Charles Messier was a French astronomer who compiled and published a list of nebulae, star clusters, and galaxies, which came to be known as the Messier objects. Messier was mainly hunting for comets but sometimes ran across objects that looked like comets but were subsequently disproven. Messier’s original list identified 103 such objects that comet hunters should “ignore” – seven additional entries have been added over the years, bringing the total to 110.
A Messier Marathon is an attempt to observe all 110 objects in a single night. The best time of year to attempt a Messier Marathon is often around a new Moon in March. This weekend, March 9th&10th, is just a few days past the new Moon and the forecast for the Lower Mainland is for mostly clear skies so it provides a nice opportunity.
But some objects in Messier’s list will not be visible from latitudes above 40° north this weekend. Alan Whitman, a BC resident, has a “cover page” article in the April edition of Sky and Telescope magazine that suggests April 4th-5th, 2019 is the perfect night for a Messier Marathon from latitudes above 49° north. Even then, observing all 110 objects may not be possible.
Many women have contributed to our knowledge of astronomy. Here is a short list of four women astronomers from different time periods that made significant contributions.
Hypatia of Alexandria – 4th Century AD
Hypatia of Alexandria is regarded as the first woman astronomer. She lived during the late 4th, early 5th centuries. She taught mathematics, physics, and astronomy, and wrote many books about these subjects – thirteen books on algebra and another eight books on geometry.
Hypatia is known to have constructed an astrolabe, an instrument used to measure the positions of the stars. She used it to calculate the positions of specific stars, and then published her data in tables in The Astronomical Canon. Sailors and astronomers used her tables for the next 1200 years.
She also edited the third book of her father’s, Commentary on the Almagest of Ptolomy. The Ptolemaic model of the universe was geocentric where the sun was thought to have revolved around the earth. In the Almagest, Ptolemy proposed a division problem for calculating the number of degrees swept out by the sun in a single day as it orbits the earth. Hypatia’s contribution is thought to be an improved method for the long division algorithms needed for such astronomical computations.
Caroline Lucretia Herschel 1750 -1848
Caroline Herschel was a German astronomer and the younger sister of the astronomer William Herschel. She is best known for the discovery of several comets, including the periodic comet 35P/Herschel–Rigollet, which bears her name.
She was the first woman to be awarded a Gold Medal of the Royal Astronomical Society and to be named an Honorary Member of the Royal Astronomical Society. The King of Prussia presented her with a Gold Medal for Science on the occasion of her 96th birthday.
She independently co-discovered the galaxy M110 – this galaxy is a companion to the Andromeda galaxy M32 and was included in a sketch of M32 by Charles Messier but Messier did not include M110 in his original list. The suggestion to assign M110 a Messier number was not made until 1967.
Cecilia Helena Payne-Gaposchkin 1900 – 1979
Cecilia Payne was a British-born American astrophysicist who proposed in her 1925 doctoral thesis that stars were composed primarily of hydrogen and helium. In analyzing spectral absorption lines, she found that silicon, carbon, and other common metals seen in the Sun’s spectrum were present in about the same relative amounts as on Earth, in agreement with the accepted belief of the time. However, she found that helium and hydrogen were vastly more abundant – by a factor of about one million for hydrogen.
The astronomer Henry Norris Russell convinced Payne to initially describe her results as “spurious” because the current scientific consensus was that the elemental composition of the Sun and the Earth were similar. In 1914, he had written:
The agreement of the solar and terrestrial lists is such as to confirm very strongly Rowland’s opinion that, if the Earth’s crust should be raised to the temperature of the Sun’s atmosphere, it would give a very similar absorption spectrum. The spectra of the Sun and other stars were similar, so it appeared that the relative abundance of elements in the universe was like that in Earth’s crust.[
A few years later, the astronomer Otto Struve described her work as “the most brilliant PhD thesis ever written in astronomy”. Russell, himself, ultimately realized she was correct and admiringly acknowledged Payne’s earlier work and discovery; but nevertheless, he is often credited for the conclusions she reached.
