Third Tail

On April 8, a friend joined me to observe Hale-Bopp at my nearby and nearly-dark site at Lake Zumbra. We enjoyed watching the very young moon set, then went about preparing to take some pictures. I was hoping to get a shot taken at a smaller lens aperture so the stars would have less distortion than in my earlier photos. We were able to make three exposures of the comet. Two of the three showed a tracking problem: the weight shifted across the drive gear during the exposure. The result looked like a double exposure with every star appearing twice, once while the motor was “pushing” the gear, and again with the gear pulling the motor. The separation is a measure of the backlash in the system. Just another of the 1000 obstacles to taking pictures of the sky. Fortunately, one frame turned out. The stars are mostly quite sharp little points. Their relative colors also show up nicely. The comet itself has a broader dust tail than a week earlier; and the ion tail seems to have two parts! Is this the “invisible third tail”? The stars above Comet Hale-Bopp belong to the constellation Perseus. Just to the right of the comet’s head is a tight grouping of stars. This is M34, an open cluster, the 34th entry in the famous Messier list of “non-comet” objects. Lake Zumbra (Victoria MN), 9:00 pm 8 April 97. Kiev-88 80mm, 5 minutes at f/4 on PMC400.

Andromeda Galaxy

The Andromeda Galaxy spans a portion of the sky that is larger than the full moon! But a full moon would wash out the sky, making the galaxy hard to see, even with binoculars. When the sky is dark it can be seen as a hazy smudge, making it the most distant object (more than two million light years away) that we can see with the naked eye. In the eyepiece of a telescope the smudge becomes larger, but to detect the wonderful spiral structure and faint blue outer arms of this galaxy requires the light-accumulating power of a piece of film placed at the telescope’s focal point. The stars in this picture are in the foreground, artifacts from our own galaxy, which we must look through to see into our neighbor’s part of the universe. Cherry Grove Observing Site, MN 08 Oct 99 E200 Ektachrome, pushed +2 stops Superposition of two 20-minute exposures

Lunar Eclipse Sequence

I have seen a total lunar eclipse before, but it was by accident, and I was unable to successfully photograph it. This time I knew it was coming and the skies were clear, but the brutally cold temperatures caused me to find excuses to stay indoors. I was goaded into it however by my son, who pointed out that I had acquired considerable cold weather gear, equipment, and specialized clothing for my peculiar hobby. If not now, when would I ever put them to use? Of course to maintain any sense of pride, I quietly took his point and proceeded to set up in the neighborhood open area. It is directly under a streetlight which exposed my activities to the neighbors, whose curiosity was not deterred by the temperature. By the time the edge of the moon started to dim, a small group of kids and their hardy parents had assembled to see what would happen. Our informal eclipse party would last for the next few hours, with people cycling through neighboring houses, returning with hot chocolate, warmed-up feet, and more participants. My own schedule called for taking an exposure every ten minutes, not quite enough time to leave my post. It was enough time to explain what was happening and to show views though the telescope as the edge of the Earth's shadow crossed the face of the moon. I like to explain that if we were on the moon, the Earth would be backlit, and that everywhere along its edge is at either sunset or at sunrise. The sky there is familiar to us: red and orange, the colors refracted slightly around the Earth's edge by the air. It is this reddish-orange light source that illuminates the moon when the sun no longer hits it directly. It is interesting that the edge of the shadow shows a bit of brownish cast. As the last bit of direct sunlight hits the very edge of the moon, the orange-brown shadow details emerge. It has been there all along, but our eyes can now adapt to this much dimmer light level. These views are quite similar to the visual experience. At full totality however, the moon seemed to be a grayish brown color. The deep red in the photo is not artificial; the film sees it better than we do. Minnetonka MN 20 Jan 2000 First image 8:55 pm CST Nikon-F at prime focus of Takahashi CN-212 (Newtonian 820mm at f/3.9) E200 Ektachrome

