William Anthony Photography

The above image shows a portion of the large North American Nebula (NGC7000) in filtered H-alpha light. The prominent Gulf of Mexico can be seen as a dark area to the right and center. This image was taken with a narrow band hydrogen alpha filter that greatly increases the contrast in emission nebula. Imaging with a narrow band filter has many advantages. The H-alpha narrow band filter is very effective at blocking light pollution and moon light. But the decrease in light hitting the sensor requires longer exposure times and higher ISO settings. Calibrating the mount, focusing the scope, and composing the object are much more difficult when using the narrow band filter. The image is 10.6 hours worth of data shot over 3 nights.