Tuesday, January 29, 2008

Build your own Planisphere (Star Finder)!

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One of the Astronomer badge requirements is to use a seasonal star chart. One of the most compact and useful star charts is called a Planisphere, Star Finder, or Star Wheel.

Tonight we will send home star finders with our Cubs. Our planisphere came from the National Research Council of Canada web site as a downloadable template you can make yourself, here. For best results print the template on stiff card stock.

The NRC also an online star chart and information on constellations and other astronomy, here. In fact, you could get most of what you need to earn your Astronomers badge from this site alone.

Using a planisphere is simplicity itself, you just dial the disk until the time of day lines up with the current date. Hold it above your head as you look to the sky (otherwise east and west are reversed).

You should adjust for Daylight Savings Time, by subtracting one hour when it is in effect. You don't need to adjust for leap years as the day to day change in the position of the stars is much less than an hour of the Earth's rotation.

Planispheres are actually designed for observers at specific distances from the equator (latitudes). A planisphere disk for Canada and the US, doesn't work well above the Arctic circle or close to the equator. Entirely different planisphere frames and disks are required in the southern hemisphere as the directions reverse.

Some other star finders templates:
  • The State of New Jersey publishes one, here. It's not too much different than the NRC one.
  • The Royal Astronomical Society of Canada has one, here. And other resources, here.
  • A southern hemisphere template can be found, here.
  • A northern and southern hemisphere templates can be found, here.
  • A Lakota star chart that may be usable in a planisphere frame can be found, here, with more information, here.
High quality planispheres can be purchased from local astronomy stores or online. One innovative design reduces edge distortion using a two sided approach, here.

ScoutBlogs - the search begins

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I've been on the lookout for interesting and useful Scouting Blogs (and web sites) and will be reporting on some of these in the near future.

There is a vast wealth of Scouting materials that can be found if one only looks. Scout related sites are reasonably well organized within the hierarchy of their country, region, and districts. Individual sites do a good job of cross-linking. And there are fascinating events, such as the Jamboree on the Internet (JOIT). Beyond this Scouters do not seem to have exploited other methods of linking and do not seem to be as well organized as some other groups on the Internet.

Other special interest groups organize in different ways, like:
  • Webrings - these use a ring host database to provide next/previous and random jumps through the ring. The problem is that rings alone don't work for really large numbers of sites. And one thing about Scouting is that there will be a large number of sites!
  • Blogging Networks - these aggregate like minded networks into a single feed. They're great ways for people to see the most current postings. But these too can become overwhelming. They are also designed as advertising channels. Like rings, this to fails to 'scale' up to the task of handling large numbers of sites.
As I add posts on this topic I will be cross-linking some of these sites from a new side section of the blog.

Update 1/31: I'd forgotten this post about using RSS/Atom feeds. Handy if you don't already know about them.

Sunday, January 27, 2008

Another asteroid "near" miss?

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A recently discovered asteroid, known as 2007 TU24, will pass "close" to Earth on January 29th, 2008 and a day before the predicted much nearer miss to Mars by another fast rock called 2007 WD5.

There is no need to get concerned (astronomers consider the Moon to be "close") and this will rock will be pass us almost half again as far away.

Astronomers may get a bit excited as it should be visible in modest sized telescopes (more than 6" apertures). It will pass west to east through the pointer stars of the Big Dipper. Sky and Telescope prepared a chart, here (the times are in UT 5 hours ahead of us). At magnitude 10.5, you would need to know more exactly where to look for it.

For more information see the NASA/JPL page on this rock, here.

And just so you don't get surprised, there are some alarming views being fired around the Internet based on a video claiming massive electrical disruption. It's complete bunk and a good astronomy site called BadAstrononmy.com has a video debunking these claims, here.

It is important to keep looking for these rocks because if we detect them early enough, we can do something about them. It's just important to understand that "near" misses are much more common than most people think.

Astronomers are conducting organized searches to find and track Near Earth Objects. A list of frequently asked questions can be found, here. The most recent results of these studies are published, here. Wikipedia maintains a list of notable asteroids, including record close passes, here, and there is an article on very near miss known as the Great Daylight Fireball of 1972, here.

