quite visible. Tomorrow (april 25th), however, may be even better as the Moon and Saturn will reach their closest approach. In Northern Canada, Alaska, the west coast of Canada and the upper north west of the USA there will actually be an occultation of Saturn by the Moon. The occultation will occur at about 10:28 UT in Vancouver and at about 10:30 UT in Victoria BC. This translates to a local time of about 2:40 am in Victoria. In Edmonton Alberta it will begin slightly earlier, at 10:17 UT. Go to the Lunar Occulatations site for further information.

As long as the Moon is leaving Gemini it's perhaps time to visit the stars of this constellation. Refer to the above diagram for what follows, and imagine it as being rotated 90 degrees counterclockwise so that Castor is higher in the sky than its brighter companion Pollux. The above diagram, however, better illustrates how this constellation resembles two stick men side by side, the "twins". The apparent orientation of Gemini changes throughout the year. Presently it is gradually returning from a "left" rotation, and it will gradually become more horizontal until it is no longer visible come the month of June. When it returns in the late fall it will considerably rotated "clockwise". At that time one of the stars is within the Milky Way and one is outside of it. This is connected with the legend of "cattle theft" associated with this constellation (see later).

The twins are called the Dioskouroi in Greek mythology, meaning "youths of Zeus (the god), and Pollux is often referred to as 'Polydeuces'. The Greek legends probably derive from more ancient Indo-European myths as the twin horsemen, the Asvins, occur in the Vedas and the Alcis twins figure in Germanic mythology. In Rome they were sometimes confused with Romulus and Remus. In China, on the other hand, these stars are associated with the yin and yang of nature. The twins in such legends are usually depicted as unequal. Another Greek example of such a configuration is the Ampion/Zethus pair from Thebes. Various versions of the Greek legends exist. Sometimes both twins are immortal, sometimes neither and sometimes only one. If only one it is Pollux/Polydeuces who is the immortal one. The most common legend is that Zeus, disguised as a swan, seduced their mother Leda, and that the two brothers were born from eggs. The representations of the Dioscuri in vase painting feature skullcaps that are said to be remanants of the eggs.

In some versions Tyndareus, King of Sparta, is merely their step father. In others he is the father of Castor but not of Polydeucis. Their sisters were Helen of Troy and Clytemnestra. They were reportedly brought up by the centaur Chiron(represented by the constellation Centaurs), and later they joined Jason, who was also reportedly brought up by Chiron, in the quest for the Golden Fleece. They also were said to have rescued their sister Helen when she was carried off by Theseus and Pirithous. Seems like Helen tried more than once to get out of Sparta. The twins had a general connection to Sparta, and their duality was reflected in the two kings of Spartan government. Their grave shrine was at Therapne, across the Eurotas River from Sparta.

The Dioscuri met their match in the twin brothers of Thebes, Idas and Lynceus, when Castor and Polydeuces abducted the daughters of Leucippus, Phoebe and Hilaeira, known as the Leucippides ("white horses"). Seems the Greeks did a lot of kidnapping. Castor was supposedly killed in this encounter, and his brother pleaded with Zeus to grant him half his immortality. From that time forward each twin spent alternating days on Olympus and in Hades. Thus they weren't present at the siege of Troy. When the constellation is rotated clockwise it appears as if one of the twins is "stealing the cattle" from the Milky Way while the other looks on. Castor and Polydeucis are considered the patrons of mariners because of their role in calming a storm during the voyage of the Argo.

The two brightest stars of Gemini are Castor (now higher than Pollux) and Pollux. Pollux is the brightest at a magnitude of 1.1. It is an orange star that lies at a distance of 36 light years (lys). Castor is the second brightest at magnitude 1.6. It is a blue white star at a distance of 46 lys. It is actually a septuplet, and the individual stars have far lesser magnitudes than the combined brightness of the naked eye object. Mebutsa (on the upper arm of Gemini, going west comes from the Arabic for "lion's paw", but the name is only recent. it is a yellow white star of magnitude 3.0 and lies 685 lys away. Going further to the west we come to Tejat, and orange red star of magnitude 2.9 that lies 150 light years away. On the lower arm of Gemini we find Wasat, meaning "the middle" in Arabic, another recent name. It is a whitish double star of magnitude 3.5 (the brighter of the pair) and is 58 light years away. The now demoted "planet" Pluto was found close to this star in 1930. Further to the west is Mekbuda, which also means "lion's paw". It is a yellow white variable star with magnitude 3.7 to 4.2 every 10 days. It is 1,400 lys away. Then at the furthest west we come to Alhena meaning "mark on the neck of a camel". It is a blue white star of magnitude 1.9 and is about 85 lys away. One named star not shown in the above diagram is Propus, the "forward foot" of Castor. It is a little to the west of Tejat. It is an orange red variable star (magnitude 3 to 4 over 233 days), and is about 185 light years away.

The reader should note that the magnitudes listed above are "inverse". The smaller the number the greater the apparent brightness. In a city sky pretty well all that can be seen of Gemini is Castor and Pollux. On an exceptionally clear night some of the other stars named above can be visualized.

