Laser pointers, bans, and stupidity

New South Wales just passed a law banning the use of high power laser pointers without a permit. See here. However, the effectiveness of law is already being questioned. See here and here. NSW is not the first place to put in place such a ban.

The ban was prompted by some recent misuse of laser pointers, where beams were flashed at the cockpits of aircraft that were taking off and landing. Let's make no mistake. There is simply no excuse for intentionally targeting aircraft (or any vehicle) with a laser. To do so is 1st degree stupidity at best.

Update: It turns out that the idiots pointing lasers at aircraft aren't the only stupidity in this story.

• In an ironic twist a local Sydney (NSW) art object has been reported to reflect green lasers into the sky and has reportedly hit a helicopter pilot in the eye. See "Sydney skies menaced by deadly raygun disco-ball".
  
• Premier (NSW) Morris Iemma opined that a pet toy would be a valid reason to own a laser, see "Laser ban impossible to enforce".

The real question is will the ban be effective? And by this I mean, are we going to see a meaningful reduction in the kinds of incidents that provoked this ban? Politicians seem to love to ban things. More often than not these kinds of bans are ineffective theatre designed to let them say they are taking action.

Such incidents are also not unique to Australia, they have been recorded in the US and Canada and there are incidents dating back to around 2003. See here and here.

Understandably the pilots union supports a ban on these devices. Thankfully they were open to legitimate uses such as astronomy.

Laser pointers can be invaluable for teaching astronomy to small groups of people. They can also be annoying to other astronomers if used carelessly. Like many issues, finding a balance can be challenging.

Incidents such as these are a natural consequence of technology, any technology, becoming inexpensive and widespread. I have a hard time believing that these could be accidents. How many of these incidents were fuelled by anger, alcohol, or drugs? How many were poorly thought out pranks?

Banning high powered laser pointers and requiring a permit will raise the bar for people getting these devices. Essentially there are three groups of people to consider. Those with a legitimate need that will go through the bureaucratic hoops to continue using one. Those that do not will circumvent the system with intent. And those in the middle that don't have a legitimate need or the determination to get a permit. A ban is really only going to affect the middle group.

Handheld lasers exceeding 500 mW are for sale! Also, there are widely videos showing you how to build your own high power laser using surplus CD and DVD lasers (specifications vary from 30 mW to 300 mW with 100-150 mW being common)!

The problem is not the inexpensive laser pointers available in dollar stars. They aren't very powerful, typically under 1 mW, and can be used for presentations and entertaining pets. While I doubt these would have any effect on pilots at range, I would err on the side of caution and not want to test the assumption.

Laser pointers used for astronomy are something else all together. For starters the human eye responds poorly to red and blue light compared to green. A green laser should give you the best visibility with the least power. But how much power?

A number of factors affect visibility. The thickness of the beam. The moisture in the air. Even light pollution.

Over the years I've borrowed a few of these devices to use as star pointers. The smallest was a 5 mW green laser. This just didn't cut it. It was only really barely visible on moist nights with dark skies. On the other end of the spectrum, was a 55 mW class IIIb green laser. This one seems to be visible in just about all nighttime conditions. While this is a far cry from the 500 mW ones I've seen advertised, it is still over powered for star pointing. I've had discussions with others that suggest a 15 mW laser should be adequate for star pointing. But what I'd really like to see is something with variable power so that you can get just what is needed and no more.

Safety with these lasers is a matter of awareness, attitude and responsibility. When I was a Scout, I learned to shoot a rifle. We were taught never to point a gun at anything we did not intend to shoot. Never under any circumstance. The same applies to a laser pointer. When I use one, I follow a few simple rules:

• Keep control of the laser at all times yourself. Avoid rapid and wide movement. Don't let children use the laser.
• Never point the laser at anything that might be an aircraft (or vehicle). Avoid moving objects and flashing lights.
  
