Indholdsfortegnelse for April 2020 i BBC Sky at Night

Early in the morning of 14 April 1970, the Apollo 13 mission was four- fifths of the way to the Moon when astronaut Jack Swigert followed a routine instruction and flicked a switch to stir the spacecraft’s liquid oxygen tanks. Fifty years on from the explosion this caused, the rescue mission that followed has lost none of its fascination, and this issue we celebrate its anniversary. On page 30 Elizabeth Pearson looks at events in the spacecraft and tells the astronauts’ story, while on page 36, Rod Pyle examines events on the ground at Mission Control and how this team turned a crisis 300,000km away into a ‘successful failure’. Also don’t miss our interview with one of Apollo 13’s Mission Control engineers on page 98. Still at NASA, he is…

Planet’s 18-hour year Astronomers have discovered an exoplanet that orbits its star in just 18 hours, the shortest year of any known planet. The world, NGTS-10b, detailed in a recent paper, is so close to its star it risks being torn apart by gravity. Astronomers will continue to watch the system to learn how long a planet can survive in such an extreme location. Martian rover named NASA’s Mars rover, formerly known as Mars 2020, has a new name – Perseverance. The new moniker was selected by an essay contest, the winning suggestion coming from 13-year-old Alexander Mather. “We are a species of explorers, and we will meet many setbacks on the way to Mars,” he wrote. “However, we can persevere.” Dying stars spin up asteroids The bright radiation of…

Each to their own I read with interest the Field of View article in the February 2020 issue regarding remote astronomy, in particular the comment relating to “opposition from some quarters”. Although I’ve not had the pleasure of indulging in remote astronomy, I think it’s a brilliant concept, giving access to professional grade equipment from some of the darkest skies on Earth, all from the comfort of your home – thousands of miles away in most cases. I can only imagine those folk who oppose such an idea are of a similar mindset to those who think, for example, that using image manipulation programs to get the very best from an astro image is cheating. Whatever one’s hobby, is it not best to use whatever technology is available to augment,…

David Griffin @griffolla Sad news. I’d been listening to her Cosmic Quest series on Radio 4 most nights before bedtime for about three years now. It’s fascinating and calming. Alan Dyer @amazingskyguy So sorry to hear the news. Heather was one of the great next generation of science popularisers following the lead of Sir Patrick Moore. She will be missed. Dean Jones @dean069 I used to watch her back in the ‘80s. She and Sir Patrick made me love astronomy Dr Patricia M Lewis @PatriciaMary I invited her to Geneva to @UNIDIR Annual Space Conference back in the day. She was very open about so many important and difficult issues – especially for women in science. Gareth Murtagh @garethjmurtagh What sad news, I loved her series The Planets made for…

‘Keeping It Simple, Straightforward, and Accessible’ (#KISSAstro) is one of the main tenets of Highlands Astronomical Society (HAS), the Inverness-based astronomy club with its own public access observatory next to the Culloden battlefield. With a 14-inch Meade Schmidt-Cassegrain telescope under the dome, the Jim Savage-Lowden Observatory is our pride and joy: we host public and members’ observing sessions there on most weekends from September until March. A state-of-the-art astro-camera links the scope to a warm room where people can view deep-sky objects in colour. The facility has opened up practical astronomy to young children and the disabled. HAS was formed in 1994 and has over 60 members, including a vibrant ‘Youngstars’ section for 8–14 year olds. The club meets from 7.30pm on the first Tuesday of each month in the…

11 April 19:13* Apollo 13 launches 14 April 03:06 Tank 2 stirred, explodes a minute later 14 April 03:08 “Houston, we’ve had a problem here” 14 April 04:37 Mission Control and the crew consider Aquarius as a lifeboat 14 April 05:13 Fred Haise shuts down last fuel cell – Moon landing now impossible 14 April 05:23 Odyssey’s systems turned off to conserve power 14 April 08:42 Mid-course correction nudges Apollo 13 into return trajectory 15 April 00:21 Apollo 13 disappears behind the Moon, before emerging 25 minutes later 15 April 13:22 Crew fabricate a carbon dioxide filter 16 April 11:33 Power transfer to emergency batteries begins 17 April 13:14 Service module separates, and the crew photographs the damage 17 April 15:23 Odyssey is powered back up in preparation for the…

