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Star Gazer News Astronomy News for Bluewater Stargazers Vol 14 No.2 Mar/Apr 2020 Mar/Apr 2020 SGN Contents p 1: From the President; and a home for the dome! p 2: Southern Cross spotted -twice. p 3: Special Feature: What’s going on with Betelgeuse? p 4: Betelgeuse: Comparison images p 5: Betelgeuse: pronunciation and dimming explained? p 6: New aurora type discovered -amateurs helped again! p 7: More about “dune” aurora p 8-10: Quetican Field of View: Iceland: Fire and Ice This month’s feature constellation (see pg 13) is Orion, the p 11: Sky Sights: March/April Hunter. Three articles on Betelgeuse can be found on pg 3 to p 12: Sky Sights: (cont’d) 5. In Orion this winter, note the star α-Orionis (Betelgeuse). Its p 13: Constellation page: Orion p 14: Miscellaneous Page and Classifieds magnitude has noticeably dimmed and it now shines fainter p 15: Image of the Month: Milky Way from Machu Picchu than Bellatrix (magn. 1.64) in Orion’s other shoulder. See pg 4 for more about observing the brightness changes yourself. From the President: The weather gods treated me very perversely over the The charming cartoon above was drawn by astronomy last two weeks of January. Rebecca and I decided to professor George Reed (West Chester University), who take a holiday away from the snow and ice by travelling promoted astronomy in his courses/planetarium programs. I to Peru and Ecuador to visit Machu Picchu and the came across these first when his complete sky charts were Galapagos Islands. This is the low season down there published in May 1980 in Sky&Telescope. They remain my but it also happens to be the rainy time of year (I found favourites. George Reed passed away August 2016. that out after we had booked!). So we packed our rain Coleman Dome Stays in Bruce! gear and anticipating cloudy weather I did not take any of my DSLRs to do any astro imaging. So, guess what? Over the two weeks we were there we got a total of about 2 hours of rain. Most days were either bright and sunny (Peru) or just cloudy and pleasantly warm. The Galapagos were downright hot and very humid. Zeus, (the god of the sky, rain, thunder and lightning) must have been otherwise occupied. In Cusco, Peru, there were nights when the skies were clear and I saw Venus near the crescent Moon on several occasions. Also during an early morning transfer to the airport for a morning flight to Quito, up in the sky was the Southern Cross with α and β-Centauri nearby. (See pg 2). Cusco was the farthest south we got, 13° BAS member Frank W. has rescued the Coleman Dome. below the equator so Orion which is on the celestial Frank plans to refurbish it atop a suitable building to add equator would be past the zenith to the north by that another observatory to his Allenford “complex”. Frank has amount. It was strange to see it lying on its side. Also contacted ObservaDome which built it in the 1970’s for strange was the fact that the first crescent Moon was parts to bring it back up to operating condition. Let Frank sunlit on the east side like a last crescent in northern know if you would like to help out in the rebuild project. It skies. And Venus sank virtually straight down into the would be good experience to see how one of these comes horizon in the west. Lesson learned: Always, always, together. He already has one volunteer -the guy who helped always pack your best camera on trips! take it apart -that was a sad day…) S G N Crux Spotted Mar/Apr 2020 pg 2 Disclaimer: S G N reports on the activities of the Bluewater BAS Executive 2020-2021 Astronomical Society (formerly Bruce County Astronomical President: John Hlynialuk [email protected] Society) but any opinions presented herein are not necessarily V-President: Eric Ingard [email protected] endorsed by BAS. See the BAS website at Secretary: Lorraine Rodgers [email protected] www.bluewaterastronomy.com for up-to-date details relating Treasurer: Cheryl Dawson [email protected] to BAS events. SGN is produced and edited by John Hlynialuk Memb-at-Lrg: Zoë Kessler [email protected] and I am solely responsible for its content. Your original articles, Membership: Marian Ratcliffe [email protected] images, opinions, comments, observing reports, etc., are welcome. I reserve Past Pres: Brett Tatton [email protected] the right to edit for brevity or clarity. Errors or omissions are entirely mine. I will not publish your emails or other materials without your specific permission. No part of this publication shall be reproduced in any form whatsoever without the editor’s consent. However, the