President’s Message – Nov 2021

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Everybody should have a good astro-project on the go. My current one concerns the timing of lunar eclipses.

Solar eclipse geography and timing is known with remarkable precision. So much so that people, including many members of our RASC community, are willing to plan long, difficult, and expensive trips to watch them. The timing and location of the earth’s shadow, or umbra, across the Moon during a lunar eclipse is much more variable and poorly understood.

I was delighted to learn that as far back as 1687, Philippe de la Hire published that the Earth’s shadow was larger than could be accounted for by an airless Earth, leading to lunar eclipses that start a few minutes earlier and end a few minutes later than expected. This was important work, because observing the timing of eclipses was, in principle, one way to measure longitude – as long as the expected timing was well established.

Moon on Dallas Road, Oct 8, 2021, by Randy Enkin

The problem arises from the complex nature of the earth’s atmosphere that obscures, diffracts and refracts the sun’s light on its way to the Moon. I first became aware of the role of amateur lunar crater eclipse timing just before the eclipse last May (which was clouded out), and I am certainly keen to try again on the upcoming lunar eclipse, starting around 23:19 PST on Thursday, November 18. If there are clear skies, I’ll be out with my telescope, noting the time to the tenth of a minute that the earth’s umbra darkens (“immersion”) and then departs (“emersion”) from various lunar craters. Sky and Telescope has been compiling these observations since 1956. Herald and Sinnott (2014) have analysed the compilation, extended back to 1842, with an amazing 22 539 observations. Their main conclusion is that the Earth is surrounded by a “notional eclipse-forming layer” that is 87km thick. It is a really surprising result, since even noctilucent clouds don’t show up that high in the atmosphere.

Herald and Sinnott point out that amateur uninstrumented observations provide continuity with the early observations in their compilation and provide insight into the visual response of the human eye. To help with the observations, Thursday- Friday November 18-19, I have annotated a picture of the full moon with the crater timings predicted by Fred Espenak. I hope some of you will join me making these simple but useful observations.

Look Up,
Randy Enkin, President@Victoria.RASC.ca

President’s Message – October 2021

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Questions, Answers, and Questions

Randy Enkin using his sextant
Randy Enkin using his sextant

One satisfaction of astronomy is the sense of continuity with astronomers from all over the world and spanning the decades, centuries, and millennia. The wonders of the sky fill us with awe and provoke so many questions. I appreciate the multidisciplinary approach to answering these questions.

Today’s anecdote concerns an article published this week, with 25 authors from 5 countries. The Chinese Chang’e 5 probe brought back to Earth the first lunar samples in 4 decades. They targeted a place on the Moon that was suspected of being young, due to the region’s low density of craters. Galileo observed craters on the moon 400 years ago, but it was only in the 1960s that meteor impacts were confirmed to be the dominant mechanism of their origin.

The observational and theoretical development of celestial mechanics, universal gravitation, the solar nebula, and planetary accretion were all required to understand dating planetary surfaces, by measuring the size and number of craters. We also needed telescopes, rockets, robotics, petrology, geochemistry, and geochronology to complement the study. The Moon is the only planetary body where impact crater ages have been calibrated with radiometric dating, but there had been no samples so far measured that are between 3.2 and 0.8 billion years old. The new samples were dated at 1.96±.06 billion years, sitting in the middle of that gap and forcing a revision of the current crater dating method. The new date is very young for the Moon’s surface and brings up new questions, like why the Moon was still melting crust so recently.

Back-scattered electron (BSE) images and false color energy dispersive spectroscopy (EDS) element maps of the two fragments from the Chang’e 5 sample
Back-scattered electron (BSE) images and false color energy dispersive spectroscopy (EDS) element maps of the two fragments from the Chang’e 5 sample

I’m filled with a sense of connection with my fellow humans who can conceive of such questions, work on them from many different aspects over the centuries, answer some, and end up with even more questions. And I look up at the sky with happiness.

Look Up,
Randy Enkin email

President’s Message – September 2021

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Carolyn Shoemaker
Carolyn Shoemaker (Nature)

Carolyn Shoemaker died last month. After her children had grown up and she was 51 years old, she started her astronomy career. She helped establish the Palomar Asteroid and Comet Survey, and for decades she studied the photographic plates coming off of the 18 inch Schmidt wide-field telescope, located in a dome next to the Palomar 200 inch telescope. At an average of 1 discovery for every 100 hours spent at the stereoscopic microscope, she became the world’s top comet finder.