DON’T MISS Venus against the PLEIADES BEST TIME TO SEE: All month. Closest approach 2–5 April Beautiful Venus has dominated the western twilight sky for many weeks and is now a familiar sight after sunset. The planet is very bright, shining at mag. –4.3 on 1 April, brightening to –4.4 by the end of the month. It’s favourably positioned for UK viewing, staying above the horizon for nearly five hours on 1 April and 4.3 hours on the 30th. Venus is easy to spot as soon as the Sun sets but this extended period above the horizon means that its visibility improves because there is time for the background sky to fully darken. At the start of April, Venus appears against an astronomically dark sky for 2.7 hours. By the…

It’s sometimes easy to forget that the Moon is a three-dimensional object. When we look at it from Earth, apart from slight libration variations, its features are the same one month to the next. Located around 384,400km away from Earth, the Moon is too far for our eyes to see in a way that allows us to perceive depth. However, looking at it through a telescope emphasises its physical shape and nothing does this better than observing round craters close to the Moon’s edge. This month’s Moonwatch target is the crater Blancanus located just to the south of the large, impressive walled plain of 225km Clavius. Blancanus itself is also quite large at 106km, but being close to the Moon’s southern edge, it appears foreshortened into an ellipse. The foreshortening…

When the Hubble Space Telescope was launched, 30 years ago this month, no one had ever heard about dark energy. But, in part thanks to Hubble, astronomers have come to realise that we live in an accelerating Universe, in which empty space is expanding ever faster and faster, thanks to this mysterious dark ingredient. This spring, a unique instrument mounted on a venerable telescope in Arizona has started compiling the most detailed 3D-map of the cosmos ever. The goal is to further our understanding of the expansion history of the Universe, and – hopefully – to uncover the true nature of dark energy. As physicists understand it, dark energy is a property of empty space. Like some sort of anti-gravity, it pushes empty space away from itself, accelerating the expansion…

Observing meteors is an interesting, albeit – with both the weather and the Moon to contend with – a sometimes frustrating pastime. In their most basic form, meteor watches are pretty easy to carry out, requiring nothing more than a pair of eyes and something to record your results with. As with all scientific recordings, there are guidelines to follow. Getting this right will elevate your observations and help advance our common knowledge of how specific meteor showers work. Best of all, it doesn’t take a lot of effort to get to this level and the resulting observations may help predict future meteor activity.…

Introducing Zenithal Hourly Rate (ZHR) Zenithal Hourly Rate (ZHR) is used to normalise meteor shower rates for comparative purposes and isn’t intended to represent expected visual rates. The term assumes a shower’s radiant is directly overhead (at the zenith), a perfectly clear, dark sky with a limiting magnitude of +6.5 and no visual obstructions. Few, if any of these conditions will be met in reality, so the actual number of meteors seen is often significantly lower than the quoted ZHR. Visual hourly rate (Nv) An observer’s visual hourly rate is the number of shower meteors recorded per hour. If the observing period is less than an hour, the count should be multiplied by 1 over the hour fraction (T). For example, seven shower meteors over 15 minutes (T = 0.25…

THE PLOUGH AND THE ‘W’ The Plough and a ‘W’ shape formed by Cassiopeia’s brightest stars appear to circle around Polaris, the North Star, every night. Use pointer stars Merak and Dubhe at the Plough’s front to find Polaris, then continue to Cassiopeia. If the skies are dark enough, you may be able to make out the rest of Ursa Minor’s dim stars. SPRING TRIANGLE The underappreciated Spring Triangle makes its way into the night sky in February, and by April it’s high enough to be a beautiful sight. Though the Triangle is broader than its summer cousin (see below), its corner stars Regulus (in Leo), Arcturus (in Boötes) and Spica (in Virgo) make this Triangle more understated. SUMMER TRIANGLE The Summer Triangle of Deneb (brightest star in Cygnus, the…

