Download PDF version:
The Newsletter of the Ottawa Centre, RASC
|Volume 59 – No. 2 – February 2020|
First of all, I would like to apologize for the delay in getting this issue out to you. It has been a very busy month and to compound the issue, a low energy month. But hey, the days are getting longer, and the sun is actually out, and it is mild. Can Spring and the Messier Marathon be far behind?
Speaking of Messier Marathons, the FLO Members Star Party in March is on the best weekend for a Messier Marathon. Now is a great time to start planning yours. If you have never done one, or if you have never been to the FLO or one of our member star parties, March might be a good one to plan to attend.
My Assistant Editor, Doug Fleming seems to travel a lot so sometimes he is not here to perform his duties as Assistant. The good news however is that he always brings us an interesting astronomy related article from wherever he goes. Last year it was China, this year it is Scotland. And I hear that Chile and Australia may be in the offing!
Also in this issue, our Web Master, Mick Wilson shares with us a project that he is working on to make our website an easy to use treasure trove. Simon Hamner has a really interesting book review for us on what he feels is a must-read book on exoplanets.
AS always, I hope you enjoy this issue and if you have any comments, criticisms or contributions, please share them with me.
Full super moon on February 9 – known as the Full Hunger Moon
Comet PanSTARRS C/2017 T2 will be visible in the evening skies. Its perihelion is on May 8th at which point it should be magnitude 8
Rise/Set 08:12/18:20 -> 06:12/17:09
February 10 – Greatest Eastern Elongation
Look for the planet in the western sky just after sunset.
Visible early evening.
Rise/Set 09:07/20:37 -> 08:14/21:42
Visible just before sunrise.
Rise/Set 04:15/12:50 -> 03:51/12:21
Visible just before sunrise.
Rise/Set 05:57/14:35 -> 04:28/13:13
Visible before sunrise later in the month.
Rise/Set 06:38/15:32 -> 04:58/13:57
Visible first part of the night.
Rise/Set 10:30/00:11 -> 08:42/22:21
Visible first part of night first half of the month.
Rise/Set 08:56/20:04 -> 07:08/18:19
Astronomy on Calton Hill in Edinburgh
I was lucky enough to travel around the UK last October. I took in the Isle of Skye, Glasgow, Hadrian’s Wall, Greenwich, Epping and the Cotswolds. Great walking, wonderfully efficient train services (get the seniors’ Eurail pass if it is still offered) and cheap digs (check out the Youth Hostel Association: one can now rent entire rooms and avoid dormitories, especially in low tourist seasons).
Anyway, I thought that I would report on a very innovative astronomically-orientated art exhibit on top of Calton Hill in Edinburgh. The hill is central to the history and current life of the city. The Scottish Parliament Building, Holyrood Palace and monuments to Robert Burns and Scottish independence activists are at the hill’s foot.
The top of Calton Hill is the site of the City Observatory, which once housed a 22-inch refractor, a 6-inch refractor, an operational 6.4-inch transit telescope and a set of deep-earth thermometers. The site also has a number of impressive monuments, a high-end restaurant and a series of walks (one of which is dedicated to the philosopher David Hume, whose grave is nearby).
The hill, now a UNESCO World Heritage Site, was first occupied as an observatory by Thomas Short in 1776 and was added to by numerous other figures of the Scottish Enlightenment, most notably by John Playfair, president of the Edinburgh Astronomical Institution and Thomas Henderson, the First Astronomer Royal for Scotland. The site has had quite a tumultuous history over the years involving various ownership struggles.
No troubles now, however! Since 2013, a group of multimedia artists, called The Collective, has worked in conjunction with the City of Edinburgh Council and the Astronomical Institution to restore and repurpose the observatory site into an exhibition space for contemporary astronomically-orientated art.
I spoke to several of the artists in residence and took in some of the exhibits. VERY impressive, even to someone with little knowledge of modern art, such as myself.
As their website notes, The Collective, “brings people together to look at, think about and produce contemporary art in a new kind of city observatory. Our programme of exhibitions, walks, and events presents contemporary art in all its diversity. We provide artists with the opportunity to make new work and audiences the chance to see it here first. By inspiring, engaging with, and learning from the people and groups around us, we aim to contribute to local, national, and international conversations.”
