Notes from special presentations, valuable tips, and "how to" guidelines can be found below and at the following links to PDF files.

Suggested Process

1. You must have a very stable (heavy/solid) tripod, a remote actuation for the camera, and the ability to maintain the settings while sighting the picture between the two exposures.

2. Take the first exposure at the peak/best time for pre-dark sky exposure. Compose it correctly, doing everything as you normally would, but set the exposure such that the image is one stop under-exposed.

3. Thirty minutes later, after it's fairly dark and building lights are on, take another exposure exactly the same as the first but at normal/proper exposure for the new light level. (Winter time works well because it gets dark earlier and lights come on sooner.)

Photo by Randy Zwiers