Jocelyn Bell Burnell 1943 –
Jocelyn Bell Burnell was awarded a $3-million Special Breakthrough Prize in Fundamental Physics in 2018. The prize committee not only acknowledges her discovery of the weird, fast-spinning stellar corpses known as pulsars but also her “lifetime of inspiring scientific leadership.” The discovery of pulsars was recognized by the award of the 1974 Nobel Prize in Physics, but despite the fact that she was the first to observe a pulsar, Bell Burnell was not one of the recipients of the prize – a point of controversy since then. But Bell Burnnell was not dismayed at the lack of recognition, saying instead
I believe it would demean Nobel Prizes if they were awarded to research students, except in very exceptional cases, and I do not believe this is one of them. Finally, I am not myself upset about it – after all, I am in good company, am I not!
In 1967, Bell Burnell was working with Anthony Hewish, an astronomer at Cambridge who wanted to find more quasars and needed a new radio telescope to do so. Bell Burnell helped build the radio telescope and after it was built, she was left as the first person to run the telescope. During the first six months, she discovered over 100 quasars but the real breakthrough first appeared on August 6, 1967. She noted an “scruff” that she later found appeared over and over again in the same part of the sky. Higher-speed recordings made in November 1967 revealed that Bell Burnell had captured a repeating string of radio pulses spaced a bit more than a second apart that were unlike anything seen before. Temporarily dubbed “Little Green Man 1” (LGM-1) the source, which is now known as PSR B1919+21,was identified after several years as a rapidly rotating neutron star.
Rotating neutron stars with regular rotational periods are called “pulsars” because the produce pulses of radio waves with a very precise intervals ranging from milliseconds to seconds. The precise periods of pulsars makes them very useful tools. They were used to indirectly confirm the existence of gravitational radiation. the first exo-planets were discovered around a pulsar, and they can rival atomic clocks in their accuracy in keeping time.
Have a look towards the south between 10 and 11pm in the next few weeks and you will see some bright stars: Castor and Pollux in Gemini are fairly high, Proycon in Canis Minor is a bit lower and Sirius is blazing closer to the horizon. To me, these “winter stars” often appear bolder and brighter than the stars in summer.
But to the east of Castor and Pollux is a sparse patch of sky where Cancer the Crab, the dimmest constellation in the night sky, is positioned.
The brightest star in Cancer beta-Canceri or Altarf, is only magnitude 3.5 so it is quite faint when viewed from a location with moderate or worse light-pollution with your naked eye. The other bright stars in Cancer are magnitude 3.9 and fainter. Nevertheless, it is worth getting out binoculars or a small telescope to observe two impressive star clusters that are hosted in Cancer.
The Beehive Cluster is also knows as the Praesepe Cluster and is designated as M65 or NCG 2632. It is one of the nearest clusters to our solar system at distance of 610 light years. It appears fairly large with an apparent diameter of about 1.1 degrees. The classic Greek astronomer Plolemy described it as a “Nebulous mass in the breast of Cancer”. It was one of the first clusters observed by Galileo through his telescope and he managed to spot about 40 stars within the cluster. There are about 50 star visible with amateur equipment but over 1000 stars have being identified as being a part of the cluster with high probability.
M67 is a more compact cluster. It is much older than M44 with an estimated age of 4 billion years vs 600 million years old for M44. The cluster was first discovered before 1779 by the German astronomer, Johann Gottfried Koehler, but then re-discovered a year later by Charles Messier who added it as the 67th object to his list of non-comets.
If you have tried astrophotography then you will know how critical and how difficult it can be to find razor-sharp focus – stars appear as point light sources and there is no detailed surfaces to help in achieving focus. A Bahtinov Mask is a simple and widely used tool that can help.
