Globular clusters have long been used to test theories of stellar evolution, stellar dynamics, and galaxy formation. In recent years, these old clusters have emerged as fertile grounds to search for black holes and understand their formation. “Intermediate-mass” black holes have been proposed to lurk in their centres and could represent seeds from which super-massive black holes grow in the early universe. Dynamical formation of stellar-mass black hole binaries in the dense cores of globular clusters has also been suggested as a main formation channel for the sources of gravitational waves recently detected by the LIGO experiment. I will give an overview of the recent successes (and failures) of astronomers’ exciting hunt for black holes in globular clusters.
Bio: Vincent Hénault-Brunet recently joined NRC Herzberg as a Plaskett Fellow. He was born in Montreal, where he completed his BSc in physics from McGill and MSc in astrophysics from Université de Montréal. He then obtained his PhD from the Institute for Astronomy at the University of Edinburgh (UK), and was a research fellow at the University of Surrey (UK) and Radboud University (Netherlands) before moving to Victoria. His research focuses on stellar populations and globular clusters, in particular on the dynamics of stars in these systems.
As the spring and summer approaches, planning is underway for our annual season of outreach events. The first event of the season is Astronomy Day on Saturday, April 21 at the Royal BC Museum. We will require volunteers to help with this event including people for the information table, people to do a show and tell with telescopes and their astrophotography, and some solar viewing as well if the skies cooperate. If you have not already been contacted and wish to help out, please contact Ken (firstname.lastname@example.org) to put your name on the list as an outreach volunteer.
We will be holding another season of Star Parties at the Dominion Astrophysical Observatory on Saturday evenings. The first of these evenings will be on Astronomy Day. The season will continue until Saturday, September 1 for a total of twenty evenings. Planning is underway for some special evenings including Saturday, May 5 to coincide with the 100th anniversary of first light of the Plaskett Telescope that was on May 6, 1918. Again we will need people to be on hand to direct the visitors, provide views of the sky with telescopes, and other duties. We have a contact list of volunteers but if you are not on the list already and would like to be added please contact Chris (email@example.com).
The annual general meeting of the Canadian Astronomical Society (CASCA) is taking place in Victoria this year. The conference title is A New Century for Canadian Astrophysics and it will be at the convention centre from May 22 to 26. Through a special arrangement with the organizing committee, members of RASC may register to attend. The options for RASC members are a one day rate or four day rate; the early bird rates are in effect until April 6. Complete details about the meeting, including a list of invited, centenary, and education and public outreach speakers, an outline of the graduate student workshop program, and special events, can be found on the CASCA 2018 website. One of the speakers, former RASC president R. Peter Broughton, is the author of new book about John Stanley Plaskett founder of the Dominion Astrophysical Observatory. Entitled Northern Star J.S. Plaskett, it is now available from the RASC store.
Wednesday February 14th 2017 at 7:30 PM Room A104, Bob Wright Centre.
During the past two decades, the standard model of the cosmology ΛCDM has commonly been accepted by the astrophysical community and successfully reproduced and even predicted many observational effects. I will discuss about one of the principal components of this model: dark matter and I will describe why we need it and what are the current hypotheses of its nature.
Bio: Guillaume Thomas is a new postdoctoral NRC fellow who joined Herzberg Astronomy and Astrophysics in October. He was born in Epinal France and obtained his Master and PhD at the Strasbourg Observatory. Thomas is interested in the formation and the dynamical evolution of spiral galaxies. He is also interested in exploring alternative theories to the model ΛCDM. You can follow him on Twitter at @Thomas_gft.
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!
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
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
7:48 am PST – approximate
Moon leaves the penumbra
8:09 am PST
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.
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.
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.
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.
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.
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.
Effective Focal Length
with 2x teleconvertor
with 2x teleconvertor
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
1/250 second at f/16
1/125 second at f/16 see note 1.
2 seconds at f/16 see note 2.
*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
2 seconds at f/16 see note 2.
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 firstname.lastname@example.org.
David Lee – original image and text
Joe Carr – updated for 2018
Brenda Stuart – illustrations
RASC Victoria members used the Bob Wright Centre at the University of Victoria for a nation-wide celebration of RASC astronomy in Canada for the last 150 years, from 3-5pm on Saturday, January 27th. We will were joined by astronomy teachers and students from University of Victoria, Camosun College, and Victoria High School. Tours of the 32″ telescope and observing the Sun through solar telescopes was happening outside. Members participated in a series of Youtube “webisodes” from RASC Centres across Canada.
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.
Quasars are the brightest objects in our Universe. A quasar is a rotating disk as big as our solar system and hotter than the Sun, formed when matter spirals into a supermassive black hole at the centre of a galaxy. I will discuss these fascinating objects and how they tap the strong gravity of black holes.
Bio: Patrick Hall is an astronomer and Professor at York University. Born in California to Canadian parents, he was an undergraduate at U. C. Berkeley, a graduate student at U. Arizona, and a postdoc at U. Toronto, Princeton, and the Universidad Catolica de Chile. He divides his work time between research on quasars (and any object with a sufficiently odd spectrum), teaching astrophysics, and outreach. You can follow him on Twitter at @patrickbhall
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