This was more than a job. Everybody who knew her emphasizes her enthusiasm and humour. Among these friends is an acquaintance of several of our centre members, David Levy. On March 23, 1993, David passed some photographs he had just taken of the region near Jupiter, and Carolyn exclaimed that she saw in these images a strange “squashed” comet. This comet became known as Shoemaker-Levy-9. It was actually the 11th comet they had discovered together, but two were aperiodic and so had a different naming convention. I remember the excitement, when 4 months later, 21 fragments of SL9 crashed into Jupiter with images from professionals and amateurs alike started pouring in. We got to watch a cosmic collision in real time!

What kept Carolyn Shoemaker at this slow, painstaking task was similar to what many amateur astronomers feel. She said “The thrill of discovery is deeply satisfying”. Few of us will get the opportunity to do cutting edge science with the best instruments available, but all of us get our own personal thrills. Whether the discovery is at the eyepiece, or on the computer monitor, or from a revelation that comes during a talk at our Astro Cafe, the experience continues to be deeply satisfying. In memory of Carolyn Shoemaker, I wish you all many more of these deeply satisfying moments!

Look Up,
Randy Enkin, President email

President’s Message – August 2021

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I’ve had a couple of requests this summer to help friends who have never seen Saturn through a telescope with their own eyes before. One of them was lent the wonderful 1970s Tasco 60mm refractor that I bought off Reg Dunkley, at our Astro Cafe exchange, way back when we could meet in person. Reg says this telescope kindled his interest in astronomy years ago, so it is fun to give this equipment to another enthusiastic newbie. The other request is from Toronto and I’m getting a RASC Toronto Centre loaner scope ready, for when I’m there next week. We do indeed belong to a great society that gives us these opportunities.

Saturn – by Brock Johnston

But what is it about seeing the beautiful objects in the sky ourselves? There are much better images available on the internet. Nothing we can see from Earth compares to the pictures of our sixth planet sent by the Voyager and Cassini spacecraft. Saturn especially has been something that has turned on people from all walks of life to the delights of the night sky. Indeed, the design specifications for the “Galileo-scope” included the possibility to see the rings of Saturn, because they knew that that view is the gateway to spending more time with a telescope (I have one, and it works!).

Saturn is certainly other- worldly. It is beautiful in its form and symmetry. The physics which produce the rings are non-intuitive. It is a challenge to see it, but not an unreasonable challenge for most. But there must be more.

Each time I take my telescope out, I fall in love again with the universe we live in. Even when I am alone, I sometimes swoon out loud. I don’t know why, but I sure am glad I get to share the feeling with my astro-friends. As our friend Diane Bell told us: “the sky is a gift!”

Enjoy the sky. Share it.
Look Up,
Randy Enkin, President email

President’s Message – July 2021

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Do we ever get tired of the view?

I recently picked up my niece from the airport. When we got our first sight of the Olympic Mountains towering over the Juan de Fuca Strait, she asked if people in Victoria ever get tired of the view. I don’t think so.

Similarly, I observe that amateur astronomers just don’t get tired of looking up. The beauty takes our breath away. There is a joy in learning the constellations and getting competent at star hopping. There is the awe in learning more about the processes that produce the spots and fuzz-balls in the night sky. I never tire of improving my knowledge of the craters and mountains on the Moon, but often I just wander about the Moon in my eyepiece, appreciating the view. We keep improving our equipment, trying to see that little bit of extra detail. Why? For the joy and sense of accomplishment.

At the Astro Cafe this week, we hosted two distinguished selenologists. Gary Varney, from Florida, is a renowned lunar astrophotographer who waxed eloquent about the details he loves to watch at the terminator – the line that separates day from night on the Moon. Brian Day, from California, leads a program at NASA that presents map and data portals, available for free on the Internet, of the planets and moons. Brian told us that he enjoys ending his day by flying around over the Moon with Moon Trek, enjoying the view and trying to figure out how features were formed.

We had dinner guests this week, and I got to show them the young (27 hour old) moon through the 8 inch Dob I’m borrowing from the club (Nelson Walker’s old telescope). One guest had never seen the craters on the moon and got wonderfully excited. Do I ever get tired of the view? Not at all. It feels as fresh and exciting as when I first saw the craters when I was 8 years old.

Look Up,
Randy Enkin, President@Victoria.RASC.ca

President’s Message – June 2021

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In praise of our Astro Cafe

Members attending Astronomy Cafe using Zoom

Every Monday evening at 19:30, the Victoria Centre runs the Astro Cafe on Zoom. I look forward to it every week! Much of our time as amateur astronomers is spent alone and I suspect that is considered a feature of this hobby by many. But we also like to share our accomplishments and problems. While we are isolated by the pandemic, Astro Cafe brings our community together.