The Bahtinov Mask was invented by Russian amateur astrophotographer Pavel Bahtinov in 2005. The mask is an opaque disk with slots cut out in a specific pattern. The mask is placed in front of the telescope’s objective lens or mirror so that three diffraction spikes appear when the telescope is pointed at a bright star.
The central spike moves in relation to the other two spikes as the focus is changed. Focus is achieved when the central spike is perfectly centered between the other two spikes.
The image above show how the bright star Menkalinan in Auriga appeared when imaged using a Bahtinov mask on a Celestron EdgeHD 8 with a Nikon D5100 DSLR.
A Bahtinov mask should be the proper size to fit your telescope. I have two masks: one that fits over the dew shield of a ED100 refractor and another that fits over the corrector plate of a Celestron EdgeHD 8.
Bahtinov masks can be bought commercially or you can make one yourself – the deep-sky watch website has printable PDF plans for many common telescopes.
The UBC International Canadian Studies Centre in collaboration with Green College is presenting three lectures in the 2019 McLean Lecture Series on topics involving the Arctic and Outer Space. The three lectures will take place on the following dates:
The lectures are free and will be held in the Green College Coach House on the UBC Point Grey campus from 7:30pm- 8:30pm. Receptions will follow each lecture.
Lecture 1: The Arctic cannot fully be understood without including Outer Space, from low Earth orbit to distant stars. It is time for a paradigm shift in our view of the Arctic, so that we see it anew in 3D: centred on the North Pole but extending, thousands of kilometres across the top of the planet, several kilometres down into the Arctic Ocean, 35,000 kilometres up to geostationary orbit, and billions of kilometres beyond that to other galaxies and stars. In the first of his McLean Lectures in Canadian Studies, Michael Byers explains our 3D Arctic in terms of its geographical, cultural, technological, political and legal connections to Outer Space, and points out the implications these have for the disciplines of international relations, international law and political geography.
Lecture 2: Donald Trump announced the creation of a Space Force last summer. The US President assumes that Space will become a “war fighting domain,” and there is at least some support for his assumption. For instance, in 2007, China tested its ability to destroy operational satellites by targeting a derelict satellite with a ground-based missile, creating more than 35,000 pieces of debris larger than one centimetre, all of which pose severe threats to other satellites and spacecraft. Yet since then all countries, including China, have refrained from testing anti-satellite weapons in ways that could create more debris. There is, in fact, a remarkable amount of cooperation in Space, with the International Space Station being just the most prominent example. There is also a great deal of cooperation in the Arctic, with Russia and Western states working closely together on search and rescue, fisheries management, and scientific research. This lecture explores the reasons for such cooperation, pointing out that the Arctic and Space are both remote regions with extreme environments, both suffer from “tragedies of the commons,” and both are militarized but not substantially weaponized.
Robert J. Sawyer gave a great talk at our Paul Sykes Lecture last week that featured the relationship between science/astronomy and science fiction. Robert has written many science fiction books with astronomy themes and here is a list of six real stars that have appeared in Robert’s books. Most are visible with the naked-eye from a dark site where the limiting magnitude is 5.0 or fainter but some are only visible from the southern hemisphere.
Beta Hydri: A close double with components at magnitude 4.7 and 5.5. It barely makes it above the southern horizon when observing from Vancouver. The main component is a giant star with a mass of about 3.3 suns. It lies at a distance of 350 light-years. In Calculating God, the character Hollus, an alien whose species calls themselves the Forhilnor, is from the fictional third planet in the Beta Hydri system.
Delta Pavonis is a 3.5 magnitude star in the southern constellation Pavo (the Peacock). It is a sun-like star located 20 light-years from Earth. Spectroscopy has shown that Delta Pavonis has a higher concentration of elements heavier than helium compared to our Sun. This leads scientists to speculate that it is more likely to have a planetary system though no planets have yet been detected. The SETI Institute has identified it to be the “best SETI target” in a survey of nearby stars. The alien race called the Wreeds in Calculating God are from a planet in the Delta Pavonis system.
