DOCSLIB.ORG

Astrophotography: a Beginners Progress

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Astrophotography: a Beginners Progress ASTROPHOTOGRAPHY: A BEGINNERS PROGRESS ASTROPHOTOGRAPHY A BEGINNERS PROGRESS STEVE BALDWIN STEVE BALDWIN: WGCPC: 5th January 2016 1 ASTROPHOTOGRAPHY: A BEGINNERS PROGRESS INDEX: • Introduction • What is there to capture? • Where and when to take the images? • Planning • Equipment and settings (for imaging different astronomical subjects) • General equipment and settings issues • Dew formation • Post processing STEVE BALDWIN: WGCPC: 5th January 2016 2 ASTROPHOTOGRAPHY: A BEGINNERS PROGRESS Introduction: I have been taking photographs of the night sky since December 2012 after attending a short “Astrophotography for Beginners” course at the Royal Observatory in Greenwich. I am still a beginner –and this evening I hope to pass on some of what I have learnt so far and impart some of the enthusiasm I have for this genre of photography. But first a health warning: • It is not sociable – unless you are with like minded folk • It can involve a lot of driving • You can be waiting around in the dark for hours • It can be damned cold • It will result in severe loss of sleep • It can be extremely frustrating However, all of these are forgotten (but good to brag about) when you feel proud of a finished image! STEVE BALDWIN: WGCPC: 5th January 2016 3 ASTROPHOTOGRAPHY: A BEGINNERS PROGRESS Introduction (continued): Astrophotography can be spit into two main disciplines: • Photographs taken with a camera attached to a telescope. • Photographs taken with only a DSLR camera and tripod. The latter can be further categorised as either wide field or deep sky astrophotography. Deep sky astrophotography can be carried out with and without tracking, i.e. mounting the camera on a device which tracks the stars making corrections for the rotation of the earth. I do not own a telescope and whilst I now have a tracking mount this talk is about my attempts at taking images of the night sky using a static DSLR camera and a tripod, i.e. wide field astrophotography. Thus far, apart from specific applications i.e. star trails, my images are obtained without “stacking” in post processing. While the use of stacking is used in all forms of deep sky astrophotography it can be used as a means of capturing deep sky objects without the need for a tracking device and is a subject in itself –perhaps for another evening! STEVE BALDWIN: WGCPC: 5th January 2016 4 ASTROPHOTOGRAPHY: A BEGINNERS PROGRESS What is there to capture? There is a significant list of subjects that fall under the umbrella of astrophotography, not all of them visible after dark: • Lunar images *#% • Starscapes (landscapes taken after dark) and star trails *#% • Milky Way *#% • Planetary conjunctions *#% • ISS and satellites *#% • Meteor showers *# • Noctilucent clouds* • Aurora *# • Zodiacal light *# • Eclipses, both solar and lunar *# • Deep sky objects such as galaxies, comets and nebulae • Planetary transitions across the sun * * Images can be taken without stacking # Images I have attempted to date % Guidance on taking images is provided as part of this talk Subjects in italics are not strictly wide field astrophotography but are included for completeness. STEVE BALDWIN: WGCPC: 5th January 2016 5 ASTROPHOTOGRAPHY: A BEGINNERS PROGRESS Where and when to take the images? Astrophotography in general relies on having clear skies which in the UK can be problematical. I have been known to travel many miles to have the opportunity to capture specific astronomical events such as last years solar eclipse. Weather aside, we in the UK suffer from the effects of light pollution which often restricts our view of the night sky even when the sky is cloud free. So getting to a dark (or darker) sky site is important. An important aide in this quest is the Philips Dark Sky Map of Britain and