Exploding Stars and Invisible Planets: The Science of What’s Out There Fred Watson Columbia University Press £22 ● HB Astronomy is often said to be the oldest science and yet, for all our space exploration, we still have more questions than answers. Was there ever life on Mars? Is there a ninth planet hiding on the outskirts of our Solar System? How did the first stars form? Why can’t we detect the 95 per cent of the Universe that is ‘dark’? Are we alone? For people like Fred Watson – official Astronomer-at-Large for the Australian government – these enduring and evolving mysteries are the spice to a long career in astronomy and astronomy engagement, and this highly entertaining book is Watson’s love letter to the cosmos, complete with hand-drawn sketches…

1 Altair Tri-Pier Price £325 • Supplier Harrison Telescope Tel 01322 403407 • www. harrisontelescopes.co.uk Compact and portable, this pier provides a stable base for astronomy on the go. The swivel feet of the tripod ensure even surface contact, while the Tri-Pier weighs 8.9kg and comes with a padded carry bag. 2 PrimaLuceLab 2-inch robotic micro focuser Price £510 • Supplier Astroshop.eu Tel 020 3868 8042 • www. astroshop.eu Achieve extreme precision control of your focusing with the help of this robotic device. The focuser has a resolution of 0.04 microns per step and can be controlled via any Windows computer. 3 ADVANCED OVNI-M night vision eyepiece Price £5,449 • Supplier Astrograph Tel 0843 330 4988 • http: //astrograph.net Specifically designed for astronomy, this eyepiece uses the…

When to use this chart 1 Apr at 24:00 AEDT (13:00 UT) 15 Apr at 23:00 AEDT (12:00 UT) 30 Apr at 22:00 AEDT (11:00 UT) The chart accurately matches the sky on the dates and times shown for Sydney, Australia. The sky is different at other times as the stars crossing it set four minutes earlier each night. APRIL HIGHLIGHTS This month a meteor shower is ideal for Southern Hemisphere observers. Conditions for the Pi Puppids are perfect in 2020 with maximum expected around the 23rd, right on new Moon. They are visible from around 15 to 28 April. Although the Pi Puppid rates are low (typically 3 to 5 per hour) with the peak varying every year (40 per hour in 1977), they’re worth the wait, being bright…

Television Find out what The Sky at Night team have been exploring in recent and past episodes on page 18 Online Visit our website for competitions, astrophoto galleries, observing guides and more Social Media Follow us on Twitter, Facebook, and Instagram for space news, astro images and website updates Podcasts Listen to our Radio Astronomy podcasts where the magazine team and guests discuss astro news Tablet/phone Get each month’s issue on your Apple or Android device, now with bonus image galleries eNewsletter The best targets to observe each week, delivered to your inbox. Visit bit.ly/ skynewsletter Find out more at: www.skyatnightmagazine.com…

5 April 1978 On the 5 April 1978 episode of The Sky at Night, Patrick Moore talked with astronomer George Taylor from the Royal Greenwich Observatory. Since 1952, Taylor had been working on a new method to measure the size of asteroids using occultations. An occultation occurs when a foreground star passes in front of a background one, temporarily blocking out its light. By measuring the length of time the star blinks out, astronomers can gauge the size of the asteroid passing in front of it. Taylor was able to compute the times when occultations were likely to occur for the planets and 80 of the largest asteroids. When a potential occultation was due, he would pass the news to observatories who would pin down the orbits of the asteroid…

I was going through some old stuff at home recently and I found this letter. I was around 11, obsessed with astronomy and wrote to Patrick Moore using the address for BBC One’s Saturday morning magazine show Going Live! About two months later, I got his reply. It even has repeated letters from his broken typewriter. It inspired me so much. Michael Blair, @MichaelPBlair via Twitter Thanks for sharing your find, Michael. Patrick was a prolific letter writer and did so much to encourage people to look up and discover the cosmos.…

