The stars follow their gradual southern arcs parallel to the terrain during this 90 minute exposure. The water is unusually high this season, catching and reflecting starlight during its freefall down to the valley floor, the long exposure creating a flowing river of mist not possible to capture during the bright daylight hours.
Spring comes late to this region. Snow was an obstacle to bringing equipment to this site, but once there, I could enjoy a solitude that amplified the sounds of the great lake. The beating of waves against the shore diminished through the evening as the temperature dropped and the water in this back bay was held captive and quiet beneath a thin ice glaze. Occasional cracks and “tinks” were heard as daytime puddles froze in their rock bowls.
This time exposure captures the stars traversing their east-west passage over the recently thawed waters of Lake Superior. Park security lamps are now the only light on the famous cliff, illuminating the distinctive shape of this former, but now dark, guardian beacon.
The constellation Orion is a distinctive pattern in the winter sky. Look for the three-star belt, with another three-star sword hanging from it. Here he is with some of his less visible friends. The large red arc is Barnard’s Loop, which encircles the Orion Nebula (lower of the two red areas) and the Horsehead and Flame Nebulas.
Betelgeuse is the red giant star at Orions shoulder, not to be confused with the circular red Rosette Nebula to the left. The bright blue star at the lower left is Sirius (the Dog Star), the brightest star in the sky, and sailing above it in the blue river of the winter Milky Way is the red wisp of the Seagull Nebula.
I had tried once before to get a nighttime picture of these modern-day generators, to complement my shot of a more traditional windmill. The proximity to the large population near San Francisco Bay fills the sky with light, and my previous pictures had been washed out. This time I was armed with a light pollution rejection filter and enough time to find this interesting composition. I rediscovered a characteristic of these filters- they are very angle-of-view sensitive.
El Capitan’s immense figure blocks my view of the north star Polaris. I can only guess where it should be based on the time and positions of other stars. A position in an open field in Yosemite Valley allows me to make this composition.
The moonless night meant that the only illumination was by starlight. The park is sufficiently remote to escape the light pollution from large cities, but not enough to avoid airplane traffic. The distinct dotted lines mark the strobe lights of distant flights, unknowingly adding their trails to those of the stars.
Yosemite National Park, 13 April 2002 Pentax 67 w 55mm lens at f/4, 2 hour exposure on Provia 400
I was given a hint that I should consider Yosemite Falls as a startrail target because the trail to it ran along a north-south path. I wasn’t brave enough to hike in the dark, but I did find a vantage point from across the valley that placed Polaris directly above the falls.
The moonless night meant that the only illumination was by starlight. The park is sufficiently remote to escape the light pollution from large cities, but not enough to avoid airplane traffic. To minimize them crossing the view, this exposure was done in the very early morning hours when all the airplanes have found their destinations and the only sound in the air was the distant rushing of water.
If you are interested in my occasional contributions to Thor’s Life-Notes, I invite you to follow along.
Colorimetric Veil Six frames from SBIG ST-10 CCD camera using red, green, blue, H-alpha, O-III, and H-beta filters on an Astrophysics 130mm f/6 refractor. Colorimetric and spatial processing was used to combine the frames into this final image. Collaboration with astrophotographer Mike Cook.
After the hiatus while I compiled my Nightscape Odyssey notes and photos, I now return to my longer term project: “Coffee Table Nightscapes”, a collection of photos acquired over the years, often on business trips or summertime travels. I don’t pretend to be a competitor to APOD, where you will find spectacular astronomical imagery each and every day; rather, this is a low key way to share a few pictures that I enjoyed taking, with people that may appreciate them.
I resume the series with this image that someone else took. The Veil Nebula is a striking object in the sky and a popular target for astrophotographers. The view in the eyepiece of the telescope shows a faint fuzzy gray wisp of cloud, but cameras record something else. I was curious about what its actual visual appearance would be, if we could actually see it in full color.
