6.3 Risky Exposures

Sentinal Point is one of the high spots on the crater rim, providing a commanding vista of nearly the entire caldera of the ancient volcano. I selected this location, a turnout that would mostly avoid oncoming traffic, to setup my equipment that night. I brought out the works, everything I had, telescope, sky tracking camera, and fixed tripods. I planned to take some prime focus deep sky pictures that evening, as well as some wide-angle views of the Milky Way. This meant polar aligning two mounts, which kept me busy until astronomical twilight, some two hours after sunset.

I also placed two fixed tripod cameras for startrail pictures. I spent quite a bit of time trying to find that photogenic angle that included sky, crater, lake, and the star groupings that I wanted to capture; there was just no vantage point that had a clear view. The withered pine trees that grew on the rim surface were just dense enough and sprawling enough, that they always intruded in my viewfinder. If I could just get down to that exposed rocky point on the rim wall, I could get my clear shot.  Of course, scrambling down the rim wall is highly discouraged. The barrier at the edge of the turnout is the limit of sanctioned range for tourists, and exploring beyond is prohibited.

Yet down there was the perch that I sought. While it was still light out, I ventured out onto the hybrid surface of rocky talus and weathered soil. A few plants held it together, and some tenacious trees had made outposts. I found a suitable location that contained my target view and planted the tripod. I setup the camera in preparation for later when it would be dark, and I could start the exposure.

Yes, later, when it would be dark. I wondered how I was going to find my camera later when it was dark. It was one degree of risk to climb out of bounds in daylight, another to do it in the dark.

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6.2 Crater Lake Rim Drive

I made a short agenda for myself:

  – set up camp 
  – catch up on some writing 
  – find tonight’s shooting site 
  – organize shooting targets, schedule 
– fix the broken connector on the battery holder for the Pentax camera
  – prepare, make coffee, organize car 
  – take nap

This was more than a full day’s work. I never got to take the nap, but I did drive all the way around the crater’s rim, checking out the various overlooks, trailheads, and picnic areas, evaluating each for their access, orientation, and opportunities for interesting nighttime landscapes.

The wind had died down momentarily, and I could marvel at the now calm, now blue, Crater Lake. The blue color is a reflection of the sky, the smoother the surface, the truer the reflection.  It seemed that the smoke in the air had mostly cleared, making today’s view of the lake a beautiful sight.

The sky is polarized. Humans can’t see this directly but wearing a pair of polarized sunglasses reveals it. Tilting your head while looking at the sky will show it to lighten and darken with your tilt angle. I wondered what happens to the polarization after being reflected by water. I took various pictures of the lake through a polarizing filter I had brought. My results were inconclusive, but attractive, nevertheless. A reflecting surface adds a polarizing effect of its own (polarizing sunglasses are designed to cancel it), and the combination becomes more complicated than I was willing or had time to figure out.

I also enjoyed watching the sightseeing boat that motored around in the lake. Its wake propagated uniformly and unhindered across the glass surface, until eventually encountering the shore, which then reflected back out into the lake crisscrossing itself. Just like the physics wave lab tanks, but on a grand outdoor scale!

The famous still blue waters of Crater Lake host tour boats and sustain wave fronts from them that propagate across the entire lake (a view looking down from the rim).
A view from Phantom Lookout, testing the effects of a polarizer filter (right).  Polarizers are often used to accent the blue of the sky, but in this case, Crater Lake is not really in need of further enhancement.

Nightscape Odyssey
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6 Crater Lake

6.1  Forest Fire Crater Haze

Though it doesn’t seem so from the maps, Crater Lake is not an easily accessible park. It is tucked away in a zone straddling forest and desert, and only a few roads provide access.

I stopped in the town of Roseburg, the exit point from the I5 freeway to start the blue-highways route to Crater Lake. This was the last town of a size that might have an adequate camera store. I needed a cable release to replace one that had failed. A cable release, the mechanism that provides long duration exposures by keeping the shutter open, is essential for astrophotography. It works by using a flexible wire inside a sleeve. One end has a pushbutton plunger that is used to push the sliding wire down the sleeve, acting as a “finger extender” to trip the shutter. This allows you to take a picture without actually touching the camera with your shaky hands. When the camera is set to “B” (a reference to the now obsolete flash bulb-mode), the shutter remains open for as long as the cable is pushed in. For really long exposures, there is a convenient feature on the cable release that lets you lock it in place, allowing you to walk away from the whole setup while the shutter remains open. Come back in an hour and unlock it to finish the exposure.

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