I had been a regular contributor since I joined the Victoria Centre three years ago. Now that you have made me president, I feel that part of the job is to think of something to contribute each week. I try to riff off of some recent astronomical event, for example the summer solstice for our June 21 Astro Cafe. I am particularly excited about linking current astronomical work to the centuries and millennia of astronomers from the past, who figured out so much of how our universe works without the advantage of all the recent technologies and research.

The Astro Cafe also helps us advertise events and opportunities. It provides our members a forum to present their recent, or not so recent, work. I particularly enjoy the discussions, as we learn from each other. We have such a wide variety of specialties and levels of expertise to learn from. Our community is refreshingly supportive and non-judgemental. Everybody should consider making a presentation. If you read something that you found interesting, share it! If you feel proud of an observation, sketch, or photo, share it! If you have an astronomy question, ask it!

Special thanks go out to Chris Purse who masterfully organizes and leads the discussion each week, and to Joe Carr who curates the Astro Cafe videos onto Youtube.

Look Up,
Randy Enkin email

President’s Message – May 2021

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Part of the fun of amateur astronomy is getting caught up in “rabbit holes”. You see something on Facebook, that gets you looking up articles in the popular press, and then into academic publications, and they lead you in a different direction and everything is so fascinating and time just rushes by…

The Moon aligned with Ogden Point breakwater - Randy Enkin photo
The Moon aligned with Ogden Point breakwater – Randy Enkin photo

My current example is looking into the timing of craters on the moon – when they enter and exit the umbra or full shade of the Earth. It was an important way to figure out the time, and therefore one’s longitude, before reliable clocks were made. In the 18th century, astronomers recognized that there is a problem (La Hire, Tabulae Astronomicae, Paris 1707); the earth’s shadow is over 100 km bigger than expected. The anomaly is bigger than can be explained easily with the atmosphere. One would think this is a simple geometric problem that is fully understood, but it is still under study!

Amateur astronomers are helping collect the necessary data. Sky and Telescope publishes predicted times for when the shadow is expected to cross 24 prominent craters, and they request people to email in their observed times. Upcoming May 26, 2021, eclipse online info. Up to 2011, their database includes 22,539 observations by 764 different people. If the sky is clear between 02:52 and 05:48 on Wednesday May 26, I hope to add my name to the list!

The point is, we are a community of interesting and interested people. We set challenges for ourselves. Some are simple; some are very difficult. Get your telescope to track better. Process an image to show more detail. Understand black holes a bit more. Learn another myth of a constellation. And then we get together (virtually, these days) and support each other in these pursuits.

President’s Message – April 2021

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I love the variety of categories in the Amateur Astronomy community. Most of us will be interested in several and passionate in a few. I’m just listing the following from the top of my head and I would appreciate your input.

Randy Enkin using a sextant

We can categorize by equipment: naked eye, binocular, wide-field camera, telescopes, and a few who adventure outside visible light to study radio waves. Telescopes range in aperture, focal length, geometry, optical quality; plus mount style, motors, and automation.

How about by target: the constellations, the sun, the moon, the planets, binary stars, and the deep space objects – nebulas, clusters, and galaxies. There are also the ephemera: meteors, auroras, and the occasional comets. There are also the more predictable events such as eclipses, conjunctions, and occultations.

Some people simply observe, while others record notes, sketch, or photograph. Astrophotography has quite a range, from single shot, to stacking, to long exposures with specific filters.

There are some specific studies, such as variable star photometry, spectrography, or plotting annual parallax. My 31-year- long time series of lunar phases and my recent addition of measuring changes in the lunar diameter would fit here.

And then there are the arm-chair categories – too many to be exhaustive: studies in stellar evolution, planetary evolution, exoplanets and exobiology, galactic evolution, astronomy across the entire electromagnetic spectrum and now gravity waves, black holes, and cosmology. Space travel and technology is a huge category on its own. I have a particular interest in the history of astronomy – how we got to understand things so distant and complex with simpler equipment and theory.

I know members of our community interested in every single one of these categories! And it makes me rejoice that we are together at all our different levels and complementary interests and skills.

Look Up,

Randy Enkin Email

President’s Message – March 2021

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The RASC Victoria Centre welcomed me 3 years ago. I was asked to give a talk about my moon observations at the Astrocafe, and then I became a regular. Now you have given me the opportunity and challenge to be this community’s president.

