President’s Report – February 2018

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I find it fascinating that we have developed a sensationalized vocabulary about naturally occurring events. Perhaps it is the result of reality television becoming so prevalent that everything must be a challenge, a contest, the best, the brightest, the most shocking, etc. Having the recent lunar eclipse labelled with 3 different descriptors, super moon, blue moon, and blood moon, made for some interesting headlines. Are these events really deserving of these labels?

The distance between the moon and the earth does change throughout the month due to the moon’s elliptical orbit. For a viewer on earth, the apparent change in the moon’s diameter between apogee and perigee is about 13%. That does make a full moon around the perigee appear larger thus potentially brighter. But do most of us really notice without being told? Probably not. As the earth has a greatly varying atmosphere, which has a significant influence on light transmission, the amount of light from a full moon is not a reliable indicator. How many of us can recognize that a full moon is larger, or smaller, than the previous time we saw it? Photographs will show a difference but most of us do not have that sort of visual memory. Is a moon that appears to be 13% larger than at its smallest apparent diameter a difference worthy of being called a super moon? I lean toward describing it as a full moon near the perigee.

According to sources I have found, the term blue moon, when used to count full moons in a certain time period, was originally used for seasons. Most seasons have three full moons but every tenth season or so has a fourth full moon. The blue moon was the label given to the third full moon of a season with four full moons. Along the way, blue moon has become an accepted expression for the second full moon in a single calendar month. Is having an extra full moon in a month or a season, both of which are arbitrary, human-designated periods of time, significant? Why not just refer to it as the second full moon of January? By the way, March 2018 also has 2 full moons so we will have a second blue moon this year.

The term blood moon is used to describe the red-coloured moon that we see during a lunar eclipse. During the eclipse, the sun’s light is blocked from reaching the moon’s surface directly. The earth’s atmosphere scatters light, particularly in the blue-violet end of the spectrum. This means that light that has passed through the earth’s atmosphere and travels on toward the moon is primarily at the red end of the spectrum. Some of this light will end up reaching the moon’s surface and the result is a moon illuminated by light that is strongly in the red wavelengths. I’m not sure why we just don’t call it a red moon.

So, although we did not see much of the eclipse here, I hope those who did enjoyed seeing the large, red moon caused by the lunar eclipse during the second full moon of January 2018 when the moon was close to perigee. Ok, maybe saying the super blue blood moon sounds better!

Total Lunar Eclipse – Jan 31, 2018

Posted by as Observing Highlights

Total Lunar Eclipse on Sep 27, 2015 from Victoria
Total Lunar Eclipse on Sep 27, 2015 from Victoria – photo by Joe Carr

On Wednesday, January 31st, weather willing, we will be able to view a total eclipse of the Moon. The Moon will move into full eclipse in the early hours of the morning and will be in partial phase in the western sky as the Sun rises. The Total Lunar Eclipse will develop over the course of about 3 hours. It’s a perfect opportunity to capture some snapshots of the event. Read further to find out what happens during the eclipse and how to capture it photographically.

 

 E C L I P S E   T I M E L I N E
Moon below the horizon Moon’s eastern limb enters the penumbra 2:51 am PST
Partial eclipse begins – 1st Contact Moon’s eastern limb enters the umbra 3:48 am PST
Total eclipse starts – 2nd Contact Moon entirely in the umbra;
deep orange red
4:52 am PST
Totality 5:30 am PST
Total eclipse ends – 3rd Contact 6:08 am PST
Partial eclipse ends – 4th Contact Moon’s western limb leaves the umbra 7:11 am PST
Sunrise 7:48 am PST – approximate
Eclipse ends Moon leaves the penumbra 8:09 am PST

 

What’s Happening

A total lunar eclipse occurs when the Earth comes between the Sun and the Moon. During a lunar eclipse the Moon’s position traverses the Earth’s shadow. The Moon’s first contact with the Earth’s shadow is at the outer band of the shadow called the penumbra. The light falling on the Moon is progressively blocked until at the moment of total eclipse the Moon is completely in the darkest central area of the Earth’s shadow called the umbra. At the point of total eclipse the process starts to reverse itself until the Moon is totally out of the Earth’s shadow.


Glossary

  • limb – the outer edge of the Moon
  • penumbra – the outer band of the Earth’s shadow
  • umbra – the darker central area of the Earth’s shadow
  • partial eclipse – the Moon is positioned within the penumbra
  • total eclipse – the Moon is positioned totally within the umbra
Above Eclipse times are for Pacific Standard Time (PST) for the west coast of North America, and are calculated from UT as presented in the Observers Handbook 2018, pages 126-27.

