Indholdsfortegnelse for August 2020 i BBC Sky at Night

Visit www.skyatnightmagazine. com/bonus-content/Y4Y6SQV/ to access this month’s selection of exclusive Bonus Content AUGUST HIGHLIGHTS Interview: The End of Everything From ‘heat death’ to the ‘big rip’, astrophysicist Katie Mack reveals how the Universe might end. Watch June’s episode of The Sky at Night Maggie talks to NASA astronaut Jessica Meir about life on the ISS and taking part in the first all-female spacewalk. Audiobook preview: Amazing Stories Download and listen to two chapters from US space writer Rod Pyle’s book Amazing Stories of the Space Age. The Virtual Planetarium Pete Lawrence and Paul Abel guide us through the best sights to see in the night sky this month.…

Pluto might have had a hot start, a new study suggests. Planetary scientists know the dwarf planet currently has a subsurface water ocean, but they are uncertain about how long it has been there. The traditional formation theory has Pluto beginning as a frozen ball which was later thawed by radioactive rocks, but another theory proposes that the dwarf planet retained enough heat from its genesis to maintain a liquid ocean throughout its life. These two processes both involve complex, but different, patterns of thawing and refreezing. Each creates a specific type of surface feature, which geologists can use to differentiate between the two theories. “Now that we have images of Pluto’s surface from NASA’s New Horizons mission, we can compare what we see with the predictions of different thermal…

There’s something of an annual stargazing ritual. In the same way that many of us go through the Christmas Radio Times, circling the films and TV specials we want to watch, at the start of every year amateur astronomers check the observing prospects for eclipses, comets and the planets during the months to follow. They also want to know how the major meteor showers will be affected by the Moon, especially the best shower of the year, the Perseids, which peaks in mid-August. Guides to 2020 advised us that this would be a challenging year for Perseid watchers, when a last quarter Moon will be close to the shower radiant over the peak period. This means that fainter Perseids won’t be seen, and we’ll have to wait longer between meteors…

On Thursday 18 February 2021, with protection from a heat shield and 20m-wide parachutes, NASA’s Perseverance rover is scheduled to descend through the thin Martian atmosphere. Minutes later, the six-wheeled machine will be lowered to the Red Planet’s surface from a sky crane that is hovering at low altitude. Perseverance will not be alone. Around the same time the UAE’s Hope spacecraft will enter the orbit of Mars to study the planet’s atmosphere and climate; and a few months later the lander part of the Chinese Tianwen-1 mission will touch down elsewhere on the Red Planet, releasing its own miniature rover to explore the desert world. All three missions are scheduled to launch this July and will take about seven months to reach Mars. The simultaneous timing is no coincidence:…

Mars Best time to see: 31 August, 04:00 BST (03:00 UT) Altitude: 43˚ Location: Pisces Direction: South Features: Dark ‘albedo’ features, polar caps and weather Recommended equipment: 150mm or larger Mars reaches opposition in mid-October, a time when it appears largest and brightest for the current period of observation. A planet is said to be in opposition when the Earth lies directly between it and the Sun. The last Mars opposition was poor as seen from the UK since it was never all that high, but this time it occurs at a greatly improved altitude, which is all the more exciting. During August Mars builds on the already impressive performance boost it got in July. Last month it moved from a compromised morning location to one where it appeared high…

Ceres is a world of many designations; it was the first minor planet or asteroid formerly identified. This event occurred on 1 January 1801, its discoverer being an Italian monk called Giuseppe Piazzi. He was working at the Palermo Astronomical Observatory in Sicily at the time. While searching for a particular star, he observed moving Ceres and believed he had stumbled upon a comet. He followed the object for 41 days after which time he became ill, just as the Sun began to interfere with the field of view. With just 41 days of observations, many doubted that the mathematics of the time could predict where Ceres would be after re-emerging from the Sun’s glare. Mathematician Carl Friedrich Gauss saved the day, discovering a method for computing its orbit. He…

Star trails are made up of multiple merged images, each of around 30- to 60-second exposures. These can either include a foreground for effect or they can be a full circle of star trails with Polaris in the centre. To achieve a decent curvature on the trails, set aside two to three hours to gather enough images. The longer exposures mean that ISO levels need to be managed – if the ISO setting is too high, the final image may be noisy or light polluted. Here, get to know the camera; it might be that you prefer the effect of a 25-second exposure at ISO 3200 over a 40-second exposure at ISO 800. It will also depend on local surroundings and the time of year you’re imaging. If using an…

