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The Sky This Month - October 2006

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Written by Gary Boyle, Ottawa on
Post Date: 
Wed, 2006/10/04

October is well known for its wet weather. Cold, damp days are a sure indication winter is slowly creeping in. With this in mind, we will focus this month’s article on the watery constellation namely Aquarius – the Water Bearer and Pisces – the Fishes.

Reflecting back to the 1970s, the musical group “Fifth Dimension” released a hit song named the “Age of Aquarius. The song starts off with, “When the moon is in the seventh house and Jupiter aligns with Mars, and peace will guide the planets…” you get the picture. Well Jupiter and Mars are pretty well consumed in the Sun’s glow and nowhere near our host constellation, but Uranus is up and well placed for viewing.

Holding just under naked eye visibility, this somewhat magnitude 5.8 fuzzy greenish blue dot is quite pleasant looking, even at its amazing 2.9 billion kilometer distance. Observers equipped with large telescopes and CCD camera can pick up a few of the magnitude 16.5 moons of Uranus. Isn’t technology wonderful?

Considered to be the last two Messier objects to be found during the annual Messier marathon, M72 and M73 are located in the bottom right area of the Water Bearer. The Messier Marathon occurs around the third week of March. If the moon is fairly close to new, telescope owners can catch all 110 Messiers in one night from dusk to dawn. Residing some 55,000 light years (ly) and past the galaxy’s centre, M72 glows at magnitude 9.3. M72 is however, not a very concentrated object. Move three lunar widths to the left and you will stumble over the four stars referred as M73. This grouping is a lot closer at only 2,500 ly away.

Head NNE from M72 by about three degrees until you come across the Saturn Nebula – NGC 7009. This unusually looking object sits only 2,400 ly years away and glows at 8th magnitude.  This planetary appears stellar in low power telescopes as opposed to larger instruments which helps bring out the vivid green colour. 

If you are game for a bright globular cluster (and who isn’t) move up to M2. This highly resolved object contains an estimated 100,000 members and shines at magnitude 6.5. This gem lies more than 50,000 ly away and is some 150 ly wide. Talk about tight quarters.

Still in the western side of Aquarius, be sure to stop by the galactic duo of NGC 6962 and smaller 6964. These two have registered magnitudes of 12.0 and 12.7 respectively with the primary being an estimated 180 million ly away. Marching on to the centre of Aquarius, we come across NGC 7302. The S04 elliptical galaxy has a bright core and naturally no arm structure. This splash of grey is estimated magnitude 12.1.

Before we leave the Water Bearer, stop by the Helix Nebula. Cataloged as NGC 7293, this planetary is the closest of its kind to us. Living on 450 ly away, its close proximity allows for excellent seeing. At magnitude 7.3, this planetary is about half the angular size of the moon.

One, if not the nicest object residing in Pisces is the bright face-on galaxy, M74. Glowing at magnitude 9.4 this spiral is an estimated 30 million ly from us. Amongst its 100 billion suns are pinkish nebula and clusters of young blue stars. The galaxy is roughly the same size as the Milky Way’s.

Another galaxy double appears as NGC 128 and 125. Separated by one fifth that of the Moon’s width, NGC 128 and 125 have magnitudes of 11.6 and 12.3 respectively. 

NGC 488 is a compact galaxy with a bright core and tightly wound spiral arms. Located some 35 arc minutes west of Alrisha at 90 million ly, it still shines at a decent 10.8 magnitude. Photographs will bring out its delicate arm structure. And finally within two thirds the moon’s width is the trio of NGC 467, 470 and 474. Fairly close in brightness to each other, their brightness are listed at 11.9, 11.9 and 11.1 respectively.

 

 

The Harvest moon will occur on the 7th at 23:13 eastern time and on the night of October 9 – 10, the Moon will glide over the Pleiades (M45). Depending where you live, our natural satellite will vary in the coverage of the cluster’s members. By 1:05 a.m. eastern on the 10th, the moon will be in mid occultation. With good weather, it should be a great show.

 This month we sadly say goodbye to Jupiter in the western sky. Although many transits are predicted, you might have a bit of a challenge fight with atmospheric turbulence. To replace this gem, we have the Lord of the rings climbing over the east at around 2:30 a.m. locally. And speaking of Saturn, congratulations to David H. Levy in discovering Comet Levy C/2006 T1 (Levy). David picked up this interstellar visitor on the morning of October 2nd, only .6 degrees (lunar width) from Saturn. At first he thought it was a ghost reflection of the planet itself.

Meteors, commonly referred to as shooting star can be viewed on any clear night. Earth however will be passing through the weak debris left by Halley’s Comet. The Orionid meteor shower is a modest display, peaking on the night of the 21st. On this night the maximum number seen by a single observer should be between 20 and 25 incoming bits of comet dust. But even at maximum, this shower has been known to drop of in numbers. You should still round up the family and head out under dark skies and witness Mother Nature’s fireworks in motion.

Twice a year namely in the spring and fall, when the ecliptic is at its steepest, Earth dwellers can catch the soft glow of the zodiacal light. At these special times, dust from our solar system reflects sun light and forms a huge faint cone of light measuring about 30 degrees above the eastern horizon. Many people have probably seen it but thought it was simple light pollution. Your two week window occurs after new moon (Oct 22nd).

Until next month, clear skies everyone.

Gary Boyle

garyboyle@sympatico.ca