Astronotes-Oct-2009

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Astronotes-Oct2009-Cover.jpg
Manuel Fernandez and Manuel Jr. enjoy a peak at the Sun with volunteer Ken Whitnall at a public outreach event at the Carp Library on September 12, 2009.

A New Adventure Begins

by Debra Ceravolo, Astronotes Editor I have enjoyed getting involved with many aspects of the RASC Ottawa Centre since I joined back in 1995. Everyone I met made me feel welcomed and encouraged me to participate in whatever I was interested in. I started out as the Public Outreach Coordinator and eventually found my way into the inner workings of the Council where I stayed on as a Councillor for several years. When I was nominated for Vice-President, I couldn’t say no to a new challenge. I then had the honour of being the President during our 100 year anniversary in which I chaired the National RASC General Assembly to help us celebrate. Now as my term of National Rep is coming to a close, the position of AstroNotes Editor presented itself and of course, I couldn’t say no to a new challenge. So here I stand, your new AstroNotes Editor.

But I need your help, Ottawa Centre. The AstroNotes is your newsletter and so please feel free to send me your thoughts, reports, images, observations and inspirations. I am open to new ideas and have some of my own. I would like to see a variety of articles, short, in depth, scientific, humorous, informative, current events and much more. I look forward to reading and editing each and every one. This is going to be fun. In closing I would like to say thanks to Paul Wefers Bettink for his dedicated service as AstroNotes Editor for the past four years.

Contents


News across the RASC

Sometimes we forget that we are part of a larger Society. One that spans the country. There are 29 Centres now that belong to the RASC. To keep in touch with some of the exciting things happening within the extended family of the RASC, we have set aside a section in AstroNotes each month dedicated to just that. You can also visit http://www.rasc.ca/news/ to find out more. Here are a few examples of what’s going on:

Save the date for the 2010 RASC General Assembly!

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The 2010 General Assembly organizing committee invites you to save the weekend of July 1st-4th, 2010 for the RASC 2010 GA. Find out what the New Brunswick Centre has in store for you as they host their first ever General Assembly! For more information visit www.rasc.ca/ga2010. (Photo courtesy: Paul Gray, New Brunswick Centre)

“Looking Up” now available on-line

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Looking Up, the thoroughly researched and entertainingly written “official” history of the RASC, is now available again. Long out-of-print, and difficult to obtain used, the book has been digitized in its entirety as an initiative of the RASC National History Committee.

Looking Up covers the story of the RASC from its pre-history in the later 19th-century up to 1994, and is profusely illustrated. The author, R. Peter Broughton, a long-time RASC member and past president of the Society, is a recognized authority on the history of astronomy in Canada.

The URL is http://www.rasc.ca/publications/lookingup/index.shtml.

Ottawa Centre meeting report- September 4, 2009

By Estelle Rother, Recorder Members’ observation reports included telescope viewing of Jupiter and its moons from Attilla Danko while at Starfest, Gary Boyle showed his images of the Jovian transits in August. Rolf Meier presented an animation of the shadows of Europa and Ganymede as well as images of Jupiter and Mars. Paul Comision acquired an image of last month’s challenge object, NGC 5866 in Draco. He followed this with NGC 6618 and M17. Sanjeev Sivarulrasa showed us five images that included M31, the North American Nebula and the Pelican Nebula. John Thompson showed his image of his first planned meteor capture. Brian McCullough had a sketch of a grazing occultation of Antares by the Moon on August 27.

Pierre Martin gave a report on the above average Perseid Meteor Shower. Thanks to Saturn for directing the dusty core from the Perseids towards us, it was the best show since the early 1990’s. There were 3 peaks that ranged from 4am on August 12 to 2 am on August 13. Ottawa had clear skies both nights and the Perseids produced a nice display despite the full Moon.

Steve McIntyre gave a report of what to see in the Ottawa skies in September. There is plenty to observe as the sky gets dark earlier, the temperature is moderate and mosquitoes are less annoying. If you face south at the time of astronomical sunset, you will see the constellation Bootes with Arcturus, the brightest star, setting in the west. Continuing towards the east, observe Corona Borealis, then Hercules which is home to the globular cluster M13, followed by Cygnus with Ophiuchus below it. Sagittarius is almost due south and to the east of it is Pisces, then Aquarius, and Capricornus where Jupiter, Neptune and Uranus can be found. Pegasus and Andromeda are rising in the east. Steve suggests observing the Milky Way now. Just sit back and enjoy the view. The most important tool is your lawn chair.