Update 2008-2-8:
  • Tu24 missed Earth as predicted. There is an article on what we should learn from it, as well as what we can do about these, here.
  • WD5 is believed to have missed Mars and is now "lost" because its trajectory would have been altered by its close approach to Mars. See here. Also the Hubble was supposed to be taking pictures of it but I haven't heard of any being published yet. See here.
  • Another small fast rock called 2008 CT1 missed us on February 5th by 133,000 km (well inside the Moon's orbit). This is a 10m diameter rock that would have created a nice fireball like the one in 1972. See here.
TU24 and WD5 are asteroids, where as CT1 is a meteoroid. Essentially the difference depends on if the rock is larger or smaller than 50m in diameter.

A massive explosion over Siberia in 1908 and known as the Tunguska Event is believed to have been caused by a large meteoroid or small asteroid.

Update 2008-2-10: I found a good write up on 2008 CT1, here. It orbits the Sun every 307 days and crosses the orbits of Mercury, Venus, and Mars. It is expected to come very close to Earth again in 2041 and 2060.

The Toronto Fire Service visits the 433rd!

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At our last meeting, we had a visit from the Toronto Fire Service.

We learned about basic fire safety, including:
  • smoke alarms (batteries and hush buttons)
  • a family escape plan and meeting spots
  • calling 911 immediately
  • crawling out under the smoke
  • stop, drop, and roll
  • not reentering the building for any reason
  • not opening windows and blocking the crack under the door
  • making yourself obvious to firefighters (dancing in the window and not hiding in your room)
We also
  • learned about some of the leading causes of fires in Toronto.
  • saw a demonstration of firefighting clothing
  • had a fun obstacle course to test our fire skills

This activity counts towards our Family Safety Badge and Blue Star requirement B4.

Safety kits including an escape planning guide were sent home.

In the next couple of weeks Cubs can bring their completed plan in and we will complete the badge work.

Here are some links to fire safety resources:
  • Toronto fire prevention resources, here.
  • Sparky the Fire Dog, a kid and family focused site, here.
  • Kid focused activities for teachers from the Ontario Fire Marshall's Safety Council, here.
  • Parent resources from the the Ontario Fire Marshall's Safety Council, here.
  • Ontario Office of the Fire Marshall's main safety page, here.
Special thanks to Colin's mom and the TFS!

Tuesday, January 22, 2008

The Wolf Moon!

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Tuesday, January 22, 2008 at 8:35 a.m. EST is the full Wolf Moon! It may just be visible in the western sky when you wake and before school.

Native Americans named all the full moons and the months they occurred in. For a full list and more information see here and here. Some of these names, like Harvest and Hunter moons persist in popular use toady.
  • February 20th is the full Snow Moon and a total lunar eclipse (the safe to look at kind of eclipse). UPDATE: For more eclipse information, including times check this out.
  • November 13th, is the full Beaver Moon
Information on aboriginal star lore was largely word of mouth. Thankfully, people are now documenting it. There is a book on Inuit star lore and some websites dealing with Lakota star lore, including charts, here.

Knowledge of classical mythological or aboriginal star lore counts towards the Astronomers badge (requirement 3).

Sunday, January 20, 2008

EarthHour - Saturday March 29, 2008 @ 8pm

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Earth Hour is an interesting idea cooked up by the citizens of Sydney Australia and begun on March 31st, 2007. From the Toronto Star,
More than 2 million residents pulled the plug and the city went dark. Energy usage dropped by 10.2 per cent across the business district, more than double what organizers were aiming for, representing a reduction of 25 tonnes of carbon dioxide – the equivalent of taking 48,613 cars off the road for an hour.
Earth Hour is a great idea to show people the impact of climate change. It also shows people about the impact of light pollution. Light pollution is a major problem for astronomers but it also now being recognized as having other environmental effects. They've even got a word for it, scotobiology. The basic idea from a recent article, here, is that:
Plants and animals are programmed to function in a certain pattern of daylight and darkness. Alter it and unhealthy things happen. It applies equally to organisms that are active at night and those, including humans, whose bodies require regular periods with the lights out.
For more information, see the Earth Hour web page and World Wildlife Federation Earth Hour web page.

