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  • richardmitnick 11:47 am on July 22, 2021 Permalink | Reply
    Tags: "A large tidal stream observed in the Sombrero galaxy", Amateur Astronomy, Astrophotography, , , , ,   

    From IAC Institute of Astrophysics of the Canary Islands [Instituto de Astrofísica de Canarias] (ES) : “A large tidal stream observed in the Sombrero galaxy” 

    Instituto de Astrofísica de Andalucía

    From IAC Institute of Astrophysics of the Canary Islands [Instituto de Astrofísica de Canarias] (ES)


    Sombrero galaxy. Credits: National Aeronautics Space Agency (US) and the Hubble Heritage Team (Space Telescope Science Institute (US)/ Association of Universities for Research in Astronomy (US) (US))

    According to the latest cosmological models, large spiral galaxies such as the Milky Way grew by absorbing smaller galaxies, by a sort of galactic cannibalism. Evidence for this is given by very large structures, the tidal stellar streams, which are observed around them, which are the remains of these satellite galaxies. But the full histories of the majority of these cases are hard to study, because these flows of stars are very faint, and only the remains of the most recent mergers have been detected.

    A study led by the Institute of Astrophysics of Andalusia [Instituto de Astrofísica de Andalucía] (ES), with the participation of the Institute of Astrophysics of the Canaries[Instituto de Astrofísica de Canarias] (ES), has made detailed observations of a large tidal flow around the Sombrero galaxy, whose strange morphology has still not been definitively explained. The results are published today in the journal MNRAS.

    The Sombrero galaxy (Messier 104) is a galaxy some thirty million light years away, which is part of the Local Supercluster (a group of galaxies which includes the Virgo cluster and the Local Group containing the Milky Way).

    It has roughly one third of the diameter of the Milky Way, and shows characteristics of both of the dominant types of galaxies in the Universe, the spirals and the ellipticals. It has spiral arms, and a very large bright central bulge, which makes it look like a hybrid of the two types.

    “Our motive for obtaining these very deep images of the Sombrero galaxy (Messier 104) was to look for the remains of its merger with a very massive galaxy. This possible collision was recently suggested on the basis of studies of the stellar population of its strange halo obtained with the Hubble Space Telescope”, says David Martínez-Delgado, a researcher at the IAA-CSIC and first author of the paper reporting the work.

    The observations with the Hubble, in 2020, showed that the halo, an extensive and faint region surrounding the Sombrero galaxy, shows many stars rich in metals, elements heavier than hydrogen and helium. This is a feature typical of new generations of stars, which are normally found in the discs of galaxies, and are quite unusual in galactic halos, which are populated by old stars. To explain their presence astronomers suggested what is known as “a wet merger”, a scenario in which a large elliptical galaxy is rejuvenated by large quantities of gas and dust from another massive galaxy, which went into the formation of the disc which we now observe.

    “In our images we have not found any evidence to support this hypothesis, although we cannot rule out that it could have happened several thousand million years ago, and the debris is completely dissipated by now -explains David Martínez-Delgado-. In our search we have in fact been able to trace for the first time the complete tidal stream which surrounds the disc of this galaxy, and our theoretical simulations have let us reconstruct its formation in the last three thousand million years, by cannibalism of a satellite dwarf galaxy”.

    “Observational techniques in present day Astrophysics need advanced image processing. Our modelling of the bright stars around the Sombrero galaxy, and at the same time of the halo light of the galaxy itself has enabled us to unveil the nature of this tidal stream. It is remarkable that thanks to these advanced photometric techniques we have been able to do front line science with a Messier object using only an 18 cm (diameter) telescope”, explains Javier Román, a postdoctoral researcher at the IAC and a co-author of the study.

    The research team rejects the idea that the large stellar tidal stream, known for more than three decades, could be related to the event which produced the strange morphology of the Sombrero galaxy which, if it was caused by a wet merger, would need the interaction of two galaxies with large masses.

    The work has been possible thanks to the collaboration between professional and amateur astronomers. “We have collaborated with the Spanish astrophotographer Manuel Jiménez, who took the images with a robotic telescope of 18 centimetre diameter, and the well-known australian astrophotographer David Malin, who discovered this tidal stream on photographic plates taken in the 90’s of the last century. This collaboration shows the potential of amateur telescopes to take deep images of nearby galaxies which give important clues about the process of their assembly which is continuing until the present epoch”, concludes Martínez-Delgado.