• If you need to point at a moving object, trail behind it. Do this even if you're sure it's not an aircraft. During Earth Hour, I was pointing out the International Space Station. Even though I was 99.99% sure it was the ISS and the laser couldn't affect the people on it, I still trailed the laser behind it.
• Be aware, look around carefully before pointing.
• Be respectful of other groups around you.
  

A NSW man was recently sentenced to three years in prison for shining a laser pointer at a police helicopter. See here. Others have been similarly convicted in other jurisdictions.

Now what will bans like these actually do?

• It will probably raise awareness of the risks.
• It may make it harder to obtain and use powerful laser pointers. Although without importation bans this will be less effective.
  
• Fewer people will seek to own such devices. (probably)
• Conversely by banning them, more people may want to own these devices.
  
• It may promote more responsible behaviour from laser owners. More likely it will slow the growth of irresponsible owners.
  
• And adds to the possibility of stiff penalties for abuse. Although, other laws can be used for this purpose and stiff penalties have already been handed out.
• It may not even help police track down abusers, because you can't simply stop looking after you've checked out all the permit holders. The abuser probably won't have a permit.
  
• It may criminalize people unfairly if not carefully applied (probably).

Will bans like this reduce such irresponsible incidents? That remains to be seen; but, I suspect that it will be less effective than its' authors hope. It also raises a lot of questions about what is considered "legitimate use" and who will be legitimate users. Lastly, I'm concerned about overzealous enforcement.

April - Last chance to see DDO Canada's largest telescope

I just received confirmation that the David Dunlap Observatory is shutting down tour operations. I expect this is the first step in the shutdown relating to the sale of the property.

There is a brief window of opportunity for any groups remaining to see it and I wanted to get the word out.

Any Scouting (and Guiding) groups from wishing to see the largest telescope in Canada have one last chance to visit. The staff can accommodate all age ranges from Beavers through to Rovers. But you must act fast to secure a spot.

The following dates are available April 21, 23, 25, 27,28, and 29th. No tours will be run after April 30th.

Group size is not important at this point. It can be 10 people to 70 people and can include family and friends. The fee is $5 per person. The minimum deposit is being waived.

If you know of groups that could be interested, please pass the word.

♫

To arrange a tour contact the DDO by email tours@astro.utoronto.ca or see http://www.astro.utoronto.ca/DDO/public/tourschedule_scouts.html

The 433rd Cubs recently visited the DDO and had a great time.

Thanks, Mang

Navigation without a compass (or GPS)

Every good Scout should be able to find their direction. Even without a compass! Or a GPS unit. But how?

How many ways are there to find north and south. It turns out there are a lot. Most methods that take advantage of basic astronomy that allow you to find true north and south. These are methods that could come handy in a survival situation.

The picture above illustrates one of my favorites. It isn't taught as much because watches have gone digital and the method is seen by some as anachronistic because of this. The picture pokes a bit of fun at this because I borrowed a cellphone that had a "retro" watch face. The setup shown is northern hemisphere during standard time (it wasn't but it's just an example). The yellow line shows north.

If you've become lost the simplest recommended method is the Hug a tree approach. This prevents you from getting further lost and facilitates rescue. Navigation methods like the ones described here are a bit more advanced. Nonetheless they are worth practicing! They won't easily help you find a small site like a camp, but wide things like highways and major rivers are another matter.

Watch Method

This method is fast, portable, and reasonably accurate for these kinds of general methods. And even if you don't have an analog clock face, then you can draw one easily enough. It's not perfect (see below), but handy.

Cast a shadow across the watch face.

• In the northern hemisphere, align the hour hand to the shadow. You will now need to bisect an angle (find the halfway angle) between the hour hand and noon (or 1pm if you are on daylight savings time). The line running through the bisected angle will run true north-south. North will be the side of the line closest to 3 o'clock in the morning and 9 o'clock in the afternoon.
• In the southern hemisphere the approach is almost identical (it would be if you had a clock that runs anti-clockwise). In the southern hemisphere align noon (or 1pm if you are on daylight savings time) to the shadow. Bisect the angle to find the north-south line. North will be the side of the line before 12 in the morning and after 12 in the afternoon.
  