Unfortunately the organizers don't seem to have taken into consideration that most of North America will be on Daylight Savings Time during Earth Hour and people will not get the full effect of the night sky. Here's my hope that they schedule it an hour later (or two weeks earlier) in 2009.

I will have my telescope ready!

Twilight hours and a sunrise/sunset calculator

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A sunrise calculator for Canada can be found here.

This calculates Civil and Nautical twilight but not Astronomical twilight. For definitions, see here.

Astronomical twilight occurs after Nautical twilight by about the same amount of time as Nautical follows Civil. For example, twilight in Toronto for Earth Hour 2008 (Eastern Daylight Time) will be
  • Sunset - 7:41pm
  • Civil - 8:10pm
  • Nautical - 8:44pm
  • Astronomical - 9:20pm
A more complete (and complex) calculator can be found here.

Tuesday, January 15, 2008

The Tides Game

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The Tides Game is an educational steam-off game. The game illustrates the affect of the moon on the Earth's Oceans.

The players:
  • "moon" - a cub
  • "sun" - a cub/leader
  • "ocean" - the pack
Have the pack assemble in a parade circle. Explain that the part of the ocean closest the moon moves towards the moon slightly (one step outward) and that the ocean on the opposite side of the world will move in the opposite direction. After the moon passes, the ocean returns to its normal position.

Have the moon circle the Earth a few times.

Once they get the hang of the Moon, add the Sun. The Sun moves around the outside much slower. When the Moon and Sun line up, have the cubs take an extra step.

The game starts out slowly and gets faster.

For added fun and silliness, start with moon & sun moving normally and later add extra moons.

This should help your cubs understand the basics of tidal movement. Of course our tides are a bit more complicated that this, but it conveys the basics.

Astronomy Badge: requirement 5 (Know phases of the moon and moons role in causing tides).

Wednesday, January 9, 2008

Help Save the David Dunlap Observatory!

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The David Dunlop Observtory (DDO) in Richmond Hill is being sold off by the University of Toronto. The claim is that the DDO is no longer needed and that light pollution has destroyed it's usefulness. The DDO is the largest telescope in Canada and has been making useful observations outside of the visible light spectrum for years. The DDO site is also used by the RASC and other amateur astronomers.
The site is of historical and environmental interest and several groups are actively trying to block the sale of the site to developers.
The photos right were taken during the 433rd's last visited the DDO in 2004.

Here are some links to some of the groups:


Royal Astronomical Society of Canada - Toronto Chapter

The Royal Astronomical Society Toronto Centre, has spearheaded a working group, to save the DDO. See their website for details, updates and at further developments.

Save the DDO FaceBook Group-Join the Facebook Group!

Save the DDO!
Mathew Calamanici is a concerned Richmond Hill resident who is making a concerted Effort to save the observatory.

A group of naturalists who are concerned about the environmental impact of destroying the Carolinian Forest that surrounds the Observatory.
Helen Sawyer Hogg, a Professional astronomer at the DDO for many years, was a founding member of this group.

The organizers of the annual Mount Forest, Ontario, STARFEST astronomy convention are supporting the RASC effort.

Queens Park Rally. (Toronto)
Where: Queens Park Grounds, Toronto
When: January 16th 2008, 12 noon.
An organized rally is being held at Queens Park (University Avenue in Toronto) in a further effort to bring more attention to the efforts of many concerned citizens.
This rally has been organized by Tom Karmo , in conjunction with the Richmond Hill Naturalists and other concerned citizens.

Thanks to Ray Khan for these links.

Astronomy and space in the news

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Here are a few links to some interesting astronomy articles from (mostly) last year.
  • Will an asteroid whack Mars, here?
  • The importance of searching for small asteroids, here.
  • The weird case of the Death Star Galaxy, here.
  • A "nearby" star with 5 planets, here.
  • Why a space probe was confused with a possible dangerous asteroid, here.
  • Uncle Sam is going to Mars, here.
  • Why the Moon makes us special, here.
  • The case of the comet's disappearing tail, here.
  • The little robots that could, here.
  • Roving satellite photographs the dark side of Earth, here.
  • More clues to life on Mars here.
  • Large Earth like planet discovered orbiting a Red Dwarf star, here.
  • Worlds in collision, here?