Ireland available from bookshops and online resources such as the Dark Sky Discovery website at: http://www.darkskydiscovery.org.uk/ In the south east we have locations such as the Dengie peninsular in Essex (1.5hr drive) and the North Norfolk coast (2.5hr drive). Further afield the Purbeck peninsular in Dorset (3.5 hr drive) can provide magnificent views of the central band of our galaxy, the Milky Way. There are of course many other locations and dark sky parks such as those in the Northumberland and the Brecon Beacons National Parks which are more distant but well worth a visit. STEVE BALDWIN: WGCPC: 5th January 2016 6 ASTROPHOTOGRAPHY: A BEGINNERS PROGRESS Where and when to take the images? Philips Dark Sky Map of Britain and Ireland : STEVE BALDWIN: WGCPC: 5th January 2016 7 ASTROPHOTOGRAPHY: A BEGINNERS PROGRESS Where and when to take the images (continued)? The dark sky map is simple to read. The darker the colour of the overlay the darker the skies and the more stars that should be visible to the naked eye! The colours indicate the brightness of the dimmest star that can be seen with the naked eye at that location. The brightness scale can be confusing with the brightest objects having a –ve magnitude and the dimmest a +ve magnitude. The sun, the brightest object in the sky, has a brightness magnitude of ‐26.7, the full moon at ‐12.5, Venus, the brightest planet in our solar system at ‐4.4. When it comes to stars, Sirius A the brightest star in the sky has a magnitude of ‐1.5, Betelgeus, the star forming the right shoulder of Orion, has a brightness magnitude of 0.8 and the pole star, Polaris, a brightness magnitude of 2.1. In the centre of London the dimmest star that can be seen on a good day when away from street lights is of magnitude 3.7 whereas stars as dim as magnitude 6 can be observed with the naked eye in the darkest sky locations in the UK and Ireland. This is not a linear scale and the difference in brightness of these stars is a factor of 8, for those interested in the maths, (6.0‐3.7)2.5=8. STEVE BALDWIN: WGCPC: 5th January 2016 8 ASTROPHOTOGRAPHY: A BEGINNERS PROGRESS Where and when to take the images (continued)? Dark sky contours for the south east of England: STEVE BALDWIN: WGCPC: 5th January 2016 9 ASTROPHOTOGRAPHY: A BEGINNERS PROGRESS Where and where to take the images (continued)? Dark sky contours for the south west of Cornwall: STEVE BALDWIN: WGCPC: 5th January 2016 10 ASTROPHOTOGRAPHY: A BEGINNERS PROGRESS Where and when to take the images (continued)? Dark sky contours for the west of Ireland near Galway: STEVE BALDWIN: WGCPC: 5th January 2016 11 ASTROPHOTOGRAPHY: A BEGINNERS PROGRESS Where and when to take the images (continued)? Remember, once you get to a dark sky site give your eyes time to adjust. The dimmest stars visible at the chosen site will not be apparent for about 20 minutes after escaping from artificial light. So once at the selected dark sky site make sure you use a red torch to assist when setting up your gear –this will ensure that you preserve your night vision for the duration of the shoot. STEVE BALDWIN: WGCPC: 5th January 2016 12 ASTROPHOTOGRAPHY: A BEGINNERS PROGRESS Where and when to take the images (continued)? The dark sky contours provide guidance as to what you might see in a particular location if the viewing conditions are correct. The atmosphere is often clearest after heavy rain and when it has been windy. I have taken some of my best images of the moon this winter –every cloud has a silver lining! It is also often better to image the moon when it is high in the sky as this limits the amount of the earths atmosphere that you have to shoot through. STEVE BALDWIN: WGCPC: 5th January 2016 13 ASTROPHOTOGRAPHY: A BEGINNERS PROGRESS Planning? Planning is one of the most important aspects of successful astrophotography and there are many aides to assist the photographer: • Planetarium software