If you're lucky enough to have a 24 hour analog watch face, you don't need to bisect the angles.

Some drawbacks include that you can easily be off the width of a timezone which is typically an hour but can vary. Knowing if you are close to a timezone boundary will help with this. It's also not supposed to very good if you are either too close (under 20°) or too far (more than 70°) from the equator.

Sun Methods

There are several methods for using the Sun to find direction.

1. Knowing that the Sun rises in the east and sets in the west. You can figure an east west line at sunrise or sunset. There will be some variation depending on the time of the year and length of day, but the Sun should be due east/west at 6 o'clock am/pm.
2. "Shadow Tip" methods. These are described in detail in an article below. Basically, there are different ways to get an east-west line. The one that makes the most sense involves taking measurements on equal times before and after mid-day. While I haven't tried the others, I have a hard time believing that drawing a line between two shadow tips at 20 minute intervals around 7am will result in an east-west line. (But perhaps I missed something.)
   

Star Methods

Locating direction using stars can be accomplished by several methods.

1. Use sticks to track the rise and set of different obvious stars. This is a method that was believed to be used by the ancient Egyptians to layout the pyramids. The line between the rise and set of a bright star should be an east-west line. Of course, this requires you stay put for a while.
2. Locate a landmark beneath the pole,
• In the northern hemisphere, this is beneath the north star located by using the pointers in the big dipper. See the Astronomers badge.
• In the southern hemisphere there is no easily visible pole star so it's trickier. You need to find the long axis of the Southern Cross (Crux), the pointers in Centauri, and Achernar in Eriandus. These intersect over the south pole. Some of the diagrams on the web don't show the pointers and this intersection. For more detail see here. Also, be wary as there are false pointers, a false cross, and the diamond cross to confuse you. For more see here. (As I've never been this far south, I'd love to hear from someone who's actually done this. Musca where are you?)
  

Moon Methods

1. This is another approximate method. Basically, the phase of the Moon will tell you the location of the Sun. Additionally, if the Moon rises before the Sun sets it is trailing the Sun and the bright side will point approximately west. If the Moon rises after midnight it is leading the Sun and the bright side will point approximately east.
2. Another interesting looking trick is described as a "finger of shadows" on a nearly full Moon to point due north. It can be found here. I may be wrong but, this sounds overly wordy and colourful.
   
3. The previous trick got me thinking about a crescent Moon. The line between the tips of the crescent should run approximately north-south. This makes sense if you consider that the Moon orbits close to the ecliptic (within about 5°) and will be illuminated from north to south.
   

Mobile Software

Non-GPS software is available for a number of mobile phones and PDA's. I'm most familiar with Palm OS based tools, but I understand there are versions for other devices such as Windows mobile. Possibly the Blackberry and other devices? I'd love to see comments on recommendations.

• Sun Compass for Palm
• Sol! a Sun compass for the Palm
  
• A number of Pocket PC and Palm "Sun compass" products can be found at PocketGear.com.

Some odd time pieces, compasses, and related items

• I wasn't kidding about backwards or reversed clocks. They are commonly available for left-handers or as novelties. One example see here. (It would be exceptional to see one with a 24 hour dial.)
  
• Surveyors used very accurate Solar compasses because magnetic compasses could often be thrown off by deposits of magnetic minerals. A photo of one can be found here.
• I recently saw design for an unusual clock called the "Bulb Dial" clock, here. It's sort of a minimalist and Rowland_Emett-ish at the same time. (Emett is known for his wacky art-inventions that were featured in the movie Chitty Chitty Bang Bang and regularly displayed at the Ontario Science Centre in "The Magical Machines of Rowland Emett").

Sort of related DIY projects

• While I 'm not certain you can find north-south with it, a related find was instructions for a do it yourself Sextant using a CD case and Lego, here. (Careful about the sun filter).
• Earth dials are interesting and would make an interesting school or Scouting project. This Planetary Society article provides instructions on how to build one.

