Thursday, 23 February 2017

A Trip to the Dominion Radio Telescope Observatory

A Trip to the Dominion Radio Telescope Observatory

While visiting a friend in the Okanagan region of British Columbia, Canada region a few months ago (Nov 2016), we drove by the Dominion Radio Telescope Observatory.  Though it wasn’t open to the public that day, we were allowed to go into the grounds on foot and look at the telescopes (from a distance), as well as read some of the literature posted outside, describing the research being done. It was a nice opportunity to look around the site, and see some of these devices from fairly close up.  We also took a few pictures, which are reproduced in this blog.

It also fit in well with my own astrophysical interests, and my son’s work during his PhD at McGill.  His work focused primarily on X-ray astrophysics (neutron stars, magnetars), but he often calibrated these results with radio telescope results, and had co-authors on papers from the radio astronomy world.  And, as a finishing touch, Dodecahedron Books will publish a humorous Science Fiction story later this year, which prominently features the famous Arecibo Radio Telescope in Puerto Rico, and touches on SETI and the Zoo Hypothesis.

Main Radio Telescope Dishes at the Dominion Observatory 

First off, what is a radio telescope, and what is radio astronomy (or astrophysics)?  Basically, a radio telescope is just a large reflective dish, that gathers long wave length electro-magnetic radiation, and focuses it in a small detector region, which captures the signal, boosts it and stores it for further analysis.  (That’s essentially what an optical telescope does as well, but at a shorter wavelength.)  The radio signal is then analyzed for such features as the strength of the radio waves, the location in the sky from which they emanate, the frequency spectrum of the signal, any periodic features it might have, dispersion of the signal, and so forth. From those results, the nature of the originating body and the medium through which the radiation has travelled can be inferred.

Some Intelligent Life at the Observatory, though not SETI

Note that a lot of SETI (Search for Extra Terrestrial Intelligence) research has been done via radio telescopes – that’s probably what they are most famous for in the public mind, because of books and movies like Carl Sagan’s “Contact” (good book, good movie, by the way).

Close-up of a Radio Dish

Radio telescopes are big, because radio waves are big.  Radio waves can be anywhere from millimeters to kilometers, so the radio telescopes must be correspondingly big as well.  After all, a telescope that was smaller than the wavelengths it was meant to detect wouldn’t be of much use (wouldn’t have resolving power).  That’s also the reason that optical microscopes can’t be used on very tiny things, like viruses, for which the much more sensitive scanning electron microscope is used.

In addition to the issue of the size of the wavelength requiring a large dish for resolving power, it is also needed because a large wavelength doesn’t carry much energy.  So, a big dish is needed to ensure that enough energy is captured to produce a useful signal to noise ratio.

The biggest dish at this observatory is 26 meters across.  For comparison, though, Arecibo is 300 meters in diameter, and there is now a 500-meter dish in China.  However, the dish at the Dominion observatory can move, and track objects in the sky.  The really large dishes like Arecibo are stationary, built into natural “bowl” land formations.  They are therefore limited to scanning only part of the sky – essentially the part that happens to be above them at any time of the year (though, over a solar cycle that can cover a lot of sky).

The 26-meter dish primarily studies 21 cm radio waves.  It “sees” an area about the size of the full moon (half a degree or so).  It is very useful for studying interstellar gas clouds, such as those in star-forming nebulae.  This helps us to understand the processes of star formation, and therefore our own solar system’s origin.

Some of the photos above show radio telescopes on railway tracks.  There are four of them (though Wiki says seven), each 9 meters in diameter, that they can be moved on the tracks, relative to each other. This gives the effect of a very large telescope, equivalent to one 600 meters in diameter, once some clever electronics and digital signal processing is performed.  This “aperture synthesis” telescope has been used for various purposes, such as mapping large objects like the Andromeda galaxy.

Linear Array of Cylindrical Antennae.

There is also something called the 22 megahertz “T” antenna, which is reminiscent of the sort of dipole array that was used by Jocelyn Bell to discover the first pulsar.  It was used in the past for full-sky mapping.
There is also a small radio telescope dedicated to solar observations.  That, along with a worldwide system of such scopes, helps to provide predictions and warnings of solar events (bursts of high energy particles) that can affect communication systems and other infrastructure on the Earth, or in orbit.

Finally, there is an array of four cylindrical reflector antennae, each 100 meters long and 20 meters wide.  They are being used in an experiment to measure the cosmological red-shift of the 21-cm line of neutral hydrogen, which will give us a better idea of the history of the expansion of the universe itself.

Note that the observatory is a bit difficult to find, as it is somewhat off the beaten track.  Also, you have to be very careful about stray electromagnetic signals, even from objects as seemingly innocuous as a car engine or a cell phone, if you visit.  After all, these are extremely sensitive instruments, and it doesn’t take much to create a bit of radio interference that they can detect.  