Sky Calendar and Feature Constellation pages are free to copy for non-commercial use. Feel free to forward this issue in its entirety to friends. Email comments and/or submissions to [email protected] Southern Cross spotted The first time I saw Crux was in 2011 on a trip to do astronomy in Chile. (Image at bottom). A lot of planning went into that sighting, but the second time I spotted Crux was totally by accident. On Jan 27, Rebecca and I were waiting for an early morning transfer to the Cusco airport after our visit to Machu Picchu and the hotel where we waited for the cab happened to have an open air courtyard. Up in the sky was the Southern Cross with alpha and beta-Centauri neatly framed by the two-story structure. At 4:58 am Crux was about 42° in elevation. (Image right). The only camera I brought was a Canon point-and-shoot but it did have a long exposure setting. I captured both Crux and to its left the two brightest stars in Centaurus. Dawn was breaking so it is not the best shot I have ever taken. The image lower right taken with a proper DSLR on a tracking mount shows what the area looks like from a dark sky site (Chile, 2011). Image right: Southern Cross on Apr. 1, 2011 from San Pedro de Atacama. The fifth star of the asterism, the “base runner” is visible between “2nd and 3rd base”. Lower right of frame is the eta- Carina Nebula; the “star” in upper left is actually the globular cluster omega- Centauri, which was labelled a star by early mappers. The dark patch below Crux is the Coalsack Nebula. The Incas say that the god Ataguchu, in a fit of temper, kicked the Milky Way and a fragment flew off, forming the Small Magellanic Cloud leaving the black mark of the Coalsack behind. Beware of Inca gods in a bad mood! In this shot alpha and beta Centauri are left of photo. Canon 50D, 118 s exposure at ISO 2000, f/4.5 at 38 mm focal length (17-85 mm zoom). Image piggy back Polaris mount. S G N What’s Happening to Betelgeuse? Mar/Apr 2020 pg 3 ! Betelgeuse Fades from 0.5 to 1.66 Magnitude! Universe Today reports that Betelgeuse keeps getting dimmer and dimmer and everyone is wondering what exactly that means. The star will go supernova at the end of its life, but that's not projected to happen for tens of thousands of years or so. So what's causing the dimming? Villanova University astronomers Edward Guinan and Richard Wasatonic were the first to report Betelgeuse's recent dimming and in a new post on The Astronomer's Telegram, they report a further dimming of Betelgeuse. They also point out that although the star is still dimming, its rate is slowing. Betelgeuse is a red supergiant star in the constellation Orion. It left the main sequence about one million years ago and has been a red supergiant for about 40,000 years. It's a core- collapse SN II progenitor, which means that eventually, Betelgeuse will burn enough of its hydrogen that its core will collapse, and it will explode as a supernova. It's a semi- regular variable star, with cycle of about 420 days long, and another of about five or six years. A third cycle is shorter; about 100 to 180 days. Though most of its fluctuations are predictable and follow these cycles, some of them are not, like the current dimming. This artist’s visualization shows Astronomers have been monitoring Betelgeuse for a long time. Visual estimates of the star go back about 180 years, Betelgeuse as it was revealed by new and since the 1920s, the American Association of Variable observation techniques with ESO's Star Observers (AAVSO) have taken more systematic Very Large Telescope. These measurements. About 40 years of photometric measurements observations led to the sharpest-ever by Villanova University astronomers show the star is as dim looks at the star. (Image credit: ESO/L. as it's ever been. Calçada) According to Guinan and Wasatonic's post on Astronomer's Telegram, Betelgeuse's temperature has dropped by 100 Kelvin since September 2019, and its luminosity has dropped by nearly 25 percent in the same time frame. According to all happen, they just don't know when. Whatever the cause, we of those measurements, the star's radius has grown by about know the eventual end: a supernova explosion. 9 percent. This swelling is expected as Betelgeuse ages. Whether this dimming is directly related to the approaching Betelgeuse is close in astronomical terms, only about 650 cataclysmic death of this unstable star is unknown. As Guinan light-years away, and that makes it the only star other than our and Wasatonic say on Astronomer's Telegram, "Betelgeuse Sun on which we can see surface details.