Other methods and links

• For more information on these methods see this Wiki How To article. This covers many of the methods mentioned in more detail including using a digital SLR camera and a cell phone as well as the watch method, shadow stick, and star methods.
  
• Another explanation of the clock method with diagrams can be found here.
• Yet another explanation of several methods can be found here.
• The Planetary Society posted an article on Earth Dials (see below) with links that include a sites that calculates magnetic deviation for your locale and several links for teachers and kids including Astronomy with a Stick.
  

Browser wars part deux!

Most people take browsers for granted and think of the browser wars as ancient history. Well they're back.

Some of this diversity is a good thing. But the problems of security and compatibility lurk beneath the surface.

Browser diversity

There are a surprising number of browsers out there and even a small site will get a fair spread of visitors. Judging from the visitors to this site (and discounting my own activity), we have:

• Internet Explorer or IE (50%) with 3 versions
  
• Firefox (36%) with 6 versions
  
• Safari (7%) with 1 version
  
• Opera (1.3%) with 5 versions
• Others (5%) including Konqueror, Camino, Netscape, Mozilla (pre firefox), and the ever popular blank or noname.

I have yet to see a visit by a Flock user.

Recently Apple has been trying to make a big splash with Safari. They got themselves into a bit of hot water by being aggressive and misleading using the iTunes updater to install Safari on Windows, here. And looked a bit silly because the click through license disallowed installs on Windows, here.

Security

Older browsers are vulnerable to all kinds of security problems and are actually unsafe on many pages.

Unpatched security vulnerabilities make it possible for criminals to easily infect computers by planting malicious code on web sites and waiting users to visit. It's been called "drive by downloading". It's not just reserved for fake websites and spam blogs, many legitimate web sites have been laced with nasty malware.

Security studies in 2005 and 2006 comparing IE with Firefox found that IE (v6) was unsafe 98% of the time! In fact, about 30% of our visitors are running unpatched browsers.

• About 20% of the visitors to this site are running the insecure IE v6!
• Also about 2.5% of visitors to this site are running insecure versions of Firefox.
  

Of course, not all vulnerabilities are equal and if you want to do some research, vulnerability information can be found at Secunia.com as well as numerous other websites. Click on one of these links for a vulnerability summary for IE7, IE6, IE5.5, IE 5.0, Firefox 2, Firefox 1, Netscape 7, Camino, Opera 9, Opera 8, Safari 1, and Flock 1.

Firefox can be supplemented by a variety of Add-ons which can improve both functionality and security. A few of my favorites are NoScript and Adblock Plus.

Compatibility

Older browsers are also functionally problematic. It goes beyond not supporting newer web functionality, some of them don't follow standards and require web developers to go through all kinds of quirky hoops to get even simple web pages to display properly in all browsers. IE6 and earlier were notorious for being non-standard. Developers even have a name for one of the problems, it's called Quirks Mode. It's been argued that Microsoft likes this because it promotes their lock-in. Developers by and large hate it because it destroys interoperability and promotes lock-in.

By way of example, when our web developer put together the "Forest Friends" page for the 433rd website the animals originally lined up properly only in IE. The site looked nasty in every other browser. Some experimentation and adjustment was required to get it working for standards based browsers like Firefox and Opera. If you look in the page source, you will see comments describing the gory details of how the page was adjusted.

End6!

One web developer has been so miffed by these problems, he started a campaign called End6! to get rid of IE6 (and earlier) non-conforming browsers. This was picked up by another group, here, and caused some controversy, here. Just to be clear, he's not trying to get rid of IE. Just old non-conforming IE.

Take the End6! test, here. Of course it requires JavaScript to be enabled.

Making MOST

As part of our Space Exploration Badge we built a full scale model of a satellite! Here are some pictures of our model.

Canada and Canadians have a history of innovation and success in space exploration. From Alouette 1 to the Canadarm and Canadarm2 used aboard the Space Shuttle and International Space Station. By 2006, Canada had over 33 payloads in orbit. One of these is a tiny observatory called Microvariability & Oscillations of STars (MOST) that is making a big splash in the field of astronomy.