    See the full article here .


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    IAC Institute of Astrophysics of the Canary Islands [Instituto de Astrofísica de Canarias] (ES) operates two astronomical observatories in the Canary Islands:

    Roque de los Muchachos Observatory on La Palma
    Teide Observatory on Tenerife.

    The seeing statistics at ORM make it the second-best location for optical and infrared astronomy in the Northern Hemisphere, after Mauna Kea Observatory Hawaii (US).

    Maunakea Observatories Hawai’i (US) altitude 4,213 m (13,822 ft)

    The site also has some of the most extensive astronomical facilities in the Northern Hemisphere; its fleet of telescopes includes the 10.4 m Gran Telescopio Canarias, the world’s largest single-aperture optical telescope as of July 2009, the William Herschel Telescope (second largest in Europe), and the adaptive optics corrected Swedish 1-m Solar Telescope.

    Gran Telescopio Canarias [Instituto de Astrofísica de Canarias ](ES) sited on a volcanic peak 2,267 metres (7,438 ft) above sea level.

    The observatory was established in 1985, after 15 years of international work and cooperation of several countries with the Spanish island hosting many telescopes from Britain, The Netherlands, Spain, and other countries. The island provided better seeing conditions for the telescopes that had been moved to Herstmonceux by the Royal Greenwich Observatory, including the 98 inch aperture Isaac Newton Telescope (the largest reflector in Europe at that time). When it was moved to the island it was upgraded to a 100-inch (2.54 meter), and many even larger telescopes from various nations would be hosted there.

    Teide Observatory [Observatorio del Teide], IAU code 954, is an astronomical observatory on Mount Teide at 2,390 metres (7,840 ft), located on Tenerife, Spain. It has been operated by the Instituto de Astrofísica de Canarias since its inauguration in 1964. It became one of the first major international observatories, attracting telescopes from different countries around the world because of the good astronomical seeing conditions. Later the emphasis for optical telescopes shifted more towards Roque de los Muchachos Observatory on La Palma.

  • richardmitnick 11:48 am on May 29, 2021 Permalink | Reply
    Tags: "Dark Frames and Bias Frames Demystified", A “bias frame” is an image taken with no light falling on the image sensor using the shortest exposure time you can manage with your camera., A “dark frame” is like a bias frame in that it's an image taken with no light falling on the image sensor but dark frames need to be the same length as your light frames., Astrophotography, If you use a master dark frame you don’t need a master bias frame — you really don’t want to subtract the dark fixed-pattern twice!, Image calibration is the first step of post processing., Many imagers skip calibration completely and some do it improperly., One of the keys to facilitating image post processing is to record better data in the first place., , Technological developments may eventually make dark frames obsolete., We use three different kinds of master calibration frames. You’ve probably heard of them: bias; darks; and flats.   

    From Sky & Telescope : “Dark Frames and Bias Frames Demystified” 

    From Sky & Telescope

    May 24, 2021
    Richard S. Wright Jr.

    “One of the keys to facilitating image post processing is to record better data in the first place. I’ve already talked a lot about fundamental techniques to help you capture the best data possible and understand the limits of your equipment or the weather. Once you’ve collected your images though, you need to calibrate them to obtain the best results.

    There is nothing wrong with your camera. Proper calibration is always needed for low light images.
    Credit: Richard S. Wright Jr.

    Image calibration is the first step of post processing, and when it’s done right it makes subsequent adjustments easier. Calibration helps remove artifacts that come with the image-acquisition process, so that your post processing deals with the actual good data you have worked so hard to acquire. Image calibration is also called data reduction, because it reduces all that you have collected to just the “data” part.

    Many imagers skip calibration completely and some do it improperly. Skipping a step can cost you time and effort later, and doing it improperly can make your initial starting point even worse than not doing it at all. Once images are clean, they require only minimal processing and produce stunning, informative, and honest images.

    This is simulated, but I’ve seen worse. Faint signal stretched hard will bring out your sensor’s dark fixed-pattern noise. Proper calibration can help a great deal with this. Credit: Richard S. Wright Jr.

    To remove the artifacts of the camera and optical system from our data, we use three different kinds of master calibration frames. You’ve probably heard of them: bias, darks, and flats. Flats are important enough to get a blog all their own, so this month I’m going to focus on biases and darks.