such as Stellarium which is free to download at: http://www.stellarium.org/en_GB/ • Ordnance survey maps • Compass • Lunar phase calendar (available online, free) • Sunrise ‐ sunset calendar (available online, free) • Weather forecast ‐ Clear Outside at: https://clearoutside.com/forecast/51.82/‐0.10 • NASA website for sightings of the ISS (International Space Station) at: http://spotthestation.nasa.gov/ • Sightings of satellites including iridium flares at Heavens Above website: http://www.heavens‐above.com/ • Sky At Night Magazine –news on forthcoming astronomical events including monthly calendar of possible photographic opportunities STEVE BALDWIN: WGCPC: 5th January 2016 14 ASTROPHOTOGRAPHY: A BEGINNERS PROGRESS Planning (continued)? Stellarium screen capture showing planetary conjunction last October: STEVE BALDWIN: WGCPC: 5th January 2016 15 ASTROPHOTOGRAPHY: A BEGINNERS PROGRESS Equipment and Settings ‐ Lunar Photography: Let us start with Lunar photography. Equipment you will need to get started is little more than you will need for other photography genres: • DSLR camera with manual mode option • Tripod • Cable release Photographs of the lunar surface can be taken with a moderate telephoto lens. I use a 100‐400mm lens at 400mm on a full frame Canon camera but have also achieved reasonable results with a 300mm lens on a camera with an APS‐C cropped sensor. STEVE BALDWIN: WGCPC: 5th January 2016 16 ASTROPHOTOGRAPHY: A BEGINNERS PROGRESS Equipment and Settings ‐ Lunar Photography (continued): The moon is a bright object and hence an shutter speed of between 1/125s and 1/250s and f8 at ISO between 200 and 400 would be a good starting point depending on the moon phase. Remember to bracket your exposure. The moon is generally bright enough that your auto focus should still work. Remember to set your Autofocus mode to single point and ensure that the selected point is located over the surface of the moon.
Load more

Recommended publications
  • Noise and ISO CS 178, Spring 2014
    Noise and ISO CS 178, Spring 2014 Marc Levoy Computer Science Department Stanford University Outline ✦ examples of camera sensor noise • don’t confuse it with JPEG compression artifacts ✦ probability, mean, variance, signal-to-noise ratio (SNR) ✦ laundry list of noise sources • photon shot noise, dark current, hot pixels, fixed pattern noise, read noise ✦ SNR (again), dynamic range (DR), bits per pixel ✦ ISO ✦ denoising • by aligning and averaging multiple shots • by image processing will be covered in a later lecture 2 © Marc Levoy Nokia N95 cell phone at dusk • 8×8 blocks are JPEG compression • unwanted sinusoidal patterns within each block are JPEG’s attempt to compress noisy pixels 3 © Marc Levoy Canon 5D II at dusk • ISO 6400 • f/4.0 • 1/13 sec • RAW w/o denoising 4 © Marc Levoy Canon 5D II at dusk • ISO 6400 • f/4.0 • 1/13 sec • RAW w/o denoising 5 © Marc Levoy Canon 5D II at dusk • ISO 6400 • f/4.0 • 1/13 sec 6 © Marc Levoy Photon shot noise ✦ the number of photons arriving during an exposure varies from exposure to exposure and from pixel to pixel, even if the scene is completely uniform ✦ this number is governed by the Poisson distribution 7 © Marc Levoy Poisson distribution ✦ expresses the probability that a certain number of events will occur during an interval of time ✦ applicable to events that occur • with a known average rate, and • independently of the time since the last event ✦ if on average λ events occur in an interval of time, the probability p that k events occur instead is λ ke−λ p(k;λ) = probability k! density function 8 © Marc Levoy Mean and variance ✦ the mean of a probability density function p(x) is µ = ∫ x p(x)dx ✦ the variance of a probability density function p(x) is σ 2 = ∫ (x − µ)2 p(x)dx ✦ the mean and variance of the Poisson distribution are µ = λ σ 2 = λ ✦ the standard deviation is σ = λ Deviation grows slower than the average.
