The Marshall Point Lighthouse is located near Port Clyde in the state of Maine. Although the grounds are usually closed at night, I was able to photograph the light while attending a workshop led by Lance Keimig who runs the Night Skye Workshops. The workshop was a part of the highly respected Maine Media Workshops and College, based out of Camden, Maine.
I was recently asked about the techniques used to create this image, so I thought I would post the answer here. This was created using a blend of two exposures. The first was a very long exposure of 8 minutes/f8/ISO 800. This exposure yielded the clean, noise-free overall image that also produced the star trails of a length I find pleasing to the eye.
While an exposure of 8 minutes produced a nice clean image, it also grossly overexposed the actual light at the fresnal itself. To correct this deficiency, I took a series of shorter exposures, this time judging the exposure of the fresnal itself. After several tries, I determined that an exposure of 30 seconds/f8/ISO 100 produced a good likeness of the fresnel portion of the light.
When it came time to construct the final image, I placed both the long, 8 minute exposure and the short, 30 second exposure into layers using Photoshop. From there it was a simple matter to blend the properly exposed fresnel into the overexposed fresnel of the long exposure.
Once the blending was accomplished, I used the power of Lumenzia (a luminosity masking plugin for Photoshop developed by Greg Benz) to do the final editing of the image until I achieved results that I felt was satisfactory.