Another southern hemisphere star, Epsilon Indi is a magnitude 4.7 star in the constellation Indus. It is one of the least luminous stars visible to the naked eye and is only visible because it is just 12 light years away. Epsilon Indi is a triple system containing a pair of orbiting brown dwarfs that were discovered in 2003. The existence of a Jupiter-sized planet is suggested by radial velocity measurements. In Starplex, the Epsilon Indi system had one of the closest portals to “a vast network of artificial shortcuts that allowed for instantaneous journeys between star systems.”
Groombridge 1618 lies in the constellation Ursa Major. It is a 6.6 magnitude star located at a distance of 16 light years. It is an orange-red dwarf with about two-thirds the mass of the sun. Virtual beings from a planet orbiting Groombridge 1618 engineered the supernova of Betelgeuse in Calculating God.
Sigma Draconis is also know by its traditional name “Alsafi” which derives from an Arabic word meaning the tripods used by nomads for open-air-cooking. It is 19 light years away has a magnitude of 4.7. It shines with only 40% of the Sun’s luminosity despite having 90% of the Sun’s mass. In Rollback, Sarah Halifax is an astronomer who translated signals from Sigma Draconis as the first transmission received from an extraterrestrial source.
Betelgeuse marks the shoulder of the hunter in the constellation Orion. It is very bright at magnitude 0.6 and appears orange in colour. Betelgeuse is a red supergiant and is one of the largest known stars – if it was located in our solar system then its surface would extend half-way to Jupiter and engulf all the inner planets (Mercury, Venus, Earth, and Mars). Massive stars use their fuel quickly and Betelgeuse has already run out of hydrogen and is fusing helium into carbon and oxygen. Some astronomers predict that it will run out of fuel and explode as a type II supernova within the next thousand years. Such an explosion would be visible in full daylight and be brighter than the full Moon! At the end of Calculating God, Betelgeuse goes supernova. The supernova explosion occurred over 400 years before the events of the novel but the radiation is first reaching Earth at the present time due to its distance from Earth. The supernova may have been deliberately triggered by an alien intelligence.
Photons are the fundamental particle of light. Senors in our retina respond to photons emitted by distant starts when we look up at the night sky. How much light has been emitted by all the stars in the universe since its birth? The answer, as reported in the journal Science by a team of astrophysicists, is 4 x 10⁸⁴ photons as written in scientific notation – that is a 4 followed by 84 zeroes!
Our universe is old and vast. It is roughly 13.7 billion years old and is thought to contain over a billion-trillion stars – way too many to measure directly. Instead, this team of scientists used the Fermi Gamma-ray Space Telescope to indirectly measure the photon density of the universe at different time points in its history. Gamma-rays are a high-energy form of electromagnetic radiation. Starlight photons can collide with gamma-rays producing a pair of electrons and reducing the energy of the gamma-rays in the process. More collisions occur when the density of photons is high so looking at a source of gamma-rays and measuring the energy lost to photon collisions is a way to measure the photon density. Gamma-ray sources with different ages then provide the photon density at different time periods.
The team studied 739 blazars as their sources for gamma-rays. Blazars are thought to be powered by super massive black holes. The accretion of matter into the black hole shoots jets of gamma-rays perpendicular to the spin axis of the black hole. A blazar is positioned so a jet is pointed directly at the Earth. The blazars in this study ranged in distance from 200 million light-years to 11.6 billion light-years which corresponds to different ages and time-periods.
In addition to the total number of photons, the study also found that the rate of star formation rose in the first two billion years of the universe, peaked roughly 10 billion years ago, and has been declining since then.
Despite all those starlight photons, far more photons were made in the Big Bang and are now part of the so-called cosmic microwave background radiation – there are estimated to be 1089 CMB photons!
A lunar eclipse with over 60 minutes of totality will be visible from BC and most of North America on Sunday Jan 20th, 2019 – weather permitting.