    [Show full text]
  • Depth of Field PDF Only
    Depth of Field for Digital Images Robin D. Myers Better Light, Inc. In the days before digital images, before the advent of roll film, photography was accomplished with photosensitive emulsions spread on glass plates. After processing and drying the glass negative, it was contact printed onto photosensitive paper to produce the final print. The size of the final print was the same size as the negative. During this period some of the foundational work into the science of photography was performed. One of the concepts developed was the circle of confusion. Contact prints are usually small enough that they are normally viewed at a distance of approximately 250 millimeters (about 10 inches). At this distance the human eye can resolve a detail that occupies an angle of about 1 arc minute. The eye cannot see a difference between a blurred circle and a sharp edged circle that just fills this small angle at this viewing distance. The diameter of this circle is called the circle of confusion. Converting the diameter of this circle into a size measurement, we get about 0.1 millimeters. If we assume a standard print size of 8 by 10 inches (about 200 mm by 250 mm) and divide this by the circle of confusion then an 8x10 print would represent about 2000x2500 smallest discernible points. If these points are equated to their equivalence in digital pixels, then the resolution of a 8x10 print would be about 2000x2500 pixels or about 250 pixels per inch (100 pixels per centimeter). The circle of confusion used for 4x5 film has traditionally been that of a contact print viewed at the standard 250 mm viewing distance.
    [Show full text]
  • Making Your Own Astronomical Camera by Susan Kern and Don Mccarthy
    www.astrosociety.org/uitc No. 50 - Spring 2000 © 2000, Astronomical Society of the Pacific, 390 Ashton Avenue, San Francisco, CA 94112. Making Your Own Astronomical Camera by Susan Kern and Don McCarthy An Education in Optics Dissect & Modify the Camera Loading the Film Turning the Camera Skyward Tracking the Sky Astronomy Camp for All Ages For More Information People are fascinated by the night sky. By patiently watching, one can observe many astronomical and atmospheric phenomena, yet the permanent recording of such phenomena usually belongs to serious amateur astronomers using moderately expensive, 35-mm cameras and to scientists using modern telescopic equipment. At the University of Arizona's Astronomy Camps, we dissect, modify, and reload disposed "One- Time Use" cameras to allow students to study engineering principles and to photograph the night sky. Elementary school students from Silverwood School in Washington state work with their modified One-Time Use cameras during Astronomy Camp. Photo courtesy of the authors. Today's disposable cameras are a marvel of technology, wonderfully suited to a variety of educational activities. Discarded plastic cameras are free from camera stores. Students from junior high through graduate school can benefit from analyzing the cameras' optics, mechanisms, electronics, light sources, manufacturing techniques, and economics. Some of these educational features were recently described by Gene Byrd and Mark Graham in their article in the Physics Teacher, "Camera and Telescope Free-for-All!" (1999, vol. 37, p. 547). Here we elaborate on the cameras' optical properties and show how to modify and reload one for astrophotography. An Education in Optics The "One-Time Use" cameras contain at least six interesting optical components.
    [Show full text]
  • Name: NAAP – the Rotating Sky 1/11
    Name: The Rotating Sky – Student Guide I. Background Information Work through the explanatory material on The Observer, Two Systems – Celestial, Horizon, the Paths of Stars, and Bands in the Sky. All of the concepts that are covered in these pages are used in the Rotating Sky Explorer and will be explored more fully there. II. Introduction to the Rotating Sky Simulator • Open the Rotating Sky Explorer The Rotating Sky Explorer consists of a flat map of the Earth, Celestial Sphere, and a Horizon Diagram that are linked together. The explanations below will help you fully explore the capabilities of the simulator. • You may click and drag either the celestial sphere or the horizon diagram to change your perspective. • A flat map of the earth is found in the lower left which allows one to control the location of the observer on the Earth. You may either drag the map cursor to specify a location, type in values for the latitude and longitude directly, or use the arrow keys to make adjustments in 5° increments. You should practice dragging the observer to a few locations (North Pole, intersection of the Prime Meridian and the Tropic of Capricorn, etc.). • Note how the Earth Map, Celestial Sphere, and Horizon Diagram are linked together. Grab the map cursor and slowly drag it back and forth vertically changing the observer’s latitude. Note how the observer’s location is reflected on the Earth at the center of the Celestial Sphere (this may occur on the back side of the earth out of view). • Continue changing the observer’s latitude and note how this is reflected on the horizon diagram.
