A “blood moon” is the name given to a total lunar eclipse, due to its reddish color when in the Earth’s shadow. The title “supermoon” is given to a full moon when it is at its closest approach, making it appear a bit larger than average. When a lunar eclipse happens at this perigee, it may be called a super blood moon.
At totality, the moon is entirely inside the shadow of the Earth, although it might not be perfectly centered. The color is a dark orange, but not uniformly so. It is so dim that stars, normally washed out by the moon’s glare, can be seen in the background.
We can see the curvature of the Earth as the moon enters its shadow. The color in the shadow is a coppery red, but it is a thousandth of the brightness of the still-illuminated half.
It is rare for Venus to pass in front of the sun and so I assembled telescopes and equipment while Poldi hosted a picnic, inviting family and friends to view an event that won’t happen again for a hundred years. We spent the afternoon and evening watching the silhouette of Venus move slowly across the face of the sun until it dropped behind clouds and trees at sunset .
When the moon, in its monthly travel around Earth, moves across a bright star, it is called an occultation. On this date, the moon is moving toward the bright star Regulus. Here is a superposed series of pictures taken over 1 hour as Regulus apparently “approaches” and then is eclipsed by the moon.
3 November 2007 Takahashi CN212, Newtonian configuration, f/4 Canon EOS 20Da, ISO 800 1/500 sec, superposition of successive exposures, one minute apart.
In 2007 a comet passed through our neighborhood and allowed me a chance to try the high dynamic range (HDR) imaging techniques that were being developed at that time. The idea is to combine a range of exposures to get a large range of detail. In this case 10 exposures covering the range from 1 second to 8 minutes are combined, selecting the best tonal information from each. This allows the otherwise obscured ion cloud surrounding the dusty nucleus to become visible as a faint blue-green glow. I was able to use this image as an HDR example in a conference presentation I made on this topic the following week.
An early experiment in using different exposures to build a high dynamic range (HDR) image of the Orion Nebula. The “Running Man” nebula is revealed to its upper left.
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.
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.