LAST CHANCE FOR THE WINTER HUNTER:

THE STARS OF ORION:

Last night Molly observed a beautiful sight. In the early evening the waxing crescent Moon and Venus were present together in the southwest sky, with a separation of less than 5 degrees. Venus has been gradually brightening this month, from a magnitude of -4.02 at the beginning of April. It will continue to brighten to -4.11 by the end of April. Venus shines brightest when it is in a crescent phase. Yesterday the globe of the Moon was plainly outlined, even it dark portions. The star Aldebaran in the constellation Taurus was shining a rusty red to their left, and the Pleiades were visible to the lower right of the Moon. Capella was a bright star higher in the sky to the right (north). Tonight Venus will appear beneath the crescent Moon (yesterday it was to the right/south), but the sky conditions here in Winnipeg are such that Molly will probably not be able to view this event. As a side note Saturn (see previous posts on this blog) was plainly visible almost due south just down from the "hook" of the constellation Leo.

Anyways, at the time of viewing Orion was low in the southwest. Soon it will no longer be visible as spring springs more fully. This is the last chance to observe the stars of Orion the Hunter before he departs until the fall. Please refer to the graphic above for what follows: a mini-tour of the sights of Orion. Orion is a constellation visible in both the northern and southern hemispheres (though the appearance differs). In Australia the "belt" of Orion is often referred to as "the saucepan". Orion's belt is also called "the three kings" in some places. In Sumeria this constellation was referred to as "The Shepherd of Anu". In ancient Egypt this constellation was associated with Osiris, the god of the underworld. The Greek mythology of Orion the Hunter, however, is that which has penetrated most deeply into popular western culture. Orion figures in works of literature from 'Paradise Lost' , Tennyson, Tolkien and numerous other books, comics, musical works to Star Trek and Stargate,Atlantis. Orion has also figured in native American and Australian aborigine mythology. In Norse mythology Orion's belt was known as 'Frigg's distaff'. The Bible mentions Orion 3 times (Job 9:9, Job 38:31, Amos 5:8). The Greek myths generally revolve around the goddess Artemis falling in love with the hunter Orion. She was apparently so entranced that she forgot her duty of illuminating the night sky (Artemis was a Moon goddess). Her twin brother Apollo supposedly saw Orion swimming in the sea and dared his sister to hit what seemed to be only a spot on the horizon with her bow. Artemis, being more accurate than the US military, "hit the spot". When she found what she had done she placed his body in the sky. This apparently explains why the "face in the Moon" looks sad. A variant ending to the myth is that Apollo summoned a giant scorpion (the constellation Scorpio) which stung Orion to death. The result was that Scorpio and Orion could never appear together in the sky. Scorpio is a summer constellation.

Look to the illustration above. The two most prominent stars are Rigel at the lower right and Betelgeuse at the upper left.Betelgeuse is a red giant (the colour is apparent to the naked eye as a yellow orange) with an diameter probably larger than the orbit of Mars. It is an irregular pulsar that varies from 0.3 to 0.6 in magnitude. It is somewhat dimmer than Rigel, a large blue white star. Rigel at 0.1 magnitude is one of the brightest stars in the sky. Rigel has three stellar companions invisible to the naked eye. The star Bellatrix is the apparent "left shoulder" or Orion in the diagram (to the right of the viewer actually). The star Saiph is at the lower left of the rectangle that describes the main part of Orion. The "head" of Orion is Meissa, just above a line drawn from Bellatrix to Betelgeuse. The three stars of Orion's belt are named (from right to left) Mintaka, Alnilam and Alnitak. Just below this is the "sword of Orion". The "tip" os Orion's sword is the star Hatsya. In this are one may see a faint blurry area that is the famous Orion Nebula (M 42). this overlaps with a multiple star system called the Trapezium. The famous Horsehead Nebula is just below the leftmost star, Alnitak, in Orion's belt.

Orion can be used as a celestial landmark to find many other stars and constellations. Sirius, the brightest star in the night sky can be found by drawing a line to the left from the belt of Orion. Aldebaron, the "eye of Taurus", can be found by drawing a line rightward through the shoulders. A diagonal line from Rigel through Betelgeuse leads you to Castor and Pollux in the constellation Gemini. A line drawn leftward through the shoulders leads you to Procyon , another bright star in Canis Minor. Sirius is in Canis Major.

Molly

SATURN SPOTTING:

The planet Saturn is presently making one of its retrograde motions and passing from the constellation of Leo westward to the faint constellation of Cancer. It previously passed to Leo from cancer last fall in Sept and Oct.. Looking down the alley from her city location Molly cannot distinguish any of the stars of Cancer, but she can easily make out most of the stars of Leo and at least Castor, Pollux, Tejat and Alhena in Gemini (the constellation immediately to the west of Cancer). Saturn is about 15 degrees to the west of Algiebra(the second star in the "hook" of Leo, and a bit further towards the zenith than the bright star Regulus (the beginning of the "hook"). Viewing is a bit restricted because of the light of the first quarter Moon. Tonight, at about 11:00 pm Central Standard Time, Leo and Saturn are a bit to the east of due south. Orion has begun to advance towards the horizon in the southwest. Sirius, the brightest star in the sky, is almost due south.

For further information on the planet Saturn go to the Wikipedia article and the Nine Planets site. The two sites complement each other.

A little interesting Saturn factoid. The actual length of a Saturnian day is uncertain. The gaseous nature of the planet leaves no firm "handle" to measure the period of rotation. Astronomers have relied on radio measurements of the planet's magnetic field to make their estimates, but recent findings have shown that geyser activity on the small Saturnian moon Encaledus inhibits the rotation of the planet's magnetic field to a speed less than that of the actual rotation. The most recent measurements place Saturn's "day" as about 10 hours and 47 minutes. Interestingly enough comparative measurements have shown that this is about 6 to 8 minutes longer than the time Saturn took to rotate in the 1980s when the first measurements were taken.

Anyways, more on Saturn, Leo and the other constellations mentioned later.

Molly