    [Show full text]
  • Depth of Focus (DOF)
    Erect Image Depth of Focus (DOF) unit: mm Also known as ‘depth of field’, this is the distance (measured in the An image in which the orientations of left, right, top, bottom and direction of the optical axis) between the two planes which define the moving directions are the same as those of a workpiece on the limits of acceptable image sharpness when the microscope is focused workstage. PG on an object. As the numerical aperture (NA) increases, the depth of 46 focus becomes shallower, as shown by the expression below: λ DOF = λ = 0.55µm is often used as the reference wavelength 2·(NA)2 Field number (FN), real field of view, and monitor display magnification unit: mm Example: For an M Plan Apo 100X lens (NA = 0.7) The depth of focus of this objective is The observation range of the sample surface is determined by the diameter of the eyepiece’s field stop. The value of this diameter in 0.55µm = 0.6µm 2 x 0.72 millimeters is called the field number (FN). In contrast, the real field of view is the range on the workpiece surface when actually magnified and observed with the objective lens. Bright-field Illumination and Dark-field Illumination The real field of view can be calculated with the following formula: In brightfield illumination a full cone of light is focused by the objective on the specimen surface. This is the normal mode of viewing with an (1) The range of the workpiece that can be observed with the optical microscope. With darkfield illumination, the inner area of the microscope (diameter) light cone is blocked so that the surface is only illuminated by light FN of eyepiece Real field of view = from an oblique angle.
    [Show full text]
  • Low-Cost Computational Astrophotography
    Low-cost Computational Astrophotography Joseph Yen Peter Bryan Electrical Engineering Electrical Engineering Stanford University Stanford University [email protected] [email protected] Abstract 2. Related Work When taking photographs of the night sky, long ex- Currently, most astrophotographers compensate for posure times help photographers observe many stars, the rotation of the earth by physically moving the cam- but the rotation of the earth results in long star streak era along with the earth. However, some attempts arcs about the celestial pole. An algorithm for re- have been made to remove this requirement. To accu- moving these star streaks and substituting accurately rately localize stars in streaked images, one researcher placed point-like stars is designed and implemented. has re-mapped the star streak to polar coordinates, so Images containing star streaks are transformed into that all stars will have the same point-spread function. ones with un-streaked starry skies while retaining This technique was designed for locating specific stars color and brightness information. The procedure is for the purpose of identifying specific stars, but will shown to work consistently on a 35-image dataset. be applicable for our purposes when removing star streaks [4]. Other factors besides streaking can cause quality degradation in star images, and attempts have 1. Introduction been made to correct this. These have used such tech- niques as Richardson-Lucy deblurring [2] and maxi- Astrophotography is a widespread pastime in which mally sparse optimization [1]. DSLR cameras are used to take images of objects in space. Certain factors make this a very expen- sive hobby.