Email your queries to scopedoctor@skyatnightmagazine.com The Celestron Inspire 80AZ telescope is suitable as a beginner’s telescope. However, the 10mm and 20mm eyepieces supplied with the telescope are Kellners, which are an older three-element design. In this price range they will be somewhat inferior to the more modern four-element design of Plössls. After cataract surgery, I bought a Celestron Inspire 80AZ telescope with a Sky-Watcher SP 32mm eyepiece and a Moon filter. What can you suggest for me to get the most out of my telescope?DARREN LAMBERT You’d be better off using the 20mm version, as recent experience has found the 10mm version produces quite poor results, so you will likely be disappointed with the view. Your 32mm Sky-Watcher eyepiece will also serve you well. In the wake of your recent…

Kelling Heath Star Party Weybourne, Norfolk, 20–27 April If the clouds stay away, this should be a fun way to enjoy north Norfolk’s dark skies. The week-long event often hosts hundreds of amateur astronomers, and newcomers are welcome. Astro equipment vendors will also be on site. www.starparty.org Astrometry talk Bath Royal Literary and Scientific Institution, Bath, 3 April, 7.30pm The pioneering efforts to make a 3D map of our Galaxy are explored in this talk by ESA/Gaia project scientist Michael Perryman. He leads on Hipparcos and Gaia, two missions to measure the position and movements of a billion stars. Visitors £5; members/students £2. www.brlsi.org Stargazing at Low Force Waterfall Bowlees Visitor Centre, County Durham, 9 April, 9.30pm A beautiful dark-sky site and the drama of the Low Force Waterfall are…

As Venus is such a prominent object in the evening sky at the moment it’s easy to locate through a small telescope. Once the Sun has set, invite your young observers to find it using a telescope fitted with a low-power eyepiece. Once found, try increasing the magnification and ask them to record what they see. Repeat this over several nights spread over the course of the month. Venus is growing and showing as a beautiful crescent. Visually the view is quite beautiful, a close second to seeing the rings around Saturn in terms of wow factor. www.bbc.co.uk/cbeebies/shows/stargazing…

What is a meteor? The name meteor describes the phenomenon that occurs when a small particle – a meteoroid – enters Earth’s atmosphere and vaporises. From the ground, the swift moving path of light that results is what’s known as a meteor trail. An average trail is produced by a meteoroid similar in size to a grain of sand. Larger meteoroids will produce bright trails, and a trail brighter than mag. –4 (similar to Venus) is known as a fireball. Bright trails are often followed by a glowing column of ionised gas called a meteor train, which fades over time. Persistent trains may last for many seconds, becoming distorted by high altitude atmospheric winds. What is a meteor shower? Meteor showers are typically associated with comets, although a handful are…

Getting started 1 Date is normally stated as a double-date (say, 13/14 December 2020). This removes any ambiguity as it covers the evening to morning observed. 2 Observer(s) records the name(s) of anyone who contributes to the form. 3 Observing site identifies where you observed from, latitude and longitude being ideal. This can be obtained from a map or an online resource such as Google Earth. 4 Sheet of is used to ensure no loose sheets are missed, for example Sheet 2 of 4. 5 Correspondence address is where you can be contacted if the need should arise. 6 Observing conditions is intended as a general statement of the conditions throughout the watch. Augment with times if conditions vary greatly during the watch period. 7 Stellar limiting magnitude is a…

Rod Pyle Author and journalist “The Apollo 13 emergency could have been NASA’s darkest hour, but thanks to the efforts of legions of devoted people, it became its finest. It’s been thrilling to relive this bit of history!” Rod looks at Mission Control’s role in Apollo 13. page 36 Helen O’Brien Solar scientist “The launch of Solar Orbiter marks a new era in the understanding of our neighbouring star. I look forward to what we can expect from this Sun explorer as it sets out on its journey of discovery”. Helen updates us about Solar Orbiter. page 18 Scott Levine Astronomy blogger “I really enjoyed looking into the history of today’s constellations, and giving people a way to make the sky their own by creating their own asterisms.” Scott gets…