Ten-year-old Randy projecting the solar eclipse in Hamilton, Ontario, 1970-07-10. (Photo credit, Eleanor Enkin)
Ten-year-old Randy projecting the solar eclipse in Hamilton, Ontario, 1970-07-10. (Photo credit, Eleanor Enkin)

Astronomy has been a big part of my life since I was 8 years old, when Apollo 11 landed on the moon. While my friends wanted to become astronauts, my attention was on the people on the ground who were so enthusiastic about the science, and I decided I would become an astronomer. The path one walks in life is seldom a straight line, and mine brought me to earth science. I am a research scientist at the Geological Survey of Canada, studying the physical properties of rocks and sediments. But I have always dabbled in astronomy.

Fifty-six-year-old Randy projecting the solar eclipse in Victoria B.C., 2017-08-21. (Photo credit, Randy Enkin)
Fifty-six-year-old Randy projecting the solar eclipse in Victoria B.C., 2017-08-21. (Photo credit, Randy Enkin)

I have learned during the last three years that the amateur astronomy community comprises people with a wide range of interests, skills, and levels, but with a common passion to enjoy and share the sky. I have been involved with many volunteer organizations, and my impression is that the RASC Victoria Centre has an extremely high level of volunteerism and mutual support. During my tenure as president, I hope to help nurture this spirit, and support our ongoing inreach and outreach efforts within the broader Victoria Astronomy community. I look forward to getting to know more of you and learn what aspects of astronomy bring you joy and fulfilment.

It is fun to see the various ways astronomy-buffs sign off their letters. “Clear Skies” is wonderful. My predecessor liked “Usable Skies”. My sign-off comes from a note my sister has posted over her computer to remind her to get away from it as often as possible. I like the many meanings these two words hold for us:

Look Up

Randy Enkin

President’s Message – February 2021

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Much has happened since my previous monthly message. South of the border there was an attempted insurrection, an impeachment and an inauguration of a more temperate leader. North of the border, “NOT YET IMAGINED” the much anticipated study of Hubble Space Telescope Operations authored by Victoria Centre RASCal Chris Gainor was released. Click here for a free download. The Victoria Centre also acquired a beautiful 130 mm Takahashi refractor to pair with the OGS 12.5 inch reflector at the Victoria Centre Observatory. Meanwhile the Covid Vaccine inoculation program is gaining momentum. So one can sense a tentative positive vibe and some are speaking of a “light at the end of the tunnel”. Let us hope that the light is a very faint star “light months” away and not some bright star “light years” distant.

The compelling political drama and Dr. Bonnie’s updates have hijacked our attention and robbed us of that non renewable resource called “time”. The impact of this time theft is apparent in my household as copies of Sky and Telescope and the Journal of RASC lie half read. And then there are the many quality astronomical presentations on You Tube that I never got around to watching. While the face to face outreach activities have ground to a halt astronomical discoveries continue and the recording of Zoom presentations have significantly increased the amount of information available to digest.

So we are presented with a challenge. How should we ration our dwindling amount of time and how much of that should be devoted to astronomy? This, of course, is a highly individual choice. I hope the word ‘joy” is at the heart of the decision and includes the joy experienced observing the night sky, the joy of learning new things, the joy of improving our understanding, the joy of unravelling mysteries and the joy of sharing our knowledge and enthusiasm with others. Another key word is “satisfaction” which for instance can be applied to the satisfaction derived from knowing our way around the night sky, the satisfaction of acquiring skills to photograph and sketch astronomical treasures, the satisfaction of mastering a technology and the satisfaction of understanding the theory which explains what we see or detect. And don’t forget the “energy” required to make it happen and the “curiosity” to learn more. If you think of astronomy as a giant smorgasbord, the challenge is to load our plate with nourishing ingredients while trying to minimize overindulgence.

During my term as Victoria Centre President I witnessed the diversity in the appetites displayed by RASCals as they have loaded up their plates at this smorgasbord. I have been inspired by the discipline of many who systematically work on observing lists, the dedication of some to improve their astrophotography skills and the time and energy that others devote to education and outreach. I am also very appreciative of the community of professional astronomers for sharing their knowledge and research with the Victoria Centre. It has been a joy to get to know our amazing group of RASCals better and I am thankful to so many for their cooperation and support while I have been at the helm. It has been an honour to serve and I encourage you to attend our Zoom AGM on Monday, February 22nd to select our next President and Victoria Centre Council. Let us hope that we will be able to gather in person by this time next year.

Stay Well … and oh yes

Usable Skies

Reg Dunkley