    [Show full text]
  • The Definitive Guide to Shooting Hypnotic Star Trails
    The Definitive Guide to Shooting Hypnotic Star Trails www.photopills.com Mark Gee proves everyone can take contagious images 1 Feel free to share this eBook © PhotoPills December 2016 Never Stop Learning A Guide to the Best Meteor Showers in 2016: When, Where and How to Shoot Them How To Shoot Truly Contagious Milky Way Pictures Understanding Golden Hour, Blue Hour and Twilights 7 Tips to Make the Next Supermoon Shine in Your Photos MORE TUTORIALS AT PHOTOPILLS.COM/ACADEMY Understanding How To Plan the Azimuth and Milky Way Using Elevation The Augmented Reality How to find How To Plan The moonrises and Next Full Moon moonsets PhotoPills Awards Get your photos featured and win $6,600 in cash prizes Learn more+ Join PhotoPillers from around the world for a 7 fun-filled days of learning and adventure in the island of light! Learn More Index introduction 1 Quick answers to key Star Trails questions 2 The 21 Star Trails images you must shoot before you die 3 The principles behind your idea generation (or diverge before you converge) 4 The 6 key Star Trails tips you should know before start brainstorming 5 The foreground makes the difference, go to an award-winning location 6 How to plan your Star Trails photo ideas for success 7 The best equipment for Star Trails photography (beginner, advanced and pro) 8 How to shoot single long exposure Star Trails 9 How to shoot multiple long exposure Star Trails (image stacking) 10 The best star stacking software for Mac and PC (and how to use it step-by-step) 11 How to create a Star Trails vortex (or
    [Show full text]
  • DSLR Astrophotography They Say… Start with a Joke
    DSLR Astrophotography They say… start with a joke. DLSR Wide-field Astrophotography The Advantages It’s Relatively Inexpensive All you need is a DLSR camera …and a tripod You Don’t Need This! Nikon v.s. Canon Most DSLR astrophotographers use Canon cameras. Canon releases the details of the camera’s software. This allows the development of third party software, designed specifically for astrophotography. Nikon does not create a truly raw image A simple median blurring filter is always applied... removing many stars, as they are seen as noise. This prohibits precise image calibration. Some Nikons allow the “Mode 3” work around. Using Nikon’s Mode 3 Simply start the bulb time exposure and terminate it by turning off the camera. The camera sees this as a low-power warning and immediately saves the image without running the median blurring filter Testing For Mode 3 Availability Take a one-minute dark exposure in Mode 1. This is a raw image with “no noise reduction” selected. Take a one-minute Mode 3 dark exposure. If Mode 3 is available, that exposure will have noticeably more hot pixels and noise. For Starters… Keep It Simple Set the focus to infinity... before it’s dark Mount the camera on a sturdy tripod Use a wide angle lens (18mm is nice) Set the lens to its lowest f-stop Use the RAW image format, at the highest ISO setting Shoot 20-30 second exposures Take about five dark exposures (more on this later) …and you can get an image like this! Nikon D40X 18mm @ f/4 ISO 1600 Mode 1 4 30-Sec exposures 4 30-Sec darks After taking several Milky Way shots it may be time to get more adventurous.
    [Show full text]
  • A Guide to Smartphone Astrophotography National Aeronautics and Space Administration
    National Aeronautics and Space Administration A Guide to Smartphone Astrophotography National Aeronautics and Space Administration A Guide to Smartphone Astrophotography A Guide to Smartphone Astrophotography Dr. Sten Odenwald NASA Space Science Education Consortium Goddard Space Flight Center Greenbelt, Maryland Cover designs and editing by Abbey Interrante Cover illustrations Front: Aurora (Elizabeth Macdonald), moon (Spencer Collins), star trails (Donald Noor), Orion nebula (Christian Harris), solar eclipse (Christopher Jones), Milky Way (Shun-Chia Yang), satellite streaks (Stanislav Kaniansky),sunspot (Michael Seeboerger-Weichselbaum),sun dogs (Billy Heather). Back: Milky Way (Gabriel Clark) Two front cover designs are provided with this book. To conserve toner, begin document printing with the second cover. This product is supported by NASA under cooperative agreement number NNH15ZDA004C. [1] Table of Contents Introduction.................................................................................................................................................... 5 How to use this book ..................................................................................................................................... 9 1.0 Light Pollution ....................................................................................................................................... 12 2.0 Cameras ................................................................................................................................................