Total Lunar Eclipse

If we were on the moon during a lunar eclipse, the Earth would be backlit, and everywhere along its edge is at either sunset or at sunrise. The sky there is familiar to us: red and orange, the colors refracted slightly around the Earth's edge by the air. It is this reddish-orange light source that illuminates the moon when the sun no longer hits it directly. This picture was taken during the midpoint of the eclipse when the moon was deepest in shadow. The visual appearance was a dim grayish brown, but a long enough exposure on film will show the red component to its color. The "bottom" of the moon is brighter. This means that the moon didn't pass through the dead center of the Earth's shadow, but toward one side. This view is similar to the visual experience. At full totality however, the moon seemed to be a grayish brown color. The deep red in the photo is not artificial; the film just sees it better than we do. 20 January 2000 10:55 pm CST, Minnetonka MN Nikon-F at prime focus of Takahashi CN-212 (Newtonian 820mm at f/3.9) 2 second exposure on E200 Ektachrome

Orion Nebula

On most winter nights, the distinctive constellation of Orion the Hunter is plainly visible in the southern sky. Orion sports a “belt” from which hangs a three-star “sword”. The Orion Nebula is the smudge of the middle star in Orion’s sword. A closer look at it reveals that it is not a star at all, but a group of stars shrouded in a cloud of dust and glowing gas. This is a stellar nursery where new stars are being formed. As the gas coalesces, it is energized and emits a characteristic red glow, not bright enough to be seen visually, but captured nicely on film. Cherry Grove Observing Site, MN 04 March 2000 E200 Ektachrome Superposition of two 10-minute exposures

North American Nebula

In the constellation Cygnus, (the Swan) is a large complex of glowing gas nebulas, and this portion has a shape suggestive of a familiar continent. The strong red color is easily recorded on film, but large telescopes and special filters are needed to make it visible to human night vision. The bright star on the left, "62-Cygni (xi)", dominates this picture, but if you were to look at the sky, it would not be particularly noticable among the dozen even brighter stars in this constellation! Cherry Grove Observing Site, MN 07 June 2000 Nikon-F at prime focus of Takahashi CN-212 (Newtonian 820mm at f/3.9)

Horsehead and Flame Nebula

This is a favorite target for astrophotographers. It's a famous image, but quite challenging to capture, partly because it is only visible during the winter months when Orion the Hunter is up. The weather conditions will always be cold, at least in the northern latitudes, and so winter gear is required. It is not easy to actually see this target. The nearby bright star, zeta Orionis, is a convenient marker, but its glare easily washes out the faint glow of the Horsehead and another nearby object just below zeta, the "Flame Nebula". Portage Lake, MN 25 Nov 2000 20-minutes at f/4 Kodak PJ400 color negative film, pushed 1 stop

Rosette Nebula

This is a very large region of sky, but the beautiful red remnants of this supernova explosion are faint. One of the attractive features of the Rosette is the cluster of stars at its center. One of these may be the star that expoded eons ago leaving this signature shell of expanding and glowing gas. Portage Lake, MN 25 Nov 2000

California Nebula

The large red glowing gas cloud shaped like the state of California. Grand Tetons National Park 16 August 2001

Colorimetric Veil

This picture was created by colorimetrically combining six frames obtained by Mike Cook into a calibrated color space. The hues and relative intensities indicate the colors we would see if our vision was sensitive enough to see color at these low light levels. 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 gree-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. 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.

Orion and Friends

The constellation Orion is a distinctive pattern in the winter sky. 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), and sailing above it in the blue river of the winter Milky Way is the red wisp of the Seagull Nebula. Lake Superior shoreline near Two Harbors, MN March 2004 Pentax 6x7, 55mm, f/5.6 E200 +2 stops, 20 minutes, guided

Orion Nebula HDR

An early experiment in using different exposures to build a high dynamic range image of the Orion Nebula. The "Running Man" nebula is revealed to its upper left. Monument Valley, Navaho Nation 5 November 2005 Televue 85 f/5.6 Canon EOS 20Da

Pleides

A close-up of the Seven Sisters. The wispy blue glow is from dust reflecting the light of these nearby stars. Monument Valley, Navaho Nation 5 November 2005 Televue 85 f/5.6 Canon EOS 20Da

Comet Holmes

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. 2 November 2007 Takahashi CN212 in Newtonian configuration (f/4) Canon EOS 20Da, ISO 800

Regulus Occultation

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 CN 212, Newtonian configuration, f/4 EOS 20Da, ISO 800 1/500 sec, superposition of successive exposures one minute apart

Comet Neowise

A photogenic comet visits in a year when the world is shut down by a virus. We can still appreciate its beauty and find an isolated area in a nearby park. Photographing comets has become considerably easier in the twenty years since my previous attempts trying to capture Comet Hale-Bopp on film!