Besides the Moon, Jupiter is the brightest object in the night sky and binoculars will let you see the 4 Galilean moons.

(IYA 2009 is the celebration of Galileo’s first views of Jupiter and its moons through a telescope 400 years ago. This is a good time to dig up a pair of binoculars and see what Galileo saw. – Ed)

Steve mentioned that late on September 2 and early into the morning, Jupiter appeared with no moons. That won’t happen again until 2019. Also, on September 29, Jupiter can be seen a little before sunset 1 degree Southwest of the Moon.

Mike Moghadam and Linda Meier reported on the August 14th Carp Star Party. A combination of good weather, 9 telescopes, 12 volunteers and more than 200 visitors resulted in a successful event. There were many positive comments and Mike thanked everyone who participated. He then talked about upcoming events with the first being public solar viewing held at the Carp Library on September 12 followed by a star party in the evening. The next event would be held on Friday, October 9 with October 10 and October 16 as backup rain dates. Linda Meier showed a video of arriving at the site, the bookstore in the library (the Carp Book Corner) and the observing site.

Bob Olson reported on his trip to the Winter Star Party in February in the Florida Keys. He said it was hard to beat observing in shorts in the middle of winter. He enjoyed getting together with other astro photographers. Bob showed some of his own images and more taken by other photographers including Attilla Danko, Paul Sheppard, Jon Talbot and Dean Schwatzenberg. Between 600 and 700 people attended the event which was too many people in such a small area but the vendor area was excellent.

After a short break and the draw for door prizes, we heard from Tim Cole describing the astronomy courses and events taking place at the Museum of Science and Technology. For more information visit http://www.sciencetech.technomuses.ca/english/whatson/astronomy-programs.cfm

Chuck O’Dale continued his series of “Really Big Holes in the Ground” with a talk about the St. Martin meteorite crater. Read about Chuck’s crater adventure in this issue on the following page.

Last month’s lunar challenge was to create a multimedia Moon. Brian Mc- Cullough demonstrated his solution with the plate from inside a microwave oven. He put on a pair of gloves and using white mini marshmallows and some coated with cocoa, he created his Moon. Using a real map of the Moon, he placed the white marshmallows where the highlands are located. He then used the dark marshmallows as the basalt of the mares. Brian placed Reeses Minis Apollo Landers on the marshmallow Moon where Apollo 11, 12, 14, 15, 16 and 17 had landed. The completed project did look like the Moon.

Thanks to Anne and Art Fraser for the after meeting refreshments.

Geological Effect of Bolide Impacts on this Planet

By Chuck O’Dale

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In this article I will describe the geological effects of bolide impacts on this planet that I have researched and/or personally explored. My interest in this subject dates back to the 1950’s when I first saw Dr. Meen from the Royal Ontario Museum describe his exploration of the Pingualuit (then Chubb) impact structure. My interest was rekindled in the 1990’s with the exploration of one of the most fascinating craters to study on this planet, the Chicxulub Crater. One of the original researchers of this structure was Dr. A. Hildebrand who investigated the KT boundary outcrop on a side valley of the Brazos River in Texas. It was there that the first tsunami deposit from the impact was recognized and the data documented was used to find the crater location (Alvarez W. 1997). The Chicxulub Crater has a prominent ring of cenotes circling the impact structure. The cenotes outline the crater rim even though the crater itself is buried under ~ 1km of sediment.
The Chesapeake Impact Crater
I will document two other structures, the Chesapeake and St. Martin Meteorite Craters, which are similarly buried. They are totally unrelated to each other with respect to time, size and place, but like Chicxulub, have many similar structural and stratigraphic features that have affected the geology around them. I will document these geological anomalies and conclude with a hypothesis based on the empirical data described here.

The Chesapeake Bay Impact Crater

About 35 million years ago a bolide 3-5 kilometres in diameter impacted the western Atlantic Ocean on a shallow shelf, creating the Chesapeake Bay impact crater. At this time the sea level was much higher and the coastline was in the vicinity of Richmond, VA. The crater is approximately 200 km Southeast of Washington, D.C. and is now buried 300-500 metres beneath the southern part of Chesapeake Bay. Analysis of seismic profiling has determined that the crater is 85km in diameter and 1.3km deep. It is a complex peak-ring crater with an inner and outer rim, a relatively flat-floored annular trough, and an inner basin that penetrates the basement. The inner basin includes a central uplift surrounded by a series of concentric valleys and ridges.