RASC volunteers will be at Vancouver’s MacMillan Space Centre for a special eclipse viewing event. If the weather cooperates then the Trottier Observatory at SFU will also be open for a special Starry Nights event.
A total lunar eclipse occurs when the Sun, the Earth, and the Moon line up so that the Earth’s full (umbral) shadow falls on the moon. The moon doesn’t completely disappear but it will be cast in an eerie darkness and take on a reddish hue. The eclipse starts at 7:35 pm PST with the Moon in the south-east sky slightly more than 20° above the horizon. The mid-point of totality occurs at 9:13 pm PST and by then the Moon will have moved more towards the south and climbed to an altitude of 42°.
You can watch the the eclipse with the naked eye but binoculars make eclipse colours more vivid and give great 3D views. Lunar eclipses are easy to observe even in light-polluted city skies.
A telescope allows you to watch the eclipse encroaching on craters one after another.
If you are interested in photography then check out Alan Dyer’s fantastic article on how to photograph the lunar eclipse. I am going to try to get a shot of the eclipsed moon near the open star cluster M44 – the Beehive Cluster – in the constellation Cancer. I have been doing a bit of planning and practice to improve my chances of getting a good shot.
The Moon will be located a bit over 6° from M44 so it will be a widefield shot. I entered the data for my Nikon D5100 DSLR with a 55-200mm zoom lens at 105mm and a focal ratio of F4.5 into the SkySafari app to verify the field of view will nicely frame both the cluster and the Moon.
But what about the exposure time? Dyer notes that “the crescent Moon with Earthshine on the dark side of the Moon is a good stand-in for the eclipsed Moon.” Fortunately, there was a clear patch tonight so I took a few test images at ISO 400 to practice and get a rough idea of the exposure settings – some Earthshine is visible with a 2 second exposure but stars only start to become visible with a 5 second exposure.
Click on the 5-second exposure image to see a larger version – the star that is visible a little above and to the right of the Moon is the 4.8 magnitude star 20-Cetus and most of the stars in the Beehive cluster are much fainter with magnitudes above 6.3. So I’ll need to take images at different exposures: about 1-2 seconds to capture the eclipsed moon and 20 seconds or more to capture the faint stars in the cluster. I’ll try using HDR techniques (high dynamic range) to combine the several exposures into a single image – either using the D5100’s builtin HDR setting when taking the shots or during post-processing.
The rule of 500 says that the maximum exposure time to avoid star trailing is 500 / effective-focal-length. My Nikon 5100 is an APS-C crop sensor with a multiplier of 1.5X which gives me at maximum exposure of 500 / (105 * 1.5) which is just 3.2 seconds. So, I am planning to piggyback the camera on my motorized/HEQ 5 Pro mount to track the stars and avoid trailing with the 20+ seconds needed to capture the stars in the cluster.
The hardest part may be getting a clear sky, in January, in Vancouver!
The RASC national office offers seven observing programs to promote active observing and has recently released videos about these programs that you can watch in this playlist.
The complete list of programs includes:
Explore the Universe — A program for the novice observer, covering all major astronomical objects, including constellations, bright stars, the Moon, the Solar System, deep-sky objects, and double stars. (Open to members and non-members).
Explore the Moon — An introductory lunar observing program based on 100 features in the RASC Observer’s Handbook.
Messier Catalogue— Follow Charles Messier’s 18th-century journey through the northern skies by observing his famous list of 110 “not comets,” including galaxies, nebula, clusters, and other deep-sky objects.
Finest NGC Objects — A slightly more challenging deep-sky program of 110 deep-sky objects for the intermediate observer
Deep-Sky Gems— An advanced list of 154 deep-sky objects (mostly galaxies) selected from David Levy’s 40+ years of comet hunting.
Observing programs are a great way to learn more about the night sky, challenge yourself, and to get the most out of our rewarding hobby. By successfully completing a program, a RASC member may apply for an official certificate for that program (non-members may apply for the Explore the Universe certificate). Several certificates come with lapel pins.