    Bias Frames

    A bias frame is an image taken with no light falling on the image sensor, using the shortest exposure time you can manage with your camera. Either close the shutter or cap your telescope. Bias frames should be recorded at the same temperature as your light frames (the actual exposure of your target), and using all the same camera gain or ISO settings.

    If you take your biases during the day, be careful that there are no light leaks getting to your sensor. Filter wheels and focusers often leak ambient light into your camera, which will ruin your bias frames. When I need to record bias frames during the day, I wrap much of the imaging train up with aluminum foil to keep this from happening.

    Bias frames capture dark fixed-pattern noise, shown here, from variations in manufacturing that affects all image sensors to some degree. Credit: Richard S. Wright Jr.

    Every image sensor, be it a CCD or CMOS, has what is known as dark fixed-pattern noise, a pattern that is the result of the manufacturing process. Every image you take records this faint pattern, no matter how long the exposure was or how much signal falls on your image sensor. The pattern then shows up in your images when you start to stretch (or brighten) the areas of your picture that collected little light.

    To remove dark fixed-pattern noise, subtract a bias calibration image from your light image. In order for this step to work well, a master bias frame is created by stacking many individual bias frames, which removes the read noise. You can subtract the master bias frame from any image you take with that camera, with whatever length exposure, as long as the other camera settings (temperature, gain, offset, etc.) are the same.

    Dark Frames

    A dark frame is like a bias frame in that it’s an image taken with no light falling on the image sensor, but dark frames need to be the same length as your light frames. In other words, if you take several 3-minute exposures on your target, you’ll want to calibrate them using a 3-minute master dark frame, which you’ll subtract from the image. This calibration step removes two things: First, your master dark contains the same dark fixed-pattern noise that your master bias frame does. It also collects dark current, and more pattern noise called DSNU (Dark Signal Non Uniformity). Individual dark frames also contain their associated shot noise with that comes along the dark current.

    If you use a master dark frame you don’t need a master bias frame — you really don’t want to subtract the dark fixed-pattern twice!

    The left image was recorded without cooling and suffers from excessive noise from the resulting dark current. Credit: Richard S. Wright Jr.

    The dark current comes from thermal activity (that is, heat) in the image sensor, and it creates a growing offset to all our pixel values that increases with both time and higher temperatures. If the effect were uniform we might not mind so much, but the offset is spread randomly among the pixels (the DSNU). The dark current also feeds “hot pixels” — pixels that appear much brighter than their neighbors. A good master dark can do a lot to remove that salty appearance from your raw frames. Cooling the sensor also greatly reduces the thermal current that pollutes images.

    We can’t simply subtract the shot noise associated with dark current from the dark frame; instead, we have to stack dark frames to minimize the noise. That way, this random noise doesn’t pollute all the light frames that we’re calibrating. The dark current’s shot noise is also in our light frames, but we can only remove this noise by stacking lot of light frames. When we subtract a dark frame, we remove hot pixel offsets and the dark current offset, but we can’t subtract the dark current’s shot noise — stacking is the only way to remove shot noise of any kind.

    Hot pixels can detract from a monochrome or color image. There are many techniques for removing them, but dark frames are a good first defense. Credit: Richard S. Wright Jr.

    The Future

    So why talk about bias frames if all you really need is a dark frame? Because technological developments may eventually make dark frames obsolete. There are many newer image sensors with extremely low dark current when cooled sufficiently. I really hope this trend continues. Once cooled they may gain a single electron or less per pixel over long periods of time — even 20 minutes in one sensor I’ve tested.

    If the camera sensor has no appreciative dark current when cooled, you can apply bias frames to your data and skip doing darks all together. You may still get some hot pixels here and there with these cameras, but those are easily removed with a pixel map in post processing or by dithering your exposures and stacking with a rejection algorithm.

    Some CMOS sensors also actively drain off dark current as it accumulates. You can watch this happen by taking longer and longer dark frames and observing that no additional background signal accumulates, even at warm temperatures! Again, in these cases, a good clean bias frame is all you’ll really need, plus stacking plenty of individual exposures.

    Stay tuned: Next time I’m going to talk about the alchemy of flat-frame calibration and why often people have such a hard time getting them to work properly for them.”

    See the full article here .