I’ve copied a Wikimedia image of Calton Hill by Safffron Blaze below (which is far better than the ones I took with my little PowerShot).
On the far right is the 1826 Neo-Greek National Monument, an unfinished project celebrating Edinburgh’s reputation as the Athens of the North during the Scottish Enlightenment. A little to the left is the 1895 green copper-roofed City Dome, which once held the 22-inch Buckingham Telescope, at that time the largest refractor in the world. It is now on display at the Scottish National Museum. The Dome now is an impressive exhibition hall. The 1807 Nelson Tower, designed to resemble a mariner’s pocket telescope, is slightly to the left of the centre in the photo. It was once used to provide accurate times for local shipping. Each day at 1:00pm a large white ball drops down its flagstaff, an event synchronised with a cannon shot from Edinburgh Castle. To the left of the tower is the Transit House, previously the residence of the City Astronomer (now a conference centre and high-end guest house). Behind the Tower, you can just make out the white dome of the City Observatory, which has a library, exhibition space and gift shop. It is here that the Transit telescope is displayed.
By Saffron Blaze - Own work, CC BY 3.0, https://commons.wikimedia.org/w/index.php?curid=18402255
My own Canon Powershot a720 IS picture of the City Observatory
Below is my Powershot photo of the Transit Telescope on display in the City Observatory. It was made in Hamburg by Repsold in 1831. You can make out the meridian-aligned roof slot (no longer operational).
In the background of the photo you can make out a Cooke refractor donated by William McEwan in 1896. State of the art at that time.
Below is a photo of the Buckingham Telescope, with William Peck, the City Astronomer in the 1920’s. https://www.flickr.com/photos/finnegansword/5479781471
Powershot image of City Dome
Powershot image of David Hume walk
I’d like to encourage you to check out the above links that can give you more information about the site and the innovative art produced by The Collective. Or better yet, find an excuse like I did to go to Calton Hill as part of a visit to Scotland and Edinburgh: wonderous places!
For more information about the work of The Collective, go to: https://www.collective-edinburgh.art/
A better view of the City Observatory by Andrew Shiva is through this link: https://commons.wikimedia.org/w/index.php?curid=51680156
For information on Cooke telescopes see:
RASC Ottawa website and AstroNotes On-line
Mick Wilson firstname.lastname@example.org
In 2018 I volunteered to manage the RASC Ottawa Centre web site. What I did not anticipate was becoming the RASC Ottawa Centre archaeologist, Keeper of the Sacred Texts, and Seeker of Lost Treasures.
When Taras Rabarskyi was handing over the reins (and admin password) he mentioned that an intern had been scanning back issues of AstroNotes and - lo! - there was an archive stretching back to 1963 ... 55 years and counting.
That's long enough to include references to what the Centre was to do as Canada celebrated its centenary. That's long enough that names like Fred Lossing, Stan Mott and Ted Bean applied to active players rather than to memoria. That's back when phone numbers only had seven digits, when there were neither postcodes nor metric units.
AstroNotes was a news exchange for people who were grinding their own mirrors, photographing on film and plates, and constructing their own setting circles. There's one issue from 1971 that contains a plea for cheap punch cards to help reduce data gathered by observers of meteors ... now, that’s history!
I was hooked. I set my sights on answering the question of "What's the web site for?" with "If nothing else, being the window on RASC Ottawa members' accumulated knowledge and experience."
So, What was Wrong? What Needed Fixing?
The stalwart efforts of the above-mentioned un-named intern notwithstanding, the scans were in a state that was akin to having copies in box files on a shelf i.e. only useful if you knew what you were looking for. No index. No catalogue. No ability to find or discover anything. The content was virtually hidden from web searches. There was no chance that a web user interested in, say, use of nebula filters would ever discover that RASC Ottawa exists and that its members have at different times offered considerable advice on such matters.
I decided to fix this.
Meanwhile, a second shortcoming became apparent, another on-line resource was being under-employed. To whit, the monthly meeting videos were being posted to the web on and off for over 10 years. Again, here was an invaluable resource only useful if you knew what you were looking for - unindexed, uncatalogued, virtually impossible to find as a pleasant surprise.