Observing Tips

What do you need?

Everything from your eyes, binoculars and telescope are suitable. Bear in mind this is a long process and at this time of year dress warmly and bring a chair if you want to be comfortable.

Find yourself a location that has a clear horizon view of the west especially if you wish to view during the late stages.

Keep a log of what you see and note the time. Pay attention to how much of the light on the moon is obscured and if there are any colouration changes. During the total eclipse the Moon will take on a deep orange-red colour. The colour of the Moon is a function of contaminants in the atmosphere and varies from year to year.


Photographic Tips

Equipment
Any camera with the capability of setting shutter speeds and aperture settings manually will do fine. The ability to use interchangeable lenses will be an advantage for more detailed images of the Moon. For the darker parts of the eclipse, eg. totality you should use a tripod support for best results. If you have access to a telescope you can try capturing the event using prime focus techniques through the telescope optics.

Settings
Today’s digital cameras are very sensitive to light reflected by the Moon. Use ISO 400 to ISO 800 and a long telephoto lens or zoom setting. Smartphones and point-and-shoot digital cameras will not produce rewarding photos of the eclipsed Moon, but can be useful for taking panoramic shots of your surroundings which include the eclipsed Moon.

Technique
The simplest eclipse pictures can be taken with manual settings on your camera and a normal lens, preferably supported by a tripod. For best results use a cable release to minimize vibration. Images taken in this fashion result in a small lunar image. This is why it is preferable to use a telephoto lens to photograph the Moon. For a 35mm camera try a 200mm lens or something close to this, even better a 500mm lens or higher. You may also use teleconvertors to increase magnification, these typically come in 1.4x and 2x strengths. Their downside is they reduce the effective aperture of your optical system. A 1.4x teleconvertor will decrease your effective exposure by 1 stop, a 2x teleconvertor will decrease your effective exposure by 2 stops. Work out your effective aperture of your optical system ahead of time so you don’t have to think about it on the night of the eclipse.

Example:

 

 Focal Length  Aperture Effective Focal Length
with 2x teleconvertor
Effective Aperture
with 2x teleconvertor
 180mm  2.8  360mm  5.6
 480mm  6.8  960mm  13.6

 

To achieve any higher magnification than what is stated above you will have to use a telescope at prime focus. For this your manual camera does need to have the capability of using interchangeable lenses. For prime focus you will use the telescope optics as your interchangeable lens. To attach your camera to your telescope you will need two things a T-adapter that fits your camera and a telescope camera adapter that fits your telescope. The telescope camera adapter is designed to fit in the focusing tube of your telescope and is threaded to accept the T-adapter of your camera. With the magnification involved with telescopic optics it is likely that you will need to use a tracking mount. Preferably the mount should be able to track at lunar speed as opposed to sidereal but if the shutter speeds chosen are shorter than 1 or 2 minutes this is not critical.

Exposure times are the next consideration. The following exposure times are based on a medium speed film and an effective aperture that would be common with a long telephoto and teleconverter combination. Exposures may vary with your equipment based on ISO speed of film used and effective aperture. The Danjon Lunar Eclipse Luminosity Scale has been included to provide better guesstimates for totality.

 

Exposure Times: based on ISO 400
Full Moon  1/250 second at f/16
1st Contact 1/125 second at f/16 see note 1.
2nd Contact 2 seconds at f/16 see note 2.
Totality
*see table below
L = 4 : 8 seconds at f16
L = 3: 30 seconds at f16
L = 2: 2 minutes at f16
L = 1: 8 minutes at f16
3rd Contact 2 seconds at f/16 see note 2.
4th Contact 1/125 second at f/16 see note 1.
* Danjon Lunar Eclipse Luminosity Scale
 L = 1 dark eclipse; lunar surface details distinguishable only with difficultly
 L = 2 deep red or rust coloured eclipse; central part of the umbra dark but outer rim relatively bright
 L = 3 brick-red eclipse; usually with a brighter (frequently yellow) rim to the umbra
 L = 4 very bright copper-red or orange eclipse, with a bluish, very bright umbral rim

 

Note 1. 1st and 4th contact times given for the partial phases are biased for the light part of the Moon. Remember you are dealing with vastly different exposures between the light and dark parts of the Moon during eclipse. The bias of about 1 stop minus avoids overexposure of the dominant bright area of the Moon.