Dominion Radio Astrophysical Observatory:
Dodecahedron Books, field notes and photos


Now that you have read some real science (astronomy and astrophysics), you should read some science fiction.  Either of the Kati of Terra series or the Witch’s Stones series would be excellent choices.  Alternatively, you could try the short story “The Magnetic Anomaly”, which has lots of physics, and even some Fourier analysis.  :)

Kati of Terra

How about trying Kati of Terra, the 3-novel story of a feisty young Earth woman, making her way in that big, bad, beautiful universe out there.  

The Witches’ Stones

Or, you might prefer, the trilogy of the Witches’ Stones (they’re psychic aliens, not actual witches), which follows the interactions of a future Earth confederation, an opposing galactic power, and the Witches of Kordea.  It features Sarah Mackenzie, another feisty young Earth woman (they’re the most interesting type – the novelist who wrote the books is pretty feisty, too).

The Magnetic Anomaly: A Science Fiction Story

“A geophysical crew went into the Canadian north. There were some regrettable accidents among a few ex-military who had become geophysical contractors after their service in the forces. A young man and young woman went temporarily mad from the stress of seeing that. They imagined things, terrible things. But both are known to have vivid imaginations; we have childhood records to verify that. It was all very sad. That’s the official story.” 

Thursday, 16 February 2017

Three Travel Stories, Free on Amazon this Weekend (Feb 16-20, 2017)

Three Travel Stories, Free on Amazon this Weekend (Feb 16-20, 2017)

Drive, bike or walk – your choice, with three different travel stories free on Kindle this week. Normally, they go for 99 cents each, but you can get them all for free, and start thinking of your next travel adventure.

On the Road with Bronco Billy

What follows is an account of a ten day journey through western North America during a working trip, delivering lumber from Edmonton Alberta to Dallas Texas, and returning with oilfield equipment. The writer had the opportunity to accompany a friend who is a professional truck driver, which he eagerly accepted. He works as a statistician for the University of Alberta, and is therefore is generally confined to desk, chair, and computer. The chance to see the world from the cab of a truck, and be immersed in the truck driving culture was intriguing. In early May 1997 they hit the road.

Some time has passed since this journal was written and many things have changed since the late 1990’s. That renders the journey as not just a geographical one, but also a historical account, which I think only increases its interest.

We were fortunate to have an eventful trip - a mechanical breakdown, a near miss from a tornado, and a large-scale flood were among these events. But even without these turns of fate, the drama of the landscape, the close-up view of the trucking lifestyle, and the opportunity to observe the cultural habits of a wide swath of western North America would have been sufficient to fill up an interesting journal.

The travelogue is about 20,000 words, about 60 to 90 minutes of reading, at typical reading speeds.

A Ride on the Kettle Valley Rail-Trail

The Kettle Valley Rail Trail is one of the longest and most scenic biking and hiking trails in Canada. It covers a good stretch of the south-central interior of British Columbia, about 600 kilometers of scenic countryside. British Columbia is one of the most beautiful areas of Canada, which is itself a beautiful country, ideal for those who appreciate natural splendour and achievable adventure in the great outdoors.

The trail passes through a great variety of geographical and geological regions, from mountains to valleys, along scenic lakes and rivers, to dry near-desert condition grasslands. It often features towering canyons, spanned by a combination of high trestle bridges and long tunnels, as it passes through wild, unpopulated country. At other times, it remains quite low, in populated valleys, alongside spectacular water features such as beautiful Lake Okanagan, an area that is home to hundreds of vineyards, as well as other civilized comforts.

The trail is a nice test of one’s physical fitness, as well as one’s wits and adaptability, as much of it does travel through true wilderness. The views are spectacular, the wildlife is plentiful and the people are friendly. What more could one ask for?

What follows is a journal of two summers of adventure, biking most of the trail in the late 1990s. It is about 33,000 words in length (2 to 3 hours reading), and contains numerous photographs of the trail. There are also sections containing a brief history of the trail, geology, flora and fauna, and associated information.

After reading this account, you should have a good sense of whether the trail is right for you. If you do decide to ride the trail, it will be an experience you will never forget.

A Walk on the Juan de Fuca Marine Trail

The Juan De Fuca Marine is considered by many to be one of Canada’s finest hiking trails. It hugs the southwestern shore of Vancouver Island, between Jordan River and Port Renfrew for a distance of about 48 kilometres. Like its (perhaps) more famous neighbouring hiking trail just to the north, The West Coast Trail, it features both beach and forest hiking along a rugged coastline. The hiking is a nice test of one’s fitness, the views are spectacular, the wildlife (marine and forest) is plentiful and the people are friendly. What more could one ask for?

What follows is a journal of a five day trip, taken in early September of 2002. It is about 13,000 words in length (60 to 90 minutes reading), and contains numerous photographs of the trail. There are also sections containing a brief history of the trail, geology, flora and fauna, and associated information.