Light-bulb moment! Each issue of AstroNotes usually contains the text or images from the previous month's presentations. Time to kill two birds with one stone: make the contents of AstroNotes more discoverable and use that to build descriptions for the meeting recordings without having to convince some sucker to write them.
What's going on?
I am work-averse, so am looking for ways to expend the least effort to expand the outreach value of RASC Ottawa's assets.
As I write this, I am working my way through AstroNotes forward from 1963, extracting text from the scanned AstroNotes and building that into web pages. The original PDF files are still available but augmented with super powers that I have already added to the site so that web search services can better find stuff and lead people to RASC and to the Ottawa Centre. I am up to 1971 and you can see - for example, at at https://ottawa.rasc.ca/astronotes/1971-02 - how things are going.
You will (some day soon) be able to discover the contents of all AstroNotes through web, read them online, and still able to access the scans of the original newsletters. The content of the PDF files is now at least legible on-screen, while the "File_Public" link lets you click back to the (original) scanned newsletter... something like this:
The scans of the original newsletters remain available in downloadable PDF files.
I am also working backward from the present so as to balance historical content with the current and relevant. AstroNotes editor Gordon Webster and I are inching closer to having something like a production line that can take each issue hot off the press and have it up on web, searchable and discoverable for less than colossal effort. We are currently back to 2015. As that work proceeds, I am - where possible - extracting summary text to help the search engines find the monthly meeting videos. https://ottawa.rasc.ca/content/february-2019-meeting-recording gives you an idea of the New Look.
AstroNotes now also links with the appropriate monthly meeting recordings and makes them easier to find as well.
Only another 44 years of backlog to go!
Where are We?
A new web page at https://ottawa.rasc.ca/content/astronotes-available-online shows progress-to-date in getting AstroNotes searchable and discoverable.
The yellow blocks marked with P are pending, as in we know we have the PDF files for those issues, but they are yet to be "mined". You can access the PDFs through https://ottawa.rasc.ca/astronotes .
The light green blocks are those that have been mined and are already available, with the number showing the volume and issues.
Dark green blocks are Missing In Action - known to have existed but not (yet) available in the archives (hint! hint!). There are a number of whole years that are MIA, marked with the embarrassing pink blocks.
Blank blocks show where AstroNotes is known not to have been issued.
Anyone who has back copies that can help fill these blanks will be bribed to make them available for scanning, uploading, and preservation in the library.
Progressively, I intend to make this a clickable index but, for now....
What's in the Pipeline?
- Work continues to mine the PDF files. Volunteers are welcome to assist (he said hopefully but shamelessly).
- Many issues marked with in light as "done" could till use work to improve their on-line presentation and readability. More volunteers would be welcome.
- Also, some of the scan-to-text translations are less than perfect, with word s sepa rat ed with extra spaces or, sometimes, wordsr uni into each other. You can point out such glitches to me to correct or, possibly, just maybe volunteer to correct them, and maybe even search out others. Just a thought.
- Building an online gallery of contributed images, possible now that I have access to Gordon's original AstroNotes documents and the image files. All contributions will be attributed, and contributors will be encouraged to provide background information on means and methods by which images were captured.
- Beyond AstroNotes? Well, if we're still doing Monthly Challenges then I think they'd make another eye-catching contribution to the web site.
- Improved members' information - skills, experience, weird hobbies, that sort of thing.
- Suggestions as submitted.
Thanks for your attention and thoroughly un-guilted, voluntary effort to support this invaluable effort, and to forge your legacy in the eternal annals of the RASC Ottawa Centre.
The Planet Factory: exoplanets and the search for a second Earth
Bloomsbury Sigma, 2017, 336 pp. ISBN 978-1-4729-1772-0
The search for a second Earth has become a new favourite theme of popular media, encouraged to a significant extent by many of the scientists involved in the research. In the opening lines of the Introduction, The Blind Planet Hunters, Elizabeth Tasker recalls the classical tale of the blind men trying to define an elephant by touching only parts of the beast, which she directly compares to the current state of knowledge of the diversity of planets and planetary systems.