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    Sky & Telescope, founded in 1941 by Charles A. Federer Jr. and Helen Spence Federer, has the largest, most experienced staff of any astronomy magazine in the world. Its editors are virtually all amateur or professional astronomers, and every one has built a telescope, written a book, done original research, developed a new product, or otherwise distinguished him or herself.

    Sky & Telescope magazine, now in its eighth decade, came about because of some happy accidents. Its earliest known ancestor was a four-page bulletin called The Amateur Astronomer, which was begun in 1929 by the Amateur Astronomers Association in New York City. Then, in 1935, the American Museum of Natural History opened its Hayden Planetarium and began to issue a monthly bulletin that became a full-size magazine called The Sky within a year. Under the editorship of Hans Christian Adamson, The Sky featured large illustrations and articles from astronomers all over the globe. It immediately absorbed The Amateur Astronomer.

    Despite initial success, by 1939 the planetarium found itself unable to continue financial support of The Sky. Charles A. Federer, who would become the dominant force behind Sky & Telescope, was then working as a lecturer at the planetarium. He was asked to take over publishing The Sky. Federer agreed and started an independent publishing corporation in New York.

    “Our first issue came out in January 1940,” he noted. “We dropped from 32 to 24 pages, used cheaper quality paper…but editorially we further defined the departments and tried to squeeze as much information as possible between the covers.” Federer was The Sky’s editor, and his wife, Helen, served as managing editor. In that January 1940 issue, they stated their goal: “We shall try to make the magazine meet the needs of amateur astronomy, so that amateur astronomers will come to regard it as essential to their pursuit, and professionals to consider it a worthwhile medium in which to bring their work before the public.”

  • richardmitnick 12:45 pm on April 21, 2018 Permalink | Reply
    Tags: , , Astrophotography, , , Christian Sasse, , ,   

    From EarthSky: “Milky Way spins across the sky” 



    April 16, 2018
    Deborah Byrd

    This composite – centered on celestial south – is made of images taken hourly from outside the dome of the Anglo-Australian Telescope at Siding Spring Observatory.

    Composite image by Christian Sasse.

    Christian Sasse emailed EarthSky on April 11, 2018, from Australia’s Siding Spring Observatory and wrote:

    “A spectacular night at the Anglo-Australian Telescope (3.9-meter [13-foot] mirror). This composite – made of images taken every hour from 7 p.m. until midnight – shows the apparent movement of the Milky Way across the sky. See Jupiter on the left, leaving a discrete trail as it moves towards the dome until midnight. Top is location of the celestial South Pole.”

    AAO Anglo Australian Telescope near Siding Spring, New South Wales, Australia, Altitude 1,100 m (3,600 ft)

    Siding Spring Mountain with Anglo-Australian Telescope dome visible near centre of image at an altitude of 1,165 m (3,822 ft)

    As you can see, Christian has a novel approach to acquiring photographic images of star trails. His images have been featured in National Geographic and Nature. His Ph.D. in optics has helped shape his photography. You can visit him on his Facebook page, or on YouTube, or on Twitter (@sassephoto).

    Article by Christian Sasse, originally published at his blog, The Cosmic Clock.

    The Earth rotates or spins on its axis about every 24 hours, causing an apparent movement of the stars overhead by about one-quarter of a degree per minute. If we leave a camera in a fixed position and point upwards, open the shutter in bulb mode and let the Earth rotate under the stars, we will create an image with star trails. Similarly we could take shorter exposures and superimpose (stack) the images with image processing software.

    Most images of star trails taken in the Northern Hemisphere show a pattern similar to the one below taken in Arches National Park, Utah, in spring of 2016.

    Star trails at Arches National Park via Christian Sasse

    Bottom line: Milky Way composite image by Christian Sasse.

    Read more about Christian Sasse’s photographic process: A novel approach to star trails

    See the full article here .

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    Deborah Byrd created the EarthSky radio series in 1991 and founded EarthSky.org in 1994. Today, she serves as Editor-in-Chief of this website. She has won a galaxy of awards from the broadcasting and science communities, including having an asteroid named 3505 Byrd in her honor. A science communicator and educator since 1976, Byrd believes in science as a force for good in the world and a vital tool for the 21st century. “Being an EarthSky editor is like hosting a big global party for cool nature-lovers,” she says.