Although seemingly empty, the space between the planets of our Solar System is teeming with vast numbers of meteoroids, small pieces of rock and dust largely originating from comets and asteroids but also, to a lesser extent, from the terrestrial planets and rocky satellites. A small number even originate from outside our Solar System: so-called interstellar dust. Meteors are produced when these particles enter Earth’s atmosphere at extremely high speeds (ranging from around 11km to 72km per second) causing them to burn up and leave a bright momentary streak across the sky. Earth encounters approximately 40,000 tonnes of extraterrestrial dust every year. Although this may sound like a lot, on a typical night it means you might see just a few meteors an hour streaking randomly across the sky. These…

STEP 1 Choose your lens: a 14-20mm focal length is ideal, and the fastest possible is recommended. Lens speed is measured by the lowest value the focal ratio (f-number) can be set to. An f/2 setting will do better under low light than one of f/3.5. You could have one camera for wide-fields, and one at a longer focal length for narrower views. STEP 2 You don’t necessarily need a tracking mount for meteor imaging. A sturdy tripod will be adequate. If you do choose a tracking mount, make sure it’s not going to rotate the camera into a position where part of the sky is obscured later on. Aim the camera at an altitude 60° above the horizon, with the centreline of the long frame axis pointing back towards…

Explore Scientific has been manufacturing telescopes, mounts and eyepieces for a good while and now it has launched a range of cooled one shot colour (OSC) CMOS cameras aimed at deep-sky astrophotography. Here we take a look at the Deep Sky Astro 7.1MP, which uses an impressive Sony Exmor IMX428 CMOS colour sensor. The camera is supplied in a tough black plastic case, along with all the accessories that you’ll need to get started, including a software disc to install all the drivers and software. With a nice solid feel, the Deep Sky Astro 7.1MP camera is made from lightweight aluminium anodised in blue. On its back you’ll find the main USB 3.0 socket and a USB 2.0 hub for additional connectivity. There is also a bank of small LED…

Hubble reveals the spectacular demise of the ‘Jewel Bug’ Nebula HUBBLE SPACE TELESCOPE, 18 JUNE 2020 The ‘Jewel Bug’, the ‘Gummy Bear’ and the ‘Magic Carpet’… planetary nebula NGC 7027’s various monikers over the years all hint at its intriguingly idiosyncratic shape, revealed more spectacularly than ever before in this new image. Taken for the first time with the full range of Hubble’s Wide Field Camera 3 instrument, spanning from near-ultraviolet to near-infrared light, it shows an incredibly complex and rapidly evolving picture. Fast stellar winds slam into slowly expanding dense clouds of dust, creating bubble-like cavities and jets. Scientists suspect the eccentric patterns point not to one but two dying stars at its centre. They may have been placidly interacting and throwing out material for thousands of years but…

A project to map the outer edge of the Solar System has just completed an entire solar cycle’s worth of observations. For the last 11 years, NASA’s Interstellar Boundary Explorer (IBEX) has mapped the bubble of particles created by the solar wind, known as the heliosphere. With a complete cycle now observed, astronomers are able to look at how the heliosphere responds to the Sun’s changing activity, such as how it inflates like a balloon when the solar wind gusts. “It takes [two to three] years for these effects to reach the edge of the heliosphere,” says Jamey Szalay, an IBEX researcher from Princeton University. “For us to have this much data from IBEX finally allows us to make these long-term correlations.” http://ibex.swri.edu/ Turn to page 60 to discover more…

A distant star and its planet, which bear a close resemblance to our own Sun and Earth, have recently been discovered. The planetary system was found in data from the exoplanet-hunting Kepler Space Telescope, which looked for dips in brightness caused by planets transiting across their stars’ discs. This photometric transit method favours the detection of Earth-sized planets around dim, red dwarf stars rather than around those like our Sun. Red dwarfs are relatively cool, however, and emit high-energy solar flares, characteristics which could render such planets more hostile to life. But Kepler-160, the host star of this newly discovered planet, is only slightly larger than our Sun and has a temperature of 5,200˚C – only 300˚C cooler. Astronomers already knew the star had two Neptune-sized planets from an initial…

