The first set of frames shows a comparison of unfiltered, IDAS LPS filtered, and Lumicon Deep Sky filtered test shots. These were taken consecutively (all on the same evening) using a Televue Pronto and field flattener (f/7.2) on Kodak Elite II 100 slide film. To allow a side-by-side comparison, the frame comparison shot of the film strips was taken on a light table using a digital camera.

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The second set of comparison images shown below is a result of cropping and processing the 10 minute exposures out of the set above. Even better results can most likely be had by choosing optimal exposure times for each of the filtered images, and then combining multiple images in a stack. The set shown here were a first attempt (during a brief spell of good weather) to bracket the exposure. A good example of a properly exposed and processed image is on astrophotographer Mike Cook's web page.

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Note that both the IDAS and Lumicon filters have the beneficial effect of suppressing the blue halos resulting from the refractor's two-element objective.

The final comparison shots were taken without and with an IDAS LPS filter, but with a 50mm lens. With this wide a field of view, the shift in filter bandpass at large angles off axis becomes apparent. Clearly, focal lengths of longer than about 100mm are required to utilize the full 35mm frame with a light pollution interference filter.

Illumination of the foliage on the right side of the frame is from a sodium streetlight about 40 feet away, partially shaded by a tree.