  • richardmitnick 8:37 am on April 4, 2018 Permalink | Reply
    Tags: , Astrophotography, , , , GALÁCTICA,   

    From IAC: “GALÁCTICA: The largest photo of the Milky Way available on the web” 

    My work for IAC would not be possible without the help of Manu Garcia.

    Manu Garcia, a friend from IAC.

    The universe around us.
    Astronomy, everything you wanted to know about our local universe and never dared to ask.


    Instituto de Astrofísica de Canarias – IAC

    Apr. 3, 2018
    Miquel Serra-Ricart:
    922 605 750

    This FECYT-funded project of the Instituto de Astrofísica de Canarias (IAC) has produced the largest panoramic view of our galaxy without using professional telescopes.


      A digital reflex camera, a telephoto lens, and a night sky renowned worldwide for its quality and darkness. These are the ingredients of GALÁCTICA, an IAC project whose aim is to obtain a gigapan (a giant mosaic) of the Milky Way to be used for outreach. What makes it different from other similar maps of our galaxy is that this is the first time such a map has been produced without relying on the telescopes of large professional observatories.

      ‘Because of the exceptional atmospheric conditions of Teide Observatory, we were able to acquire high quality images,’ notes Doctor Miquel Serra Ricart, the project’s coordinator, as well as being Manager of the Teide Observatory and an IAC researcher. ‘We’re still analysing the final mosaic in search of small objects that we haven’t yet labelled,’ he adds.

      For a year, with a digital camera equipped with a telephoto lens, the team obtained the images that make up the final gigapan. The team has also published 50 images at high resolution of the main objects that form part of our galaxy’s fauna. Serra and his team are, ‘Very enthusiastic about the second part of the project, which take us to the dark skies of Namibia from where we shall complete GALÁCTICA.’

      Instrumentation and observing procedure

      A DSLR full-frame camera (a modified SONY A7S) equipped with a fast telephoto lens (Canon 200 mm f/1.8)was used to build up the panorama. A second camera, a modified SONY A7S (with a 400 mm f/2.8 telephoto lens) was used at the same time to make high resolution observations of 50 objects that form part of the galactic fauna catalogue.

      The two cameras mounted in tracking mode on the Open Outreach Telescope (Telescopio Abierto Divulgación, TAD).

      Open Outreach Telescope Telescopio Abierto Divulgación TAD on Mount Teide at 2,390 metres (7,840 ft), located on Tenerife, Spain.

      This robotic telescope is equipped with a Losmany Titan equatorial mount to compensate for motion caused by the Earth’s rotation and is located at Teide Observatory (Izaña, Tenerife)

      Teide Observatory in Tenerife Spain, home of two 40 cm LCO,telescopes, Altitude 2,390 m (7,840 ft)

      A total of seven months was dedicated to the work, and observations were made only on nights close to new moon. This required 50 nights’ observing, in which 186 hours were needed to produce the panoramic view and 50 hours for galactic fauna objects. The images acquired so far cover 70% of the Milky Way, from the molecular cloud complex of Orion to Antares in the constellation Scorpius. During the second half of 2018, the GALACTICA-S project, funded by FECYT, will map the remaining 30% of our galaxy.

      The GALÁCTICA project has been funded by the Fundación Española para la Ciencia y la Tecnología (FECYT) of Spain’s Ministry of Economy, Industry and Competitiveness.

      The IAC Observatories form part of Spain’s network of Special Scientific and Technical Infrastructures (Infraestructuras Científicas y Técnicas Singulares, ICTS).

      See the full article here.

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      The Instituto de Astrofísica de Canarias(IAC) is an international research centre in Spain which comprises:

      The Instituto de Astrofísica, the headquarters, which is in La Laguna (Tenerife).
      The Centro de Astrofísica en La Palma (CALP)
      The Observatorio del Teide (OT), in Izaña (Tenerife).
      The Observatorio del Roque de los Muchachos (ORM), in Garafía (La Palma).

      Roque de los Muchachos Observatory is an astronomical observatory located in the municipality of Garafía on the island of La Palma in the Canary Islands, at an altitude of 2,396 m (7,861 ft)

      These centres, with all the facilities they bring together, make up the European Northern Observatory(ENO).

      The IAC is constituted administratively as a Public Consortium, created by statute in 1982, with involvement from the Spanish Government, the Government of the Canary Islands, the University of La Laguna and Spain’s Science Research Council (CSIC).