Note 2. 2nd and 3rd contact times given for the partial phases are biased for the dark part of the Moon. The bias of about 1 stop plus is a good strategy for negative film not quite so good for slides and digital capture given they don’t tolerate overexposure well.

The exposure times are only recommendations. Remember the cardinal rule about photography … bracket. Always try exposures plus and minus your chosen exposure. This gives you a better chance at getting usable results. Let’s all hope for clear weather. If you have any questions please send email to David Lee at davidflee7331@gmail.com.


David Lee – original image and text
Joe Carr – updated for 2018
Brenda Stuart – illustrations

President’s Message – January 2018

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Happy New Year!

As a follow-up to last January’s report, it is time to report back about my progress with my astronomy resolutions of 2017. One of my goals was to learn more and I did achieve that. One area I know little about is astrophotography. To learn more, I purchased a CCD camera in March and have been learning to use it. Primarily, I have done this in daylight hours so I could see what I was doing. I have tried photographing distant objects, typically trees, so I can work on achieving focus. I chose a monochrome camera so I also bought a set of filters and a filter wheel so I have been figuring out how to include those in what I have been doing. As there are a number of parts to all this, i.e., camera, filter wheel, software, etc. there is a lot to learn. I have taken small steps so far but I am getting much more proficient at the tasks I have practised.

Another goal was to spend more time observing. I did spend more time looking through a telescope in 2017 which was good and I’m getting much better at finding objects. One thing to work on this year is getting out on more evenings when the sky is clear. It is still too easy to turn on the television or sit in front of the computer. So this year, my goals are to keep learning and do even more observing.

2018 is looking to be another active year for the Victoria Centre. As introduced in my December report, the first event of 2018 will be the launch of the RASC sesquicentennial on Saturday, January 27. We will be looking for helpers for this event in the coming weeks and I hope that many of you can attend.

We are planning to hold Astronomy Day in April again this year as well as Summer Star Parties at the DAO. These are great opportunities to get involved and more information will be provided as plans are made. Make sure you visit our website to keep up to date about the activities of our Centre.

Lunar “X” during 2018

Posted by as Observing Highlights

Lunar X feature - photo by Michel Michaud
Lunar X feature – photo by Michel Michaud

by Michel Michaud, RASC Victoria Centre Observing Co-chair & Librarian

The Lunar X is a claire-obscure effect in which light and shadow creates the appearance of a letter “X” on the rim of the Blanchinus, La Caille and Purbach craters. The X is visible only for a few hours before the first quarter slightly below the lunar terminator. Near the X, the lunar V is also visible, formed by Ukert crater and several other small craters.

If you never had the chance to view the Lunar X, also known as the Werner X, there are several time this year that feature could be visible from Victoria. The time predict the beginning of the event and all in LOCAL TIME.

  • 23 January 2018, 2042 (8:42 pm) – Tuesday evening event
  • 23 March 2018, 2357 (11:57 pm) – Friday evening event
  • 21 May 2018, 0002 (12:02 am) – Monday evening event
  • 19 July 2018, 2314 (11:14 pm) – Thursday evening event
  • 16 September 2018, 2332 (11:32 pm) – Sunday evening event
  • 14 November 2018, 0059 (12:59 am) – Wednesday evening event

Werner “X” observation – 2014

President’s Message – December 2017

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With 2018 on the horizon, we have two events to celebrate in the New Year.

The first is the sesquicentennial of the Royal Astronomical Society of Canada. RASC commissioned a history of the society, Looking Up: A History of the Royal Astronomical Society of Canada that was written by R. Peter Broughton and published in 1994. It is available on the RASC website at rasc.ca/looking for those who would like to know more about the history of our society.

The society traces its roots to the year after confederation when a group of friends formed the Toronto Astronomical Club in 1868. The club was renamed as a society in 1869. Around 1884, the name of the society was changed to The Astronomical and Physical Society of Toronto; the society was formally incorporated in Ontario in 1890. In 1900, the name reverted to the 1869 version, namely, The Toronto Astronomical Society. Two factors resulted in this name only being used for three more years. The first was that astronomical clubs were forming in other Canadian cities and a number of clubs elsewhere in Ontario had affiliated with the Toronto society. It was realized that having Toronto in the name was too restrictive. The second was the 1901 visit of the Duke and Duchess of York, later to become King George V and Queen Mary. Their visit increased interest in the monarchy and led to the suggestion that the society become a royal society. After much debate, the society decided to petition King Edward VII for The Toronto Astronomical Society to become the Royal Astronomical Society of Canada. The formal request to change the name of the society was granted on March 3, 1903.

