In this issue:
* Dance of the planets
* How to buy a telescope
The Sky This Month
This section is optimized for southern Manitoba including the city of Winnipeg. All times are Central Standard Time (CST), the local time for Manitoba.
There are lots of events going on in the sky, but some are only observable with special equipment or are not of general interest. The events listed here are chosen so anyone can observe them. This is NOT an exhaustive list of what’s going on in the sky! You can also pick up Sky News magazine (www.skynews.ca) or consult The Observer’s Handbook 2008, available from the Royal Astronomical Society of Canada.
Dance of the Planets
Best seen: evening twilight all month (special events Dec. 1, 2, 28, 29, 30, 31)
There’s a celestial ballet going on in the western sky after sunset this month. The giant planet Jupiter has been visible all summer and is slowly sinking lower into the western sky. Meanwhile, brilliant Venus is rising out of the bright sky near the sun and becoming more prominent. The two are the brightest objects in the sky besides the sun and moon, becoming visible well before any of the other stars. You can watch them draw closer each night, as the combined motions of Jupiter, Venus, and our own Earth alter our perspective on the scene.
The highlight occured on December 1st, when the Moon, Jupiter, and Venus were all within a 4° circle in the southwest after sunset – and obscured by clouds for Manitobans. But there is still time to see the celestial ballet unfold.
In the first week of December, Venus moves higher and farther south while Jupiter sinks lower into the sunset. As the month progresses, Jupiter will be come very difficult to see, but you can catch it right after sunset if you have a clear southwest horizon – any trees, buildings or haze will block your view.
At the end of the month, the planet Mercury will appear below Jupiter for a brief showing. On December 28th, Mercury will be about half the height of Jupiter soon after sunset. The very thin crescent Moon will be below and to the right of the pair, but you’ll need very clear skies and probably binoculars to see them. On the next night (December 29th), the moon has risen above the two planets, and is much easier to spot. On December 30th, the Moon will be farther along its track, halfway between Jupiter-Mercury and brilliant Venus. The last night of the year has a crescent moon shining just above Venus, another great sight not to be missed.
For images of these events, visit Sky News magazine at www.skynews.ca.
How to buy a telescope
As the holidays approach, we often receive calls from people wishing to buy a telescope, for themselves or as a gift. There are so many choices that it can overwhelm the new skywatcher. Often, people just buy whatever telescope they find first that’s in their price range.
Sadly, these telescopes usually wind up being a disappointment, and are relegated to the closet after a few bad experiences under the stars. It’s not the fault of the observer - the telescopes carried in most department stores, camera stores and big box stores usually are usually heavy on appearance, but don’t actually do the job. Some beginner’s telescope sold today border on false advertising!
We recommend that you purchase any telescope from someone who knows and uses telescopes – a science or nature store, a science centre or planetarium, or a dedicated telescope store. Experienced staff who are also astronomers will be able to tell you what features you need and which telescopes are not going to perform. After all, you probably wouldn’t buy a car from someone who doesn’t even know how to drive!
The Planets for December 2008
Mercury becomes visible low in the southwest near Jupiter for the last week of the year.
Venus is visible in the evening sky this month as detailed in “Dance of the Planets” above.
Mars is too close to the Sun to be visible this month.
Jupiter is low in the southwest after sunset, and passes behind the sun early in 2009. It will reappear in the pre-dawn sky in late winter.
Saturn rises in the east about 1AM Standard time, and climbs halfway up the sky in the southeast by sunrise. The rings are still visible, but our perspective is becoming almost edge-on, and so Saturn is fainter than usual. This month provides our best chance to see Saturn’s rings as close to edge-on as possible – while the rings do get thinner later in the year, it occurs when Saturn is behind the sun and so invisible. Get your telescope out in the early AM for a look at Saturn’s thin rings!
Uranus is only visible to the unaided eye in very dark conditions. Binoculars and small telescopes show it as a pale green “star” with no details. Neptune is even fainter, and only visible with a telescope. The dwarf planets Pluto and Eris are unobservable without a telescope. For locator charts, consult the Observer’s Handbook of the Royal Astronomical Society of Canada.
Phases of the Moon:
Full Moon December 5, 2008 at 3:26 PM CST
Last Quarter December 12, 2008 at 10:37 AM CST
New Moon December 19, 2008 at 4:29 AM CST
First Quarter December 27, 2008 at 6:22 AM CST
Note: Phases of the Moon given here are in local time and date for Manitoba (Central Daylight Time); they may differ by what is on your calendar because calendars often use “Universal Time”, the time and date at the Greenwich meridian in England. Greenwich time is 6 hours ahead of Central Standard Time and 5 hours ahead of Central Daylight Time. Sometimes this pushes the date of an event to the previous day for Manitoba.