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The Sky This Month - December 2006

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Written by Gary Boyle, Ottawa on
Post Date: 
Mon, 2006/12/04

Some Pretty Cool Galaxies

Public star parties are a great place to show the wonders of the night sky to children and adults alike. One of the most frequently asked questions asked is, you guessed it, “how far can you see with this telescope”? In response the term light year is defined as a rounded off figure of ten trillion kilometres. Turning our instruments skywards to a faint smudge, we rattle off the estimated distance (in light years) we have previously read in books or found on web sites. With distances of nebulae and star clusters are listed in the thousands of light years category while residing in our Milky Way Galaxy, however, remote galaxies would be the correct answer.

The average telescope sold on the market today can glimpse these distant objects lying tens of millions of light years from us. However, in saying that, the lunar phase, sky conditions and the object’s faintness are important factors to be taken into consideration. With lengthy frosty December nights, we have a wealth of remote targets to choose from.

Starting from Rigel, Orion’s right foot, we find Eridanus – the River. This original constellation drawn up by Ptolemy, snakes far below our southern horizon. To start our watery patrol, turn your scope to NGC 1300. This classic version of a barred spiral galaxy is estimated to be 150,000 light years wide and some 75 million light years from us. Its brightness is pegged at magnitude 10.5. Within one and a half lunar widths above NGC 1300 you will first come across NGC 1297, a magnitude 13 round galaxy with a fairly bright center. They form a pretty pair around 50X. Continue further north by about a full moon’s width is NGC 1301, an elongated 13th magnitude smudge. Depending on aperture size of your scope, this might be tricky.

Slide about two and a half degrees to the south east of NGC1300 till you spot the very elongated galaxy, NGC 1332. Rated a touch brighter than NGC 1300, it does possess a bright nucleus. Parked next to NGC 1332 along its axis is the faint galaxy NGC 1331 which is also catalogued as IC 324. Completing the galactic triangle is NGC 1232. To find this magnitude 9.9 face-on spiral galaxy move about two and a half degrees to the south west of NGC1300.

Situated about half way towards the star Rigel is a nice planetary with a central star. This 10th magnitude objected is called NGC 1535 and at an estimated distance of a mere 1,500 light years, takes on a similar appearance as does the Eskimo Nebula (NGC 2392) in the constellation of Gemini.

Moving along the one o’clock position in northern Eridanus lays a nice chain of six remote galaxies. This broken line of faint fuzzies, stretch from NGC 1453 down to NGC 1358 and includes IC 347. They range in brightness from 12th to 13th with the brightest of the group being NGC 1453 glowing at 11.4. I have provided a close up view of dozens of galaxies down to 13th magnitude. This chart is courtesy The Sky by Software Bisque.

Object

Type

Magnitude

RA

DEC

NGC 1300 Galaxy 10.4 3h 20m -19d 23m
NGC 1297 Galaxy 13.0 3h 20m -19d 04m
NGC 1301 Galaxy 13.0 3h 21m -18d 43m
NGC 1332 Galaxy 10.3 3h 27m -21d 18m
NGC1232 Galaxy 9.9 3h 10m -20d 33m
NGC 1535 Planetary Neb. 10.0 4h 14m -12d 43m
NGC 1453 Galaxy 11.6 3h 47m -3d 56m
NGC 1358 Galaxy 12.1 3h 34m -5d 04m

Of course before we pack away our scopes, you must stop by and pay a visit to the Orion nebula. A true showpiece in any sky, this stellar nursery rests at 1,500 light years away and shows an incredible amount of detail. Large aperture scopes begin to reveal a hint of green. I never grow tired gazing upon it with the unaided eye, 7 X 35 binoculars or my 12 SCT telescope. Every view is almost a first. The ringed marvel Saturn is now well above the eastern horizon by 11 p.m. locally. It is just under five degrees west of bright star Regulus in Leo and forms a nice trio with the moon on December 9th. Moderate telescope will reveal up to five Saturnian moons.

Venus is slowly pulling away from the Sun’s glare in the west. Over the weeks you should pick it up just after sunset. Mercury, the sun’s closest sibling is still putting on a great show in the eastern skies before Sunrise. This tiny world will appear within a one degree circle with Mars and Jupiter in the early morning of December 10. The Space Shuttle Discovery is scheduled to lift off on mission STS-116 to continue work on the International Space Station. The station is supposed to be complete in 2010 before the shuttle fleet is retired.

You can follow the entire mission from liftoff at 9:35 p.m. eastern on Dec 7th, to the scheduled landing on Dec 19th at 4:35 p.m. eastern, on your computer via NASA TV. Observation wise, step outside and glimpse the shuttle along with the space station as it orbits the earth once every 90 minutes. Enter your city, choose ISS from the Satellites section and keep checking for updates of timings. Click on a particular date will prompted a finder chart showing its predicted path.



The Geminid meteor shower will peak on the morning of December 14th. This major shower is quite spectacular to witness as the debris from asteroid 3200 Phaethon enters our atmosphere at a much slower speed than other showers thus producing graceful views and long, sometimes colourful trails. Tiny sand size or larger particles strike the atmosphere at about 100 km high and plummet at a mere 36 km/sec mostly appearing white in colour but can also show up as yellow, red and blue. With the moon being close to a waning crescent, it will not interfere with the sky show which is estimated to produce more than 100 meteors per hour per single observer. This is an event for the entire family, so bundle up warm and head out of town.

Finally, winter solstice officially announces itself in the northern hemisphere on December 21st at 7:55 p.m. eastern time. For people living in the Southern Hemisphere will celebrate their Summer Solstice. The word “solstice” means stand still. Now the days and night will be getting a touch longer as the weeks march on.

This month the full moon also called the “cold” moon occurs on December 4th so you observing window will open around the 9th of the month.

Until next month, clear skies everyone.

Gary Boyle
garyboyle@sympatico.ca