Additional centres formed over the years with our own centre being founded in 1914. If you look at the centre list, that does make us one of the original six! Much has happened in the 150 years since a group of friends with an interest in astronomy decided to form a club. A wonderful logo has been created to help celebrate this anniversary drawing on highlights of Canadian astronomy. Make sure you have a look at the RASC sesquicentennial site, rasc.ca/2018, to learn more.

There will be a number of celebrations during 2018 in honour of this anniversary. The first will be held on Saturday, January 27. The RASC 2018 committee is proposing a cross-country Star Party that will combine solar and lunar observing (weather permitting), starting on the Atlantic coast and reaching westward and northward to encompass all Centres as the afternoon progresses. The logistics of the local Star Party will be at each Centre’s discretion but the committee proposes a start time of 3 p.m. local time. Technology permitting, the Star Parties will be linked via Google Hangouts and the link will be shared publicly allowing anyone to witness the sun, moon, and the local celebrations. We are looking at holding our event at the University of Victoria as that would provide us with the technological support and space needed. More details will be announced as they become available.

The second anniversary of note is the centennial of the Dominion Astrophysical Observatory. It was announced in 1914 that the observatory would be built on Little Saanich Mountain but it would take 4 years for the observatory to see first light on May 6, 1918. There are plans underway to celebrate this historic anniversary and further details will be shared as they become available.

On behalf of the Council of the Victoria Centre, I wish each of you a happy holiday season and all the best for 2018!

 

 

President’s Message – November 2017

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Another Victoria Centre milestone was reached in the past month with the installation of our new 16″ Ritchey-Chrétien telescope at the Victoria Centre Observatory. So far, it is exceeding our high expectations and my initial impression is it was the right choice.

I was part of the group of active observers who met on the hill on Saturday, October 28 for its first light at a VCO evening. We had a look at a number of targets with varying magnifications and the views were impressive. A number of the group, including Charles Banville, Joe Carr, Bruce Lane, and John McDonald, took photographs through the telescope which turned out very well. Some of these were shared at Astro Café on Monday, October 30 and a number are posted to our Zenfolio site. The moon was in the waxing gibbous phase and proved to be a great subject for photography. A couple of the Messier objects, M13 and M57, were photographed as was Uranus. As there were so many members at the VCO, the photographers were taking fewer exposures than normal to give everyone a chance to use the telescope. The quality of the results from last week show the great potential for our new telescope. Just imagine the detail that will be captured with even more photographs being stacked into a single image!

As a new member on one of my first visits to the VCO, I remember being told that the 14″ Meade was a temporary scope. I wondered a bit about that as the 14″ is an impressive telescope. It has a large primary mirror which reaches far into the dim night sky. How could that be surpassed except by an even larger telescope? As I have learned more, I can see why the telescope design matters as well. A Schmidt-Cassegrain, like the 14″ Meade, is a good telescope and served us very well. However, a Ritchey-Chrétien telescope is an even better choice for an observatory such as ours. The advantage of a larger field without optical distortion is why most of the large, professional telescopes favour this design. Our 16″ does not match the professional scopes in size but it does provide us with the same optical design.

A heartfelt thank you goes to the our technical committee for their efforts to research and choose this telescope. I look forward to using our new telescope on future visits to the VCO!

President’s Message – October 2017

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Another season of Summer Star Parties at the DAO has come to an end. We had more evenings this year with a star party most Saturday evenings from the end of April through late September. We will be meeting with our partners, the Friends of the Dominion Astrophysical Observatory, to review this season and start planning for next year. As always, I am interested in hearing feedback, ideas, and suggestions. Please send me your ideas at president@victoria.rasc.ca.

For me, the highlight of the star parties are the many conversations I have with our visitors. Every evening there were great conversations about what we were seeing, the night sky, travel, life in the universe, etc. There were many gasps of amazement especially when we were looking at Saturn. Saturn really is a highlight of the night sky; it was the first object I recall seeing through a telescope when I was in high school. I still enjoy looking at it all these year later!

Many of the visitors were amazed to learn the telescopes they were looking through are personally owned. So many said how much they appreciated the opportunity to see the night sky and our generosity. The time we donated to the star parties was greatly appreciated and I, too, thank all the members who were involved this year.

Next year, we have two major anniversaries. The first is the centenary of first light of the Plaskett Telescope. Already a National Historic Site of Canada, there are some events being planned in order to celebrate. One of the ideas being considered is submitting an application to have a float in the Victoria Day Parade. We are looking for a couple of centre members who would be interested in helping with the design, planning, and execution of a float. Please let me know if you would like to join the parade committee. The second anniversary is the sesquicentenary of RASC. There will be some celebratory events happening in honour of this anniversary.