Tasker is an astrophysicist and associate professor at the Japan Aerospace Exploration Agency. Not only does she have a thorough grasp of the subject, she has a delightful, lucid way with words that allows her to successfully communicate an inherently complex message to any interested reader, no matter what their level of science literacy. Her writing style could be described as "astrophysics and planetary science meet Sherlock Holmes". Rather than providing encyclopedic reams of data, she offers an easily understood narrative throughout the text that describes the questions, observations and hypotheses planetary scientists have been and are currently working with. Her intent is to arm the reader with an understanding of the principal mechanisms and processes involved in making planets, highlighting the interplay between the different variables involved, which she explains in elegantly simple terms, commonly drawing on everyday analogies. Then, rather like a mystery whodunnit, for each of the many case studies she presents, she reveals new clues that led planetary science to modify the hypothesis of the moment. The interested reader quickly realises that this is going to be a thoroughly engaging roller-coaster ride and will have trouble putting the book down.
The Introduction clearly explains the science behind the two principle techniques for detecting planets beyond our own Solar System (exoplanets): systematic star wobbles and brightness variations. Tasker then presents planetary science in three parts. Part 1, The Factory Floor, takes us from the planet-forming protoplanetary disc to the rapid (10 million years is fast!) formation of planets. She readily explains the limitations of our knowledge of exactly how this occurs, even in our own Solar System. There's a lot to be considered here: (i) building solid planets by accretion from protoplanetary dust involves interplay between solid particles and gas; (ii) building gas giants - especially their atmospheres - involves interactions between competing gravitational influences, gas temperature, and the role of accretion vs disk instabilities; (iii) building planetary systems involves an understanding of where planets originate within protoplanetary discs, and how planets migrate inwards and outwards, depending on the presence or absence of gas in the disc. It is a testament to Tasker's skill as a teacher that she manages to convey all of this apparent complexity to the lay reader with truly competent ease.
Part 2, Dangerous Planets, presents the spectrum of planet formation theories by applying the theoretical aspects, well explained in Part 1, to a range of case studies. She deftly handles the (Kozai-Lidov) interactions that can occur between orbital ellipticity and inclination via the gravitational interplay between multiple bodies (e.g two stars and a planet) that can lead to all sorts of observed planetary system configurations. Starting with the discovery of "hot Jupiter" exoplanets, that must have migrated in toward their central stars, Tasker reviews the determining factors controlling planet migration, with easily understood explanations of the popular Grand Tack and Nice models. The migration of "hot Jupiters" may be instrumental in the formation of super-Earths and mini-Neptunes, the commonest types of exoplanets observed to date, but it's not that simple: what happened when no "hot Jupiters" are present. This is where Tasker presents her first detailed case study: the planetary system orbiting the star Kepler 11. The purported presence of at least 5 super-Earths but no "hot Jupiter" obliged planetary scientists to look to stellar magnetic fields to explain their observations - until, that is, they realised that all 5 planets were in fact mini-Neptunes ... at which point the problem switched to how to stop the gaseous planets from growing to Jupiter-size and larger. The many other case studies presented follow a similar, easy to follow now-you-see-it-now -you-don't pattern, as in the case of 55 Cancri b, by turn hypothesized to sport a surface ocean, a mantle made of diamonds, a crust made of silicon carbide - although it may be made of molten silicate lava - and a toxic carbon monoxide atmosphere. If that's not enough excitement, the planet's surface temperature may fluctuate between 1000-2700°C, and its size appears to oscillate dramatically over a short time frame. In other case studies, Tasker explains the many disagreeable effects of tidally locking a planet to present the same face to its central star: you would not want to live there!