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A 1.3km thick rubble bed of impact breccia fills the crater and forms a thin ejecta blanket around it. Compaction of this breccia produced a subsidence differential, causing the land surface over the breccia to remain lower than the land surface over sediments outside the crater. Another consequence of the impact is that all ground-water aquifers were truncated and excavated by the impact. In place of those aquifers is a reservoir of briny water that is 1.5 times saltier than normal seawater.

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Most rivers in the area, like the Rappahannock, flow southeastward to the Atlantic. In contrast, the York and James rivers make sharp turns to the Northeast where the outer rim of the crater traverses the lower York-James Peninsula. The abrupt diversions of the lower courses of the James and York Rivers (indicated by the small circles in the map above) coincide with the Chesapeake crater rim. The cause of these diversions is the differential subsidence of the outlaying country rock compared to the breccia within the Chesapeake Bay impact crater forcing a structural sag over the subsiding breccia. The river diversions are at the “rim” of this sag.

Chesapeake Crater References

  1. D.S. Powars and T.S. Bruce, USGS, Feb. 2000; THE EFFECTS OF THE CHESAPEAKE BAY IMPACT CRATER ON THE GEOLOGICAL FRAMEWORK AND CORRELATION OF HYDROGEOLOGIC UNITS OF THE LOWER YORK-JAMES PENINSULA, VIRGINIA
  2. Poag C. Wylie 1999, Chesapeake Invader

The St Martin Meteorite Impact Crater

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About 219 million years ago a bolide ~2 kilometres in diameter impacted north of Lake St. Martin between Lake Winnipeg to the east and Lake Manitoba to the west. At the time of impact the area was covered by ancient seas and dinosaurs ruled the Earth. The bolide impacted in Ordovician to Devonian sandstones overlying Archean-aged granite of the Superior Province of the Canadian Shield. The crater is now buried by over 100 m of Jurassic red beds from these ancient seas. In recent times glacial drift has added an additional covering layer. This “cover” has made St. Martin one of the best preserved craters on this planet. Drilling and geophysical data has revealed a peripheral depression of 21.5 km in diameter and an outer limit of structural disturbance with a diameter of 38.5 km. The structure is classified as a complex crater with a central uplifted area. The uplifted area includes a surrounding annular trough. Outcrops of Precambrian granite at the crater’s outer limit may indicate an inner ring of a larger central peak basin crater.

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Drilling has revealed carbonate breccia, granitic breccia, suevitic breccias and impact melt rocks under the impact structure. A study (2007) detailed in the journal Geology suggests meteor impacts with the Earth can produce effects of a more subtle and insidious kind than just catastrophic extinction.

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The scientists said a good example was found at the Canadian town of Gypsumville, Manitoba, located within the St. Martin impact crater. Domestic wells in the town have elevated salinity, sulfate and fluoride concentrations. The groundwater with elevated fluoride is shown to occur exclusively within the impact structure, and the study is thought to be the first to document enhanced groundwater fluoride concentrations associated with impact structures.

The circle, superimposed on this aeronautical chart of the impact area, indicates the maximum geological extension of the St. Martin impact crater. Note on the chart that on the North East point of the crater the Dauphin River has an almost 180° diversion. This extreme change in direction of the river coincides with the North East extension of the crater rim. This abrupt diversion phenomenon is also documented in the Chesapeake impact structure.

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My hypothesis is that the cause of this extreme diversion (Image left) of the Dauphin River at the St. Martin crater rim is a result of the subsidence differential of the outlaying bedrock compared to the breccia fill within the impact structure.

To my knowledge, there is no other report describing the cause of this river’s diversion at this specific location.

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The Dauphin River then follows the crater rim to the East and flows into Lake Winnipeg (Image right).

St. Martin Crater References

  1. Grieve, R.A.F. 2006, Impact Structures in Canada (Geological Association of Canada).
  2. Geology (Lower Hutt, New Zealand (UPI) Jan 23, 2007).

(Chuck O’Dale, Ottawa Centre Past-President and National Rep. has combined his engineering skills with his hobbies of astronomy, geology, and flying to document his explorations of impact structures on this planet.)

RASC Ottawa Centre Annual Dinner - November 13, 2009

By Al Scott: Vice-President

The annual Ottawa RASC dinner will take place on Friday, November 13th at the Algonquin College Salon D with a cash bar starting at 6pm, dinner at 7pm. Tickets are available from Alan Scott for only $40. Great food, astronomical door prizes, and an engaging distinguished speaker are among the highlights of the evening.