Save the date: Shortly, I will be sending out information about the November AGM including pre-ordering your entree. The entree choices are salmon, chicken, vegetarian ravioli, or steak. The AGM will be held on the evening of Saturday, November 18 at the Cedar Hill Golf Course. Doors will open at 6 p.m.

President’s Message – September 2017

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The summer of 2017 will be noted for a relatively rare event, a solar eclipse visible across North America. Many Victoria Centre members travelled to see totality including me. That was my first total eclipse and it was an extraordinary experience. I now understand why many members of the club make it a priority to view total solar eclipses. The totality was all too short but even that 2 minute experience made the trip worthwhile.

I viewed the eclipse at the home of friends in western Idaho; in all, 22 of us set up to watch the eclipse. We put chairs in front of their garage as that faces east and got ready for the eclipse to begin. With the garage door open, we had a shaded space where we could get out of the sun’s heat as needed. As the eclipse progressed, we noticed that we did not need that shade as the sun’s rays no longer felt hot. That happened some time before the amount of light was reduced so it was an interesting sensation.

We looked around for objects projecting the sun and it was great to see the effect of the spaces between leaves as the sun became an increasingly narrow crescent. We had my solar telescopes set up to provide a view of the sunspots and prominences. I noticed that the progress of the eclipse was more evident with the magnification of the telescope than though eclipse glasses. We also put out a white sheet to see if we could see the shadow bands. We did see them at both ends of totality.

Totality was amazing. Having that all too brief diamond ring and then the sudden appearance of the sun’s corona was magical. I had a good look to see if I could see some of the stars but I only saw Venus. As the seconds ticket by, we knew it would soon be over, but did our best to enjoy the spectacle. Sure enough, another diamond ring appeared and the light started coming back. It was a letdown that it was over but the experience is not to be forgotten.

Now we are back into the “regular” time of the year monthly meetings resume on Wednesday, September 13  at 7:30 p.m. in room A104 in the Bob Wright Centre at UVic. Astro Café resumes at 7:30 p.m. on Monday, September 11 in a temporary location while our regular room is renovated. We will be posting the schedule of other events as they are completed. As a reminder, the November meeting is our AGM. That will be held on the evening of Saturday, November 18 at the Cedar Hill Golf Course. Please keep an eye on the website for details about upcoming events.

Press Release: RASC Victoria – August 21 Eclipse Viewing

Posted by as Observing Highlights, Special Events

RASC VICTORIA CENTRE ANNOUNCES AUGUST 21 ECLIPSE VIEWING IN VICTORIA

Viewing planned for Royal BC Museum, Mount Tolmie & Metchosin Cricket Pitch

Members of the Victoria Centre of the Royal Astronomical Society of Canada will be setting up their solar telescopes in three locations around Greater Victoria for public viewing of the solar eclipse on the morning of Monday August 21.

Because looking directly at the Sun at any time is dangerous without proper protection, the telescopes at these events will be equipped with shielding to allow members of the public to safely see the eclipse. While the eclipse will be total in some parts of the United States, the eclipse in Victoria will be only a partial eclipse, where parts of the Sun will always be visible. The August 21 eclipse in Victoria will begin at 9:08 a.m. and end at 11:38 a.m. At 10:20 a.m., the Moon will block around 90 percent of the Sun as seen from Victoria.

RASC members will be setting up their telescopes during the eclipse on the morning of August 21 in front of the Bell Tower at the Royal B.C. Museum at 675 Belleville Street in Victoria, at the Cricket Pitch in Metchosin behind the Fire Hall at 4400 Happy Valley Road, and at Mount Tolmie Park off Cedar Hill X Road in Saanich, which can be reached by going up Mayfair Drive to the top of the Mountain, where telescopes will be located on the water reservoir facing south.

The University of Victoria will hold an open house for eclipse viewing that morning open to the public at the UVic Observatory on the fifth floor of the Bob Wright Building.

There will be no public eclipse viewing at the Dominion Astrophysical Observatory.

For more information on the Victoria Centre of the RASC, please go to our website at https://www.victoria.rasc.ca
For UVic eclipse information, see http://www.uvic.ca/science/physics/about/home/news/current/solar-eclipse.php

-30-

Contact person: Ken Mallory outreach@victoria.rasc.ca 250-598-8628