Most is a micro-satellite, about the size of a large suitcase, that was launched by Canada on an Russian rocket in 2003. Launched on a modest (for space exploration) budget, MOST has been called the Humble Space Telescope in reference to its much larger and more expensive predecessor the Hubble.

MOST orbits the earth from pole to pole in perpetual darkness and can keep its cameras focused on stars for almost two months! Because it can pick up small variations in light from the stars it observes, MOST can be used to study planets orbiting other stars and variations in the star's atmosphere (a bit like studying earthquakes). MOST hopes to answer questions about how the Sun may evolve and even how stars contributed to the formation of solar systems.

Expected to operate for about one year, it's still going. In fact, the science team has opened up to the public to propose observing targets through the My Own Space Telescope project!

MOST is unusual for a space telescope in that it uses an unusual lens design. The Fabry microlens array spreads light from target stars over a large number of pixels to achieve high resolutions.

The 433rd has contributed too. Mitchell's dad is part of the operations team, Mang has proposed a couple of targets. Here's a chart showing the parts of the sky MOST can see and some of the official candidate and selected targets.

The chart shows the sky mapped out against the coordinates used by astronomers. The x-axis is the Right Ascension (in hours) and the y-axis is the Declination (in degrees).

There are three zones that are important to MOST. The CVZ (Continuous Viewing Zone) is where MOST can keep itself focused for up to about 60 days at a time! There are two SS (Sun Sensor) zones. Targets within the SS zones represent the extreme range of the telescope and can be focused on for shorter time periods. If you are really interested in a star in the SS zones, one trick is to pick a second star and switch between the two. These are called "switch targets".

These targets are all taken from the official web site for MOST. One thing that may be of interest is that some of the candidate stars were chosen before the operational parameters of MOST were well understood. If you look, you will see candidates well outside the SS zones.

This particular chart shows two stars that I proposed for observation. One is a switch target. Can you figure out what they are? And why I picked them?

Another surprise for me was that I could actually get Excel to produce a chart like this!

More information on MOST can be found at

• Wikipedia
• The Canadian Space Agency, and Most @ the CSA.
  

Do you recognize this badge?

Last meeting I was looking at our Pack's inventory of badges to see what we were short (and long) on. And I came across this one in our stock.

Now I started in Scouting as a Cub in 1967 and a lot of the badges are familiar. Others are obviously newer. But this one I didn't recognize right out, even though it seemed familiar.

It turns out it's discontinued.

Do you know what it is? Can you guess?

The background may provide a hint.

Calculating Easter

Most people know that Easter moves around a bit. They look it up on the Calendar and leave it at that. But why?

The Short Answer

If you just want a list of Easter's for this century, The Astronomical Society of South Australia has a list here. But you still won't know why.

The Story

It turns out there is quite a story behind this movable holiday. The calculation of Easter has had broad reaching effects that most people are blissfully unaware of.

Good Friday and Easter, are the days Christians recognize the Crucifixion of Jesus Christ and the Resurrection. The Bible tells us that this was a Friday because the Sabbath began that evening. It also tells us that was during Passover because Pilate offers to release Jesus as is the custom during Passover. Easter, also called Pascha, follows on the Sunday. Easter Monday is a remnant of week long celebration and is not just a "bank holiday". There is also some debate if the Last Supper was a Passover meal or not.

At this point you might be tempted to think that Good Friday should be the first Friday in Passover or that it should be on the same day each year. If only it had been that easy.

Now since Passover is based on the Hebrew calendar which is Lunisolar (a hybrid of Lunar and Solar events) the Moon is involved. This is why it moves around on a solar calendar. Anytime you have overlapping calendar systems be prepared for some complication.

Complications did ensue. Some people thought it should be on the same date in the year and others thought Easter should be on a Sunday. This led to disagreements, including the excommunication of the Quartodecimans. And while it seems that folks later made up, this may have been one of several precursors to later disagreements that split the the church.