The Veil Nebula is a supernova remnant– a star exploded, casting off a shell of gas that expands outward. The gas is hot and ionized and emits light at characteristic wavelengths. Hydrogen glows red at a characteristic 656nm, and also a blue-green at 486nm. Ionized oxygen emits green-blue light at 501nm. Most pictures of the Veil show a bright red cloud because the red H-alpha light is easy to record on film and CCD sensors. It is a challenge to display the blue-green colors because it falls in the gap between the blue and green-sensitive layers of film, and other imaging systems.
Figuring out how to make an image that was “colorimetrically correct” took me down a particular path of color science that resulted in a paper presented at the annual Color Imaging Conference. This image was my primary example among others, that were featured in the poster presentation (scroll to the end to see them). If you are still not convinced, try getting through the full technical details published in the Journal of Imaging Science.
The pictures I will be subsequently sharing are not this technically demanding. Whether simple or complex, simply enjoy them for their visual and inspirational value.
If you are interested in my occasional contributions to Thor’s Life-Notes, I invite you to follow along.
A view to the southwest includes the Milky Way, a target for one of my tests, behind incoming clouds lit by city-glow. The observatory has visitors whose cars illuminate its shell.,
A mostly clear night, and a new lens to try out! A lens I was hoping to use to capture wide-angle views of the Milky Way, and of northern lights, should I ever be in a position to do so.
I headed to Baylor Park, which is the home of Eagle Lake Observatory, operated by my astronomy club. I wasn’t there to use its facilities (though others were). I just wanted a clear view of the sky outside the city, somewhere I could practice techniques for making timelapse sequences, preferably alone, where I could make mistakes without an audience.
When Management Graphics adapted their film recording technology to support motion picture film formats, it was quickly adopted by movie studios to bring special effects from their computer memory images on to film. There were some problems however, and one of the most serious was the difficulty in obtaining the full brightness range found in typical scenes, especially when they included lights—candle light, desk lamps, car headlights, streetlights. Any light source, even a glimpse through a window to the bright outdoors, would cause a large flare in the final film frames, washing out detail in the scene. Our customers complained, and we started down a path to research and solve the problem.
We understood what the fundamental issue was: halation, an effect caused by the glass faceplate of the cathode ray tube used for creating the image. The bright spot on the phosphor screen was internally reflected at the glass surface which then illuminated the phosphor coating. If phosphor were black, this would not be a problem, but phosphor coatings are white, as are most materials made of fine powder, and it resulted in this internal reflected light overexposing the film. In the absence of a black phosphor, there were few other ways to mitigate the halation effect.
An example of halation on a photographic film plate. The circular haloes and flare are apparent around the street lights in this 1910 image.
One of our customers was incorporating our film recorder into a full workstation system. Quantel, a company in Newberry, England, had become successful in the early years of digital video and was looking for a way to expand its editing tool offerings into the motion picture market. Quantel’s engineers understood the halation problem as well, but they didn’t want to rely on our figuring out a solution: they had an aggressive development schedule.
I’m occasionally asked about the Academy Award that my colleagues at Management Graphics received. It was during the early days of computer-generated special effects in motion pictures. A product I contributed to, the Solitaire Image Recorder, was selected as a technology advance worthy of the Academy’s Technical Achievement Award. These awards are delivered in a parallel ceremony to the one we are all familiar with. It features celebrities of a different kind: nerds.
This is the story of how my friend Rick Keeney ended up on that award stage. It has been adapted from his personal account and is a bit technical, but don’t let those details detract from the overall story line.
Rick Keeney, with the Academy Award for Technical Achievement, 1992.
Invention and Innovation
In the formative days of digital photographic imaging, output back to film was produced using specialized, often hand-built, image recorders that were difficult to align, calibrate, and keep running consistently. As one of the early companies in the business of building and selling graphics workstations, Management Graphics (MGI) recognized that the drawbacks of the available film recorders were limiting its workstation sales. MGI kicked off a development effort to build a film recorder that would be a robust and easy-to-use product.