The world’s largest scopes rarely look at something as bright as Betelgeuse! The results were both stunning and intriguing, but they may not have happened without the contributions of thousands of amateurs, using the naked eye. As the star faded, there was debate about how unusual its behaviour was. The answer came from the American Association of Variable Star Observers (AAVSO). Its Betelgeuse observations stretch back to the 19th century. Red stars like Betelgeuse aren’t easy to monitor, and it’s so bright that there aren’t good, nearby comparison stars. But, thanks to the work of AAVSO, astronomers have moved quickly to investigate this dip. A triumph, perhaps, for the old-fashioned art of looking at the sky.…

“It’s more than 20 years since amateur astronomer Yukio Sakurai noticed what he thought was a nova in Sagittarius” We’re so used to the astronomical world being static and unchanging that even small alterations, like this year’s fading of Betelgeuse in Orion, can be both surprising and somewhat unsettling. For some objects, though, change is just a way of life, and that’s certainly true of Sakurai’s Object, the subject of this month’s paper. It’s now more than 20 years since the Japanese amateur astronomer Yukio Sakurai noticed what he thought was a nova in the constellation of Sagittarius. Follow-up observations soon showed it to be something rather more interesting. It appeared to be a normal supergiant star, but its spectrum kept changing and, in 1997, Sakurai’s star began producing a…

On 9 February 2020 ESA’s Solar Orbiter launched on its journey to the Sun. Armed with a suite of instruments, the orbiter will study how the stream of charged particles emanating from the Sun, known as the solar wind, affects and influences the planets and other bodies of the Solar System. This month The Sky at Night team go behind the scenes to learn more about the spacecraft and this exciting mission. BBC Four, 12 April, 10pm (first repeat BBC Four, 16 April, 7.30pm) Check www.bbc.co.uk/skyatnightfor subsequent repeat times…

Vikki Kim Heather Couper got me into the stars and Universe when I was a youngster! RIP Heather another bright star in the sky. Sonja Charters I met her on an astronomy trip to watch the total eclipse in Hawaii many years ago. Sleep well among the stars Heather. David Greensmith Sad news. I think she was the first woman astronomer I ever saw on TV. Graham Woodall May she rest in peace. I really enjoyed watching her enthusiasm for space when I was growing up. Mark Plas I loved the series The Planets, presented by Heather, which aired in the Netherlands in the late 1980s and early ’90s. Cate Walker Lovely voice, superb presentation skills and amazing knowledge which transformed the way we looked at the stars and space.…

Binoculars are excellent for observing the night sky but it is important to buy a pair that you can handle while maintaining a good grasp. High magnification instruments are more difficult to hold steady. Binoculars are always marked with two numbers, for example 10x50. This means that the magnification is 10x and the aperture is 50mm. There is often additional information describing the field of view, for example 80m at 1,000m indicates you’ll be able to see an area 80m across 1,000m away. You can convert the field width to degrees, a more useful measurement for astronomy, by copy-pasting the following formula into a cell on a spreadsheet: =DEGREES(ATAN(Field width in metres/2000))*2 Steve Richards is a keen astro imager and an astronomy equipment expert…

This year the Edinburgh Science Festival is hosting a range of science workshops, talks and demos across the Scottish capital. While the 2020 festival’s theme is ‘Elementary’ – exploring Earth, Air, Fire, Water and the Aether – many events will also take a look at the wider Universe. Artist Luke Jerram’s 7m-wide model of Earth – constructed using NASA imagery – comes to Edinburgh for the first time. It’s 1.8 million times smaller than the real thing and will be available for drop-in visits throughout the festival. This year’s talks include Exploring Space Science, a discussion of how the workings of the cosmos impact daily life on Earth; What is Out There?, exploring the potential for life beyond Earth; and Interstellar Medicine, looking at how procedures can be adapted in…

Commander: James ‘Jim’ Lovell Lovell was a spaceflight veteran, having flown in Gemini 7, Gemini 12 and Apollo 8. During the latter, he trialled a method of navigation using Earth’s terminator which he used again during the Apollo 13 disaster. Like all the Apollo 13 crew, he never flew in space again. Lunar module pilot: Fred Haise Before joining NASA, Haise served in the Marines and the Air Force. He was meant to fly on Apollo 19 but this was later cancelled, and he moved into development of the new Space Shuttle. He went on to work for Grumman Aerospace Corporation, the company which built the lunar modules, including Aquarius. Command module pilot: Jack Swigert Swigert was in the Air Force and worked as a test pilot before joining NASA…