The ‘Sky Guide Challenge’ in July was to try to observe the central white dwarf star in the Ring Nebula, M57. I have just taken up the steep learning curve that is astrophotography and decided to have a go at imaging M57 as my very first target a couple of weeks ago. This is my finished result (right). I’m really pleased with my first effort, especially as I forgot just how small M57 appears in the eyepiece. My setup was a Sky-Watcher 80ED on a Celestron AVX mount, with an unguided Canon EOS D500 DSLR camera controlled by APT on my laptop. I took 30 light frames, 20 darks and 40 bias (but no flats as I knew I’d need to heavily crop), stacked them in DSS and processed the…

It’s very simple – the darker your sky, the more you will see in it, so try your best to get away from as many street lights, security floodlights and illuminated buildings as you can and you’ll see thousands more stars than you can from your garden. You’ll also see more Perseid meteors, not just the really bright ones. Your ideal Perseid-watching site will be not just far away from static sources of light pollution, but also from the headlights of passing traffic. As tempting as it might be to pull out your phone during lulls in meteor activity to check the weather or social media reports of what others are seeing: don’t. The glare from your phone’s screen will ruin your dark adaptation in a moment, and you’ll have…

The European Space Agency’s (ESA’s) Rosalind Franklin rover has been beset with problems, predominantly with its giant parachutes. While these issues have now been solved, says project scientist Jorge Vago, they couldn’t be executed in time for the launch – partly due to travel restrictions imposed by COVID-19. “As it is, the earliest we will be able to execute these tests is late September 2020,” says Vago. Rosalind Franklin – named after the British co-discoverer of DNA – is part of ESA’s ExoMars programme. Russia is providing the Kazachok lander that will deploy the rover to the surface and the Proton-M rocket which will launch it in September 2022, aiming for an arrival in spring 2023. According to Vago, the project’s delay provides an opportunity to carry out a few…

KEY TO STAR CHARTS When to use this chart 1 August at 01:00 BST 15 August at 00:00 BST 31 August at 23:00 BST On other dates, stars will be in slightly different positions because of Earth’s orbital motion. Stars that cross the sky will set in the west four minutes earlier each night. How to use this chart 1. Hold the chart so the direction you’re facing is at the bottom. 2. The lower half of the chart shows the sky ahead of you. 3. The centre of the chart is the point directly over your head. Sunrise/sunset in August* Moonrise in August* Moonrise times 1 Aug 2020, 20:12 BST 5 Aug 2020, 22:13 BST 9 Aug 2020, 23:10 BST 13 Aug 2020, 00:04 BST 17 Aug 2020, 03:10…

Lyra, the Lyre, is a distinctive summer constellation: its alpha star Vega is the fifth brightest in the night sky. Southeast of Vega is a distinct squashed diamond pattern formed from Sheliak (Beta (b)), Sulafat (Gamma (g)), Delta (ð) and Zeta (z) Lyrae. Sheliak is the mag. +3.3 star marking the diamond’s southwest corner. Sheliak is actually a multiple star system that is around 960 lightyears away. The system has three main components: Beta Lyrae A (variable magnitude, +3.3 to +4.3), B (mag. +7.2, 46 arcseconds from A) and C (mag. +9.9, 86 arcseconds away). Stars B and C are singles, while A is another multiple. Beta Lyrae A comprises an eclipsing binary pair identified as Aa and a single star Ab. The former, labelled Aa1 and Aa2 consists of…

Step 1 After carefully drilling holes (approximately 18mm diameter) in the base and lid, paint the inside of the tube with matt black spray. We shook some sawdust around inside when the paint was wet and then repainted it to make it really non-reflective. Step 2 Taking care, form the slit by taping two fresh razor blades across the hole in the base. We taped up one side of each blade first to minimise the risk of injury while we experimented with the gap where wider equals brighter, narrower equals finer definition. Step 3 Cut a small section from the CDR and then peel off the foil label by applying, then removing, sticky tape. Cut a holder (with a 12mm hole) from some card. This will be taped to the…

The Moon looks more or less colourless through a telescope. Even the Apollo astronauts observing it up close, described it as mainly grey, or slightly brown. But the Moon’s surface material, known as regolith, does have very subtle colour differences, which are dictated by the mineral composition in any particular area. This mineral distribution on the lunar surface was mapped in great detail by the US Clementine probe in 1994, but the good news is that you can produce images showing these colours without having to launch a spacecraft to do so. It’s easily achieved and all you need is a one shot colour (OSC) camera and a telephoto lens or telescope, plus a bit of image-processing knowhow. As with most image processing, the success of the technique relies on…