Easter is defined as the first Sunday after the first fourteenth day of the the Paschal Full Moon that is on or after March 21 and the vernal equinox. However, just to complicate things this full moon doesn't always correspond to a real full moon. Although it should be within a day or two.

The multiple references to 14 (quartodecima) arise from the original dating of Easter after the 14th day of Nisan on the Hebrew calendar. Nisan falls in the March-April time frame.

So Easter can fall anytime from March 22nd to April 25th on Christian calendars. And yes, I meant calendars plural. While the west uses the Gregorian calendar, Eastern churches mostly use the Julian calendar. The result is that Eastern churches celebrate Easter from April 4 to May 8 on the Gregorian calendar. Despite this, Easter sometimes falls on the same day as in 2001, 2004, 2007, 2010, and 2011.

The main differences between the two calendars is in the way they handle leap years and leap days. The Julian calendar has too many and consequently that calendar gets ahead of the seasons. Pope Gregory XIII advised by Clavius and Kepler reformed the calendar to bring the Equinox and Easter back in line with the start of spring.

Now before I wander off topic with these last notes, please consider that I am not one to get hung up on literal interpretations of the Bible. As Jesus said, give to Caesar what is his and to God what is God's. I choose to rely on science and faith for the things they each do best. And, I think, mixing them up is unwise.

Of Other Things Easter Related

The Biblical account of the Crucifixion speaks of three hours of darkness, earthquakes, and the Moon turning blood red. Some people believe that the darkness is an eclipse and have used that to try and get an accurate date for this event. However, the facts don't support this. Daytime (Solar) eclipses last only minutes and they happen on the new moon. Lunar eclipses happen on full moons and turn the moon red but they happen at night.

Another problem is that the year and date of Christ's birth aren't really known exactly and may vary from 8 BC to 6 AD. Some people have tried to fit astronomical events to the birth of Christ, but there is simply too much uncertainty. The determination of AD or Anno Domini (the year of our lord and not "after death") was calculated by a monk named Dionysius Exiguus. Prior dates became Before Christ. Ironically, Dionysius didn't set out to determine when Christ was born but was calculating tables of Easter dates.

BC/AD have become widely accepted outside of Christian culture but they are often referred to as BCE and CE (Common Era).

Dates BC/AD cause mathematical problems. Consider, is there a year zero? Since the Romans had no number for zero, the Early Christians wouldn't have had one either. Mind you Dionysius almost coined it! One of the few sciences that actually has to accurately deal with spanning BC/AD is Astronomy. And for ease of calculation, astronomers have their own years which use integer notation. We are living in +2008, 1 BC is 0, and 2 BC is -1.

There is an old myth that you can make an egg stand on end at the moment of the Vernal Equinox. You can. But you can also do it other times as well. A couple of articles and a video were published, here and here.

Exactly how did we get from the Biblical events of Easter to Rabbits and Eggs? Wikipedia has some ideas, here.

And while I remember, folks from Purdy's Chocolates were handing out free samples at the Ontario Science Center during March break. Yum!

Update:

• Astroprof posted a discussion of the Easter Moon and the difficulties of calculating Easter.
• Additional links about Easter and astronomy can be found over at Cosmos4u at the bottom of the article.
• The Toronto Star published an account of why Easter is so early. Nice photo of the Cathedral of Strasbourg's astronomical clock too. See here.
  

David Dunlap Observatory Tour and Photos

On March 4th 2008, the 433rd Cubs, parents, and a few Scouts paid a visit to the David Dunlap Observatory. Unfortunately the weather did not cooperate and we couldn't actually see the stars or do our work for the Globe at Night's light pollution awareness project. We were fortunate to beat a major snowstorm that descended on the city shortly after we left.

We were able to take in a presentation at the administration building that covered many of the requirements of the Astronomers Badge. The tour also counts towards requirement B3 or the Black Star. Our cubs had some good questions and demonstrated their knowledge of astronomy including one or two things that surprised me.