Universal time (UT) and British Summer Time (BST) Universal Time (UT) is the standard time used by astronomers around the world. British Summer Time (BST) is one hour ahead of UT RA (Right ascension) and dec. (declination) These coordinates are the night sky’s equivalent of longitude and latitude, describing where an object is on the celestial ‘globe’ Family friendly Objects marked with this icon are perfect for showing to children Naked eye Allow 20 minutes for your eyes to become dark-adapted Photo opp Use a CCD, planetary camera or standard DSLR Binoculars 10x50 recommended Small/ medium scope Reflector/SCT under 6 inches, refractor under 4 inches Large scope Reflector/SCT over 6 inches, refractor over 4 inches GETTING STARTED IN ASTRONOMY If you’re new to astronomy, you’ll find two essential reads on…

What equipment should you take? Typically, equipment for observing a meteor shower doesn’t need to be elaborate or expensive. A clipboard, dim red torch, accurate watch and a ruler or piece of string will suffice. Meteor reporting forms (see p71) can be downloaded from organisations such as the British Astronomical Association (britastro.org), while a dim red torch allows you to look at the form and (unilluminated) watch without ruining your dark adaptation. If you want to plot trails, widefield charts can be pre- printed prior to the session. These can be generated from many planetarium programs such as the freeware Cartes du Ciel (www.ap-i.net). A ruler or piece of string is useful to hold up to the sky to check on the path of the trail, a good way to…

► The Stellarium planetarium program: make sure you have the latest version of the software installed. ► A camera: a DSLR or mobile phone can be used to take the images required for your new landscape. If your phone takes wrap-around landscape images, this may make it easier, depending on the saved file format. ► Mosaic-stitching software: Microsoft Image Composite Editor (ICE) is great for stitching mosaics together for your landscape, before using an image-editing program to create the final image. ► Image-processing software: any image-processing program can be used such as Adobe Photoshop or Affinity Photo.…

Whether you’re a seasoned astro- photographer or a beginner, we’d love to see your images. Email them to contactus@skyatnightmagazine. com. Ts&Cs: www.immediate.co.uk/ terms-and-conditions We’ve teamed up with Modern Astronomy to offer the winner of next month’s Gallery a finder–guider adaptor, which connects T-thread guide cameras from ZWO, Orion and others to 9 x 50 standard finders from Sky-Watcher. The accessory comes with full instructions and support. www.modernastronomy.com • 020 8763 9953…

The Altair 70EDT-F is a travel-friendly refractor with premium optics, offering the choice between grab-and-go visual observing and astrophotography. Our review telescope came as a package, including a 0.8x reducer/flattener lens which corrects for inherent coma and takes the 70mm diamater lens from an f/16 to an f/4.8 and a working focal length of 335mm. This means that when it’s combined with a DSLR or a dedicated astro camera, the 70EDT-F can present images with a field of view that’s easily wide enough for a large nebula such as the Orion Nebula, M42, or extended star clusters like the Pleiades, M45. Making an impression The telescope has a stylish appearance, combining classic white with red anodized trimmings, and it has the look and feel of a well-made instrument. Although its…

How did you first get interested in astronomy? I grew up in postwar Britain and went to school in the 1950s and ’60s. Space science and astronomy were the hot topics and I was just as star-struck as everyone else. But I remained star-struck for the rest of my life. I worked at both Royal Observatories in the UK before coming to Australia on deployment to the UK Schmidt Telescope. For 20 years, I was Astronomer-in-Charge of the Australian Astronomical Observatory, managing its scientific output and helping to protect its night skies from light pollution. When the observatory transferred to the university sector I was appointed the nation’s first Astronomer-at-Large. It’s an outreach and advocacy role, and it’s my dream job. It lets me talk astronomy, space and STEM to…