      The International Scientific Committee (CCI) manages participation in the observatories by institutions from other countries. A Time Allocation Committee (CAT) allocates the observing time reserved for Spain at the telescopes in the IAC’s observatories.

      The exceptional quality of the sky over the Canaries for astronomical observations is protected by law. The IAC’s Sky Quality Protection Office (OTPC) regulates the application of the law and its Sky Quality Group continuously monitors the parameters that define observing quality at the IAC Observatories.

      The IAC’s research programme includes astrophysical research and technological development projects.

      The IAC is also involved in researcher training, university teaching and outreachactivities.

      The IAC has devoted much energy to developing technology for the design and construction of a large 10.4 metre diameter telescope, the ( Gran Telescopio CANARIAS, GTC), which is sited at the Observatorio del Roque de los Muchachos.

      Gran Telescopio Canarias at the Roque de los Muchachos Observatory on the island of La Palma, in the Canaries, SpainGran Telescopio CANARIAS, GTC

  • richardmitnick 12:23 pm on October 7, 2017 Permalink | Reply
    Tags: , Astrophotography, , , , , Shooting star   

    From ESA: “Shooting star” 

    ESA Space For Europe Banner

    European Space Agency

    Shooting star
    Copyright K. Miskotte

    A bright fireball was spotted over the Netherlands and Belgium on 21 September at 21:00 CEST (19:00 GMT).

    It was caused by a small meteoroid, estimated to be around several centimetres, entering Earth’s atmosphere and burning up.

    The fireball was captured by a number of all-sky camera stations of the Dutch–Belgian meteor network operated by amateurs of the Dutch Meteor Society and the Meteor Section of the Royal Netherlands Association for Meteorology and Astronomy. They use automated photographic cameras with fish-eye lenses to capture images of the night sky on clear nights.

    This remarkable image was captured by one of the stations, at Ermelo, operated by Koen Miskotte.

    It is a 1.5 minute exposure with a Canon EOS 6D DSLR and a fish-eye lens.

    The camera lens was equipped with an LCD shutter that, during the exposure, creates brief ‘breaks’ at a rate of 14 per second. These are the dark gaps in the trail making it look dashed. Because the LCD shutter rate is known, you can count the dashes and obtain the duration of the fireball: 5.3 seconds.

    The image also provides information on the deceleration of the meteoroid in the atmosphere. In this case, it entered the atmosphere at 31 km/s and had slowed to 23 km/s by the time it disappeared (because it had burnt up completely) at 53 km altitude.

    The bright star trail just below the tip of the fireball is Arcturus. The Big Dipper can be seen at right, above the treeline. The bright star near the centre of the image just left of the fireball trail is Vega.

    Read full details on this brief but fiery event via Marco Langbroek’s SatTrackCam blog.

    More information


    See the full article here .

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    The European Space Agency (ESA), established in 1975, is an intergovernmental organization dedicated to the exploration of space, currently with 19 member states. Headquartered in Paris, ESA has a staff of more than 2,000. ESA’s space flight program includes human spaceflight, mainly through the participation in the International Space Station program, the launch and operations of unmanned exploration missions to other planets and the Moon, Earth observation, science, telecommunication as well as maintaining a major spaceport, the Guiana Space Centre at Kourou, French Guiana, and designing launch vehicles. ESA science missions are based at ESTEC in Noordwijk, Netherlands, Earth Observation missions at ESRIN in Frascati, Italy, ESA Mission Control (ESOC) is in Darmstadt, Germany, the European Astronaut Centre (EAC) that trains astronauts for future missions is situated in Cologne, Germany, and the European Space Astronomy Centre is located in Villanueva de la Cañada, Spain.

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  • richardmitnick 3:56 pm on May 15, 2017 Permalink | Reply
    Tags: Astrophotography, , SASSEPHOTO, See the Awesome March of the Milky Way Across the Night Sky,   

    From natgeo.com: “See the Awesome March of the Milky Way Across the Night Sky” 

    National Geographic

    National Geographics

    15 May 2017
    Nadia Drake

    A photographer captures rare views of the galaxy as it spirals over southern Australia.

    High overhead, the Milky Way galaxy twists itself into a whirling pinwheel, its glittering stars and dense, dark clouds weaving spirals on the sky.