Afterward we were able to visit the observatory dome and see the telescope. The scope is quite massive and the Cubs were impressed that it was so finely balanced that impatient astronomers could move the 25 ton assembly by hand!

We learned a bit of the history of the facility, its use for astrophotography, and a renown Canadian astronomer Helen Sawyer Hogg who conducted research at the DDO for many decades.

We also saw a spectrographic lens and learned a bit about some of the work being done, including a study of rather bizarre systems known as contact binaries. In these systems two rapidly co-orbiting stars are so close they actually touch but do not merge! There are a number of interesting question that aren't known about these including how they came so close.

Hopefully, we will be able to return later this spring to actually look through the eyepiece!

Our thanks to Tuba Koktay, Ian Shelton, and Thomas Karmo at the DDO.

Article on Binocular Astronomy

A while back I wrote that your first telescope should be a good pair of binoculars. This morning I came across an article on things to look at with those binoculars using Sirius as a reference star. You can find the article at Universe Today. From Sirius you should be able to find two or three Messier Objects even in the city.

Cubs working on their astronomy badge should recall that Sirius is easy to find. It's the very bright star, trailing Orion slightly to the south and east. From Etobicoke we can see down to magnitude 4 on a good night.

And if you want to look at more, there's always the wonders in Orion!

Astronomical distances are .... (well) astronomical

How can someone begin to describe astronomical distances?

We sometimes use fancy compound terms like outer space, deep space, interstellar space, and intergalactic space.

Image used with permission of Jim Boles.

You can be factual like NASA's page on cosmic distances or Wikipedia's page on astronomical distances.

You can use humour to make your point, like Douglas Adams in the The Hitchhikers Guide to the Galaxy:

Space is big. Really big. You just won't believe how vastly hugely mind-bogglingly big it is.

You can even be darkly poetic, like Michael Moorecock's "Dark Corridor" introduction to Hawkwind's "Space is Deep":

Space is infinite, it is dark
Space is neutral, it is cold
Stars occupy minute areas of space
They are clustered a few billion here
And a few billion there
As if seeking consolation in numbers

But none of these help you visualize how big space is!

Think of the Earth as a shiny blue marble (standard marbles are 1.25 cm or 1/2" in diameter - smaller than the one in the photo). Below are some approximate comparable scale sizes for objects /distances in our solar system:

• The Moon - 3.5mm or 0.13"
  
• Mercury - 5mm or 0.2"
• Mars - 7mm or 0.37" - a chickpea
  
• Venus - another marble (a bit smaller than Earth)
• Low Earth Orbit Satellites - basically the same size as the marble
• Uranus -5 cm or 2" - an orange
  
• Neptune - another orange (a bit smaller than Uranus)
• Communications satellites (geosynchronous) - 8.25 cm or 3.25" - a hockey puck
• Saturn - 12 cm or 4.75" - grapefruit
• Jupiter - 14 cm or 5.5" - a slightly bigger grapefruit
  
• Saturn's visible rings - 26.8 cm or 10.5" - an old LP record
• The Sun - 1.36 m or 54" - a small weather balloon or large exercise ball

Okay, that was fairly easy. So you might be considering a scale model of the solar system using fruit, vegetables and some odds and ends from a garage sale. Now you need some real estate.

Wait for it! Still using our marble for Earth, the Moon would be 0.75 m or 29" away. Or about an adults' arms length. Below are the approximate distances of things from the Sun using the same scale (I'll give up on Imperial measures here):

• Mercury - 136 m - a bit larger than a football field
• Venus - 213 m
  
• Earth - 293 m - a bit shorter than the Eiffel Tower
  
• Mars - 488 m - a bit shorter than the CN Tower
  
• Jupiter - 1.6 km
• Saturn - 3 km
• Uranus - 6 km
• Neptune - 9 km
• Pluto - 14 km at its' farthest
  

That is a very long hike from our little blue marble!