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What are the major challenges of setting up a base on the Moon or Mars? The two major challenges are adjusting to different gravity regimes and radiation. The Moon is close by so it takes a short time to get there. When you land it’s a sixth of Earth’s gravity, and there’s no atmosphere so the radiation’s harsh. Mars is a longer trip; six months to get there, a year and a half to get planetary alignment, then six months back. The Martian atmosphere provides a bit of protection and the gravity is a third of Earth’s. Then you need a home; you have to keep the atmospheric pressure up inside because you want to be able to breathe and not be in closed mobile spacesuits all the time. What’s…

A ripple in space time has allowed astronomers to discover a rare object that bridges the gap between black holes and neutron stars, a recent report has announced. The find could give astronomers insight into how these dense objects form. Black holes and neutron stars are both incredibly dense objects created during the deaths of the Universe’s largest stars. Which one forms depends on the mass of the dying star, with black holes arising from the largest. Over the years, astronomers have found no neutron stars heavier than 2.5 solar masses, while the lightest black hole discovered is 5 solar masses, leaving a ‘mass-gap’ where no objects seem to exist, until recently. Last summer, astronomers at the LIGO and Virgo interferometer observatories were searching for gravitational waves, ripples in space…

An initiative hunting the skies for signs of intelligent life, Breakthrough Listen, has released a list of 700 targets of potential interest in June. The ‘Exotica’ catalogue contains one of almost every kind of astronomical target in the observable Universe – from ordinary comets to the most exotic galaxies. Its aim is to increase the diversity of targets being explored for technosignatures – indicators such as radio waves or laser pulses being given off by an advanced civilisation. This will help astronomers broaden their search for intelligence away from only environments that resemble Earth, to include a full range of possible habitats. “When it comes to the search for intelligent life, it’s vital to have an open mind,” says S Pete Worden, executive director of the Breakthrough Initiatives. “Until we…

Though most of the world’s professional telescopes shut down for several months due to the COVID-19 pandemic, astronomers did not sit idly at home. Two scientists, Daniel Stern and Dominic Walton, spent the time going through 20-year-old data, unpicking the mysteries of the first Einstein ring ever discovered. An Einstein ring forms when light from a distant object is bent by gravity, which distorts its image into a ring shape. Astronomers found the first one in 1987, though it has been observed by many NASA telescopes since and the data is now publicly available. “As we dug deeper, we were surprised that such a famous and bright source never had a distance measured for it,” says Stern, from NASA’s Jet Propulsion Laboratory. Using the archived data, the pair measured that…

As a British-Indian woman, growing up, I sometimes felt a bit awkward about my career path into the space industry. I was often surrounded by doctors, dentists and pharmacists, and the elder generation didn’t understand why I might want to pursue a career in astrophysics. Today, I hope to inspire young people from all backgrounds to pursue a career in astronomy or geophysics, regardless of ethnicity, gender or social mobility. I work with the Committee on Diversity in Astronomy and Geophysics (CDAG) at the Royal Astronomical Society (RAS) and other organisations to study and improve diversity, but this is no mean feat. One of the defining features of space and astronomy is that it should be accessible to everyone. We are one human race, on one planet, all looking up…

One of the most important tasks of NASA’s Perseverance rover is to collect soil samples and prepare them for a future return to Earth, where geologists and astrobiologist can study them in fully equipped terrestrial laboratories. “It’s thrilling to think that these samples have the potential to lead to major, possible paradigm-shifting discoveries about Mars, our Solar System, and life beyond Earth,” says deputy project scientist Katie Mack. Perseverance will seal the precious material – pebbles, soil and atmosphere – in some 40 titanium capsules that will be left at a small number of recovery spots, to be collected by a future space mission – probably a NASA/ESA collaborative effort. This new, as-yet undefined (and un-funded) mission will comprise an orbiter, a lander, a small rover, some sort of capsule…