    [Show full text]
  • Samyang T-S 24Mm F/3.5 ED AS
    GEAR GEAR ON TEST: Samyang T-S 24mm f/3.5 ED AS UMC As the appeal of tilt-shift lenses continues to broaden, Samyang has unveiled a 24mm perspective-control optic in a range of popular fittings – and at a price that’s considerably lower than rivals from Nikon and Canon WORDS TERRY HOPE raditionally, tilt-shift lenses have been seen as specialist products, aimed at architectural T photographers wanting to correct converging verticals and product photographers seeking to maximise depth-of-field. The high price of such lenses reflects the low numbers sold, as well as the precision nature of their design and construction. But despite this, the tilt-shift lens seems to be undergoing something of a resurgence in popularity. This increasing appeal isn’t because photographers are shooting more architecture or box shots. It’s more down to the popularity of miniaturisation effects in landscapes, where such a tiny part of the frame is in focus that it appears as though you are looking at a scale model, rather than the real thing. It’s an effect that many hobbyist DSLRs, CSCs and compacts can generate digitally, and it’s straightforward to create in Photoshop too, but these digital recreations are just approximations. To get the real thing you’ll need to shoot with a tilt-shift lens. Up until now that would cost you over £1500, and when you consider the number of assignments you might shoot in a year using a tilt-shift lens, that’s not great value for money. Things are set to change, though, because there’s The optical quality of the lens is very good, and is a new kid on the block in the shape of the Samyang T-S testament to the reputation that Samyang is rapidly 24mm f/3.5 ED AS UMC, which has a street price of less gaining in the optics market.
    [Show full text]
  • The Rise and Fall of Astrophotography Dr
    Page2 GRIFFITH OBSERVER August The Rise and Fall of Astrophotography Dr. Joseph S.Tenn Department of Physics and Astronomy Sonoma State University Rohnert Park, California HONORABLE MENTION HUGHES GRIFFITH OBSERVER CONTEST 1987 Dr. Joe Tenn’s carefully crafted articles seem to be able to win a prize in the annual Hughes Aircraft Company Science Writing Contest any time he chooses to enter, and his students have occasionally won prizes, too. This heartens our outlook on higher education in America and provides interesting and unusual material for readers of this magazine. His last article, “Simon Newcomb, a Famous and Forgotten American Astronomer," appeared in the November, 1987, issue of the Griffith Observer, almost two years ago. It was saddled with several errors imposed by the editor, not the author, and we hope this time we have given Dr. Tenn’s most recent contribution more reliable preparation for print. His attention this time is fixed on the development of astrophotography. Onthe occasion of the January, 1987, American the first serious uses of chemical emulsions for Astronomical Society meeting in Pasadena, professional research. Less than fifty years earlier visiting astronomers were invited to tour the the first crude experiments suggested the Palomar Observatory. The five-meter telescope, possibility that astronomical information might be towering five stories above us, looked as imposing recorded photographically. as ever, although it had been in operation nearly four decades and was no longer the world's DaQUe"'9°iYPe$ largest. Astronomers were involved with photography The real surprise, to this visitor at least, was from its beginning. It was the French astronomer that the telescope is no longer used for photo- Francois Arago who made the first public graphy.
    [Show full text]
  • Backlighting
    Challenge #1 - Capture Light Bokeh Have you seen those beautiful little circles of colour and light in the background of photos? It’s called Bokeh and it comes from the Japanese word “boke” meaning blur. It’s so pretty and not only does it make a gorgeous backdrop for portraits, but it can be the subject in it’s own right too! It’s also one of the most fun aspects of learning photography, being able to capture your own lovely bokeh! And that’s what our first challenge is all about, Capturing Light Bokeh! And remember - just as I said in this video, the purpose of these challenges is NOT to take perfect photos the first time you try something new… it’s about looking for light, trying new techniques, and exploring your creativity to help you build your skills and motivate and inspire you. So lets have fun & I can’t wait to see your photos! Copyright 2017 - www.clicklovegrow.com How to Achieve Light Bokeh Light Bokeh is created when light reflects off, or through, a background; and is then captured with a wide open aperture of your lens. As light reflects differently off flat surfaces, you’re not likely to see this effect when using a plain wall, for example. Instead, you’ll see it when your background has a little texture, such as light reflecting off leaves in foliage of a garden, or wet grass… or when light is broken up when streaming through trees. Looking for Light One of the key take-aways for this challenge is to start paying attention to light & how you can capture it in photos… both to add interest and feeling to your portraits, but as a creative subject in it’s own right.
    [Show full text]