    At least, that’s the view photographer Christian Sasse revealed when he shared this image of the nighttime sky over southern Australia. Seen from Earth’s vantage point in one arm of the Milky Way, our galaxy appears to dive through the cosmos, its curling spine anchored to the sky by the southern celestial pole — one of the points around which the stars and all their minions appear to wander as Earth spins on its axis.

    Time: 10 minutes

    Time: 120 minutes

    Sasse made the image he shared on Twitter from a series of 30-second-long exposures, each taken 50 minutes apart, over 10 hours on April 28. He stacked those photographs using Startrails software and then edited the final composite image using Photoshop.

    “The southern sky is fascinating in so many ways,” says Sasse, who set up his gear near one of the telescopes at Siding Spring Observatory in New South Wales.

    Siding Spring, near Coonabarabran, New South Wales, Australia

    AAO 1.2m UK Schmidt Telescope at Siding Spring Observatory, near Coonabarabran, New South Wales, Australia

    ANU Skymapper telescope, a fully automated 1.35 m (4.4 ft) wide-angle optical telescope, at Siding Spring Observatory , near Coonabarabran, New South Wales, Australia

    Siding Spring Observatory, near Coonabarabran, New South Wales, Australia

    “I remember hearing the dome roaring deeply all night whenever the telescope moved from object to object.”

    Based in Vancouver, Sasse had travelled to Australia to visit a friend. He rented a small camper van, decked out its interior with the gadgets he’d need to capture both wildlife and the glorious southern sky, and headed out to a spot where “the skies are pristine and you can be all on your own at night … often accompanied by curious kangaroos.”

    Indeed, some of the most notable treasures in the immediate cosmic neighborhood are visible primarily in the south: Alpha Centauri, the nearest star system to our own, the bright star grouping known as the Southern Cross, a dark blotch called the Coalsack Nebula, small satellite galaxies known as the Large and Small Magellanic Clouds, and the glowing backbone of the Milky Way.

    “In the Northern hemisphere, I tend to look South, and in the Southern hemisphere — well, I also look South,” says Sasse, who captured those curiosities in the great looping footprint he constructed.

    Photographers often use a similar technique to create images depicting stars tracing circles around the celestial poles. Sasse initially did the same thing, stitching together roughly 1,250 images from the same night. But when he smeared the stars into circles, Sasse saw that our home galaxy had vanished, taking with it some of the most striking textures in the sky.

    So he experimented with layering images taken at different intervals (see gallery), and was astounded by the result.

    “What appeared were circular patterns with intrinsic beauty. Each feature of the Milky Way has its own distinct pattern, and details became finer the closer one moved to the pole,” Sasse says. “The Milky Way is creating this incredible pattern all the time, and the way we freeze it is the way we like it.”

    I’ve been looking at the heavens all my life, and that great, milky spiral is unlike anything I’ve ever seen before — it reminds me of a galactic mandala, a demonstration of celestial geometry, an accidental fractal, a rippling kaleidoscope of stars.

    “I have a fascination with light patterns in nature — iridescence of birds and fish, feather structure of eagles, anything that changes with small angles such as diffraction and reflection,” says Sasse, who has a doctorate in optics.

    To me, it evokes a sense of awe and appreciation for the intricate patterns hiding in the skies, and a restless yearning to throw myself onto grass still warmed by the southern sun, snuggle in for a few hours, and stare into the twinkling tapestry that twirls overhead.


    See the full article here .

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    The National Geographic Society has been inspiring people to care about the planet since 1888. It is one of the largest nonprofit scientific and educational institutions in the world. Its interests include geography, archaeology and natural science, and the promotion of environmental and historical conservation.

  • richardmitnick 4:03 pm on April 24, 2017 Permalink | Reply
    Tags: , Astrophotography, , , ,   

    From Liverpool: “Shooting for the stars: capturing the beauty of science through astrophotography” 

    Liverpool John Moores University

    Thor’s Helmet is a planetary nebula. Nothing to do with planets, it is actually a shell of gas being thrown off from an old star towards the end of its life cycle. Planetary nebulae are wonderfully varied in shape and colour. This image was originally obtained with the Liverpool Telescope for BBC Sky At Night.

    2-metre Liverpool Telescope at La Palma in the Canary Islands

    Castell Alun High School captured the Messier 27 through the NSO.