2020 PERSEIDS BEST TIME TO SEE: 1–23 August, peak on the night of 12/13 August August is the month when the Perseid meteor shower reaches peak activity. Fortunately, it’s one of the most prolific showers in the annual calendar and a fairly reliable performer. The enemy of meteor showers is moonlight and this year, although present, the Moon should be reasonably manageable. The Perseid peak for 2020 is expected to occur between 14:00 BST (13:00 UT) and 17:00 BST (16:00 UT) on 12 August which is, of course, during daylight hours. This means the best opportunities for spotting Perseid meteors will be on the nights of 11/12 August and 12/13 August. On the night of 11/12 August the Moon will be just after its last quarter phase, 47%-lit. It rises…

1. The Scutum Star Cloud We’ll begin with the astonishingly rich star field in the northeast quarter of Scutum. It’s so easy to find that it has been mistaken for a real cloud on a clear night. Look for the ripples of stars, formed by the indistinct dark nebulae that weave among them. You should also see the even richer condensation of nearly 3,000 hot blue stars that forms the densest of all open clusters, M11, the Wild Duck Cluster. SEEN IT 2. The Swan Nebula M17 Next, identify Gamma (γ) Scuti and pan 2.5˚ to the southwest, where you will find a misty patch that Charles Messier described as, “A train of light without stars, in the shape of a spindle, of 5 or 6 minutes in extent.” Keep…

Astrophotography is a steep learning curve for everyone, with lots of questions to consider. What kind of images do you want to capture? What kind of equipment do you have (and what sort do you need)? What are the best camera settings to use? Then there’s the late nights to consider, the time required and of course the weather. Yet astrophotography is a labour of love and when it goes right, it can be extremely rewarding. While the logistics of imaging are one set of challenges, knowing what to do with the data in the morning is another. This is where image processing – enhancing a digital image to improve its visual appeal with computer programs like Adobe Photoshop or GIMP – comes in. It’s a major part of an…

Practical astronomy projects for every level of expertise DIY ASTRONOMY This month we revisit a classic project for demonstrating the nature of light – a spectrograph, which can be used visually and with a smartphone or a hand-held camera. We have provided plans and extra photos to help, along with key dimensions, but because your phone and tube size may vary, you might need to adapt these to suit. To use the spectrograph, simply point the front towards the bright object you are studying. When you look into the back you’ll see that the light from the source is spread out into a rainbow-like spectrum. Bright coloured bands or dark gaps in an otherwise continuous spectrum can reveal a lot about the nature of the source. If you mount your…

August means that the peak season for meteors is upon us, including the Perseids. In fact, there are many meteor showers active from the end of July into August, and their activity overlaps. As a result, if skies are clear and dark, there’s a good chance of seeing a meteor at this time of year. Two additional factors make August meteor-hunting pleasurable. For starters it’s a relatively warm month; it can get chilly at night and the evenings are a bit damp, but overall the conditions are far more comfortable than they are for spotting the Geminids in December. The next factor is the night’s length. While it takes stamina to stay up from dusk to dawn in mid-winter, a full night watch at the start to middle of August…

Leo Triplet Mukund Raguram, Lake Sonoma, California, 21 March 2020 Mukund says: “Galaxy season can sometimes feel challenging for imagers with smaller refractors, but the Leo Triplet – NGC 3628 (top), M66 (left) and M65 (right) – looks good at any focal length. I drove to the darkest skies in my region to shoot this target and was pleased to pick up NGC 3628’s very faint tidal tail. The seeing was excellent and I’m happy with the level of detail in each galaxy.” Equipment: ZWO ASI 1600MM camera, Explore Scientific ED127 apo refractor, EQ6-R Pro mount Exposure: 160 x 90” L, 25 x 120” RGB Software: NINA, PixInsight Mukund’s top tips: “I saw the biggest improvement in my imaging when I started to consider pixel size and matching my image…

Short focus refractors have definitely made their mark, becoming very popular in recent years, and the new RVO Horizon 72ED is set to join them. The improved performance of such refractors makes them easy to use, quick and simple to mount and ideal for transporting to find better skies, whether it’s for foreign travel or to a nearby dark-sky site. Although far-off travel has been difficult in recent times, this had little impact on our tests because we had the refractor during one of the longest periods of clear skies we can remember. The Horizon 72ED, produced by Rotherham-based Rother Valley Optics, has a 72mm objective doublet lens with a focal length of 432mm, giving a focal ratio of f/6. The doublet is composed of FPL-53 glass, an extra-low dispersion…