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Professor René Doyon is a researcher at the Université de Montréal and a specialist in infrared astronomy, as well as the development of infrared instrumentation in general (camera and spectrometer), especially for detection of exoplanets by direct imagery. He is Director of Infrared Observation Programs dedicated to researching exoplanets, brown dwarfs and young low-mass stars. He is also Director of the Mont Mégantic Observatory near Sherbrooke Quebec. Prof. Doyon is Senior Researcher of the Canadian scientific team for the James Webb Space Telescope Tunable Filter Imager. He is also a member of the science teams on the Gemini Planet Imager (GPI), and the Flamingos-2 Tandem Tunable Etalon (F2T2).

In 2008, Prof. Doyon, along with two other Quebec astronomers, Christian Marois and David Lafrenière, succeeded in acquiring the first images of a planetary system other than our own. The work included applying innovative image processing techniques to archived Hubble data.

For tickets by mail, please send a stamped self-addressed envelope along with a cheque for $40/ticket to:

Alan Scott
214 Muldoon Rd.,
Kemptville ON.,
K0G 1J0

Observing Challenges of the Month

September 2009 Challenges:

Lunar: Murray Campbell’s Pick

Murray chose a site that had nothing to do with Apollo 11. Look for a two kilometre dent in Mons Hadley in the Apennines Mountain area. If you have a ginormous scope, you could try to find the Apollo 15 Lander.

Deep Sky: Paul Comision’s Pick

Observe or image Einstein’s Cross in Pegasus. This is CGCG378-15 (Catalogue of Galaxies and Clusters of Galaxies). This is the only chance amateurs have to see gravitational lensing. You will need at least a 20 inch scope to observe it or a 12 - 14 inch scope for imaging.

Each month, members who complete these challenges present their reports at Centre meetings while the new challenges of the next month are announced.

Mars is Growing

by Rolf Meier

Not literally of course! But finally Mars is growing in apparent size and gaining altitude in a dark sky after being tiny and lost in the glare of the sun for over a year.

Mars observers anxiously await the few months out of every 26 when Mars shows features as seen through a telescope. That time is starting now, as the apparent diameter has now exceeded 6 arc-seconds. Even so, Mars will attain a maximum size of merely 14.1 arc-seconds early in 2010 around the time of its opposition, close to the smallest opposition diameter possible. Contrast this with a maximum size of over 25 arc-seconds at the 2003 opposition.

But the good news for Ottawa observers is that Mars is much higher in the sky this year, which reduces the impairments due to poor seeing. At dawn in October, Mars will be over 50 degrees up.

Here are some images I obtained recently. With today’s technology it is possible to detect planetary features more easily with imaging than can be captured in a drawing. The images were taken about a month apart. In that time, the same features slowly make their way around the planet if observed at the same time due the slightly slower Martian day. Notice how the tilt of the planet has changed.

The images were taken with my C14 telescope and SkyNyx camera made by Lumenera.

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Member’s Images

M45 - The Pleiades by Bob Olson

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This image of the Pleiades, AKA, The Seven Sisters, is an LRGB 4 panel mosaic with a total exposure time of 8 hours. The camera used was a Starlight SXV-H9 with an Optec LRGB filter wheel on a Tele Vue 76 refractor with a Tele Vue .8 reducer/flattener.

Andromeda Galaxy and M110 by Bob Olson

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The Andromeda Galaxy rises in the east in the fall evenings and can be seen naked eye in dark skies. This 4 panel mosaic has a total exposure time of 6.6 hours and was taken with a Starlight MX916 CCD camera and Tele View 76 refractor.

Tycho - by Gary Boyle

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This image of Tycho Crater was taken when the Moon was nearly full using a Meade LX 200 at f/6.3 and a ToUcam web cam with a green filter. Processed in Registax 5 and Photoshop elements. A great target for trick-or-treaters on Halloween.

Jupiter Impact - Pul Klauniger

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Around July 19th, 2009, something slammed into Jupiter causing a large bruise on the surface clouds of the planet. It was probably an asteroid impact. Paul Klauniger captured this new dark spot with the Museum’s 15” refractor.

Astro Quote of the Month

“Space isn’t remote at all. It’s only an hour’s drive away if your car could go straight upwards.”

-Fred Hoyle- English Astronomer and Author
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