    National Solar Observatory at Kitt Peak in Arizona

    One of the best planetary nebulae to observe on the NSO, it almost fills the field of view, providing a spectacular image with vast detail. The image was produced by combining observations in the blue, visual and red filters using NSO’s 3-colour image tool.

    The Crab Nebula is a supernova remnant, the expanding cloud of gas and dust from a catastrophically exploding star. Chinese astronomers witnessed this explosion in 1054 and we still see the remnant cloud now. To the human eye, it would be faint pink. Scientific instruments do not necessarily ‘see’ colours the same way as our eyes and allow astronomers to bring out details that a true colour image might not reveal.

    When thinking about the types of photographs that capture the beauty of science, a stunning landscape or an animal in its natural habitat might come to mind. But when it comes to images from telescopes, we might not immediately consider these as anything more than the collection of scientific data. Beyond their significance in helping us to discover more about our universe, the images of galaxies, planets and stars are also appreciated purely for aesthetic reasons. For many amateur and professional astrophotographers capturing the shapes and colours of the universe is just as important as capturing scientific data. In fact, most astronomical images for general viewing have been modified from their original form. An astrophotographer’s goal in this case is to bring out the best of the image – to find the art within the science.

    Robert Smith, creator of the “Iridis” image which won the Robotic Scope Special Prize at the Insight Astronomy Photographer of the Year competition, sums up the concept of science as art/art as science:

    “We often hear about the idea of representing scientific data in an appealing way as an expression of art, but why not look at it the other way around; ‘art as science’? Astrophotography is not just a matter of making science look pretty, it shows us that beauty actually is science. The winners of this competition were obviously selected because they were beautiful, striking or interesting, but each and every one is also an expression of astrophysical processes and could be the basis of a science seminar in their own right. It is physics that creates that beauty. Looking at the swirling gas in a nebula or the aurorae, you are literally seeing maths and physics.”

    Robert is an astronomer at the Astrophysics Research Institute (ARI) at LJMU and captured the award-winning image from ARI’s very own Liverpool Telescope. As the world’s largest fully robotic telescope, the Liverpool Telescope is responsible for a wide range of images which, in addition to their obvious importance scientifically, are also interesting and beautiful as pieces of art in their own right.

    Astronomers were among the first to embrace photography, with the first images of the sun captured on daguerreotypes, an early photographic imaging process, in the 1840s.

    Users of the Liverpool Telescope not only include researchers at LJMU but because it is remotely operated, it is available to astronomers from around the world. Schools and colleges across the UK and Ireland also get involved in capturing astronomical images. As a part of ARI’s educational outreach programmes, the National Schools’ Observatory (NSO) makes it possible for schoolchildren to study the night sky for themselves via the Telescope. Almost 4,000 schools have already participated with students making well over 100,000 astronomical observations from the classroom. A couple examples of the photos from NSO can be found on this page, but feel free to take a look at more on the NSO website.


    How do you photograph a night sky?

    Make sure it’s a clear night and find a place as far away from light pollution as you can. With a manual camera, try setting 25 second exposure, f/2.8, ISO 1600 (you can experiment with these settings). You’ll need a tripod to keep your camera stable during the exposure. Modern smartphones can produce impressive results as well. There are free apps available to download that automatically take a series of short exposures for you and add them together to create a long night-time photo.

    If you have access to a telescope, you can hold your smartphone up to the eyepiece of the telescope and take your shot, this is known as afocal photography – where the lens takes the place of the human eye.

    There are plenty of tips for getting started in astrophotography, just do a search online and you’ll be exposed to a wealth of information.

    See the full article here .

    Please help promote STEM in your local schools.

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    Stem Education Coalition


    Liverpool John Moores University is a public research university[6] in the city of Liverpool, England. It has 21,875 students, of which 18,375 are undergraduate students and 3,500 are postgraduate, making it the 33rd largest university in the UK by total student population.

    The university can trace its origins to the Liverpool Mechanics’ School of Arts, established in 1823 making it a contestant as the third-oldest university in England; this later merged to become Liverpool Polytechnic. In 1992, following an Act of Parliament the Liverpool Polytechnic became what is now Liverpool John Moores University.

    It is a member of the University Alliance, a mission group of British universities which was established in 2007.[9] and the European University Association.

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