Now if you wanted to place these to scale and allow space for the full orbits of all the planets and Pluto (it was demoted to a dwarf planet), the Sun would need to be in Mel Lastman Square in North York at the center of a 28km circle running from Lake Ontario to north of the David Dunlap Observatory in Richmond Hill!

If you're wondering what that looks like, take a look at this map of the Solar System in Toronto.

And it gets worse:

• Proxima Centauri the nearest star at around 4.2 light years would be 77,000 km away from our marble. On scale, the marble is about 1/5 of the way to the moon!
• Betelgeuse a red supergiant about 430 light years away would be 7,883,333 km away. On our scale, that's about 1/8 of the way to Mars at it's closest or about 1/20th the distance to our Sun.
  
• The Milky way galaxy is about 100,000 light years across. So our marble is now about 1.8 billion km away or outside the orbit of Saturn.
  

Galaxies are millions of light years apart, the Local Group of galaxies containing our own Milky Way is about 10 million light years across. On the scale of our marble, the local group only gets us about 1/200th the way to the nearest star! The Universe itself is billions of light years across.

I'll stop now before my head hurts trying to visualize all of this in terms of our little blue marble.

Astronomical distances operate on levels. Just when you think you've gotten used to one of them, you'll see another and be humbled all over again.

Polite Comments are Welcome, SPAM is not.

I encourage comments on this blog. I just ask that if you make them consider that the audience is includes kids. In particular kids of Cub and Scout age (8-13).
All comments are reviewed with this audience in mind. Inappropriate comments and comments containing bad language will be removed (there is no way to edit out bad words). Spammers and very offensive material will be reported and removed. 

Comments posted to recent articles will  appear immeadiately and will be reviewed.  Comments posted to older articles will be held for review.

The following are subject to rejection:

• Obvious product advertisements (and additionally reported)
• Offensive languages (and potentially reported)
  
• Personal attacks and "flames"
• Random nonsense (possible testing by spammers)
• Unsolicited and off topic
• Unreachable links

If a post is otherwise worthwhile, I may choose to re-post and delete individual bad words.

I will attempt to be reasonable, if there is a discussion about a type of product. Simple and informative posts about something in the same class of product and discussions of pros and cons of these products are expected.

I reserve the right to revise this policy without notice, reinstate comment moderation or take other actions to control spam/offensive material.

And to the spammers who wanted us to know about your alleged anti-virus solution, weight loss product, and enhancements Now you know. BTW, your blogger ID and all your links were reported as abuse.

Scouts in Space (not kidding)

I came across this article on scouts in space by a leader of 1st Avoca Beach Scouts just north of Sydney in New South Wales Australia!

Of the 294 men and women selected to be astronauts since 1959 to 2005, more than 180 have been Scouts.

and ...

Astonishingly, 11 of the 12 men to have walked on the moon were Scouts.

The first man on the moon, Neil Armstrong, was a Scout and ...

What’s more, Armstrong had carried the World Scout Badge with him on his historic mission.

Update: At least 22 of them were women, here.

Snow Moon Eclipse - simple astrophotography

The night of the BP banquet also coincided with the Snow Moon and a lunar eclipse. As we were leaving the banquet, the shadow of the Earth had just begun to take a bite out of the moon.

I wanted to try and photograph the eclipse as simply as possible. Using just a camera tripod and digital cameras setup for self-timed exposures to reduce vibration. I was able to catch the Moon framed by Regulus (above) and Saturn (lower left).

The photograph was taken with a Nikon 995 digital camera in manual mode (while Nikon makes wonderful cameras with great optics, I could go off on a nice rant about the user interface). It's the best one of a series taken with maximum aperture, maximum optical zoom, and exposures of between 2 and 8 seconds (I believe this is either a 4 or 8 second exposure). It was also taken from my driveway with all the light pollution of Toronto's west end.

There is a nice composite exposure of the eclipse over here at Visual Astronomy. And another over here at Universe Today.

There was also an article on "What they don't tell you about" lunar eclipses at over here at Breaking News for Sky Afficionados.