The Example: The images below represent the globular star cluster Messier 22 and are used to illustrate the benefits of stacking images to increase photographic signal to noise ratio.

The first raw image is a single exposure using the SBIG STV CCD camera on a Takahashi FSQ-106N - 4" refractor. The second raw image, is actually three stacked images using the Track and Accumulate feature of this camera.

Below these, the raw stacked image is a combination of the two raw images, and represents a total of four image stacks prior to any other image processing.

RAW Image 1
RAW Image 2

Exposure: 1 x 40 Seconds

Exposure: 3 x 30 Seconds,
SBIG STV Using Track and Accumulate

Raw Stacked Image
Finished Image - After Processing

The Finished Image shows how a moderate application of DDP using MaximDL can be used to bring out the faint stars without burning out the central "core" stars. Additionally, a light application of unsharp masking using Photoshop was used to enhance sharpness.

This simple example clearly illustrates the well known benefit of image stacking, and how this technique can greatly enhance photographic image quality by increasing signal and reducing noise.

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