After rounding off Part 2 with an examination of planets associated with binary star systems and rogue planets with no associated star at all, Tasker turns to examining planets from the perspective of potential life in Part 3, beginning with a detailed examination of the misnamed "habitable" (Tasker prefers temperate) zone. In her accessible narrative style, she presents the Goldilocks Criteria, variables that influence and control the development of a pleasant, inhabitable planet for life as we know it. She explains how greenhouse gases work and why the Earth is located between the Maximum Greenhouse and the Runaway Greenhouse limits within our Solar System, the faint young Sun paradox, and the roles of gravity and magnetic fields in retaining or losing planetary atmospheres. Using the case study of the planetary system around the red dwarf star Gliese 581, that included what the discovery paper described as the "most Earth-like of all known exoplanets" Tasker weaves a cautionary tale of runaway greenhouse environments, primitive atmospheres with no water, tidal locking with major temperature differences on the day and night sides, and the "disappearance" of purported planets that simply weren't there in the first place! Part 3 concludes with, among other fascinating topics, the consequences for habitability of water worlds, frozen moons, and atmospheric collapse on tidally locked "eyeball" planets and ends with a brief examination of the difficulties inherent in detecting life on exoplanets at a distance.
If you read the book this far, you will truly understand its central theme: it's not enough for a planet to be located in its star's "habitable" zone for it to be a second Earth. Personally, I found this book to be both fascinating and enlightening. It is ideally suited to any amateur astronomer interested in planetary science. I strongly recommend it, and at CAN$32.00, the price is right.
Simon Hanmer is a retired geologist with 40 years professional experience, and ~25 years as an amateur astronomer with ongoing interest in planetary geology. A member of the RASC Ottawa chapter, his many presentations on the subject can be found at https://www.simonhanmer52.ca/planetary-geology.html
Monthly Challenge Objects
By Oscar Echeverri
Estelle’s Pick of the Month
International Astronomy Day
is coming!! Make your calendars.
• Saturday, May 2
• Saturday, September 26
Carp Star Parties
• Here is the schedule for our Public Star Parties for the summer. Thanks Paul.
◦ Friday, May 22
◦ Friday June 19
◦ Friday, July 17
◦ Friday August 15
◦ Friday, September 12
◦ Saturday, October 10
FLO Star Party Dates for 2020
Our Ottawa Centre’s Members’ Star Parties at the FLO will continue this summer. If you haven’t attended before, be sure to mark at least one of these dates on your calendar. You are welcome to bring family members or a guest. The GO/NO GO call will be made on the Centre mailing list, about noon the day of the star party
WINTER & SPRING DATES
• Saturday January 25 – Waxing Crescent Moon, 1.1% illumination NO GO
• Friday February 21 – Waning Crescent Moon, 2.8% illumination - GO
• Friday March 20 – Waning Crescent Moon, 10.8% illumination
• Saturday April 25 – Waxing Crescent Moon, 7.3% illumination
• Saturday May 23 – Waxing Crescent Moon, 1.4% illumination
• Saturday June 20 – Day before New Moon, 0.2% illumination
7:30 PM Friday March 6, 2020 at the Canada Aviation and Space Museum (directions). Note there is a $4.00 parking fee for museum parking. The meeting runs until 9:30 pm
PLUS: all our regular meeting features: Ottawa Skies, 10-minute Astronomy News Update, Observation Reports and, of course, the beloved Door Prizes!
All RASC monthly meetings are free and open to members and non-members alike. Refreshments will be available, and this will be a wonderful opportunity to meet new friends who share a common interest and chat in a relaxed, stimulating and fun environment. Please join us!
The Ottawa Centre 2020 Council
President: Mike Moghadam (email@example.com)
Vice President: Stephen Nourse
Secretary: Chris Teron (firstname.lastname@example.org)
Treasurer: David Parfett (email@example.com)
Centre Meeting Chair: Dave Chisholm (firstname.lastname@example.org)
Councillors: Carmen Rush, Gerry Shewan, Jim Sofia
National Council Representatives: Karen Finstad, OPEN
Past President: Tim Cole
2020 Appointed Positions
Membership: Art Fraser
Star Parties: Paul Sadler
Fred Lossing Observatory: Rick Scholes (email@example.com)
Light Pollution Abatement: OPEN
Public Outreach Coordinator: Jean-Sebastien (JS) Gaudet
Hospitality: Art & Anne Fraser
Stan Mott Astronomy Library: Estelle Rother
Ted Bean Telescope Library: Darren Weatherall
Webmaster: Mick Wilson (firstname.lastname@example.org)
AstroNotes Editors: Gordon Webster & Douglas Fleming (email@example.com)