Hi Bob: Flattish horizons allow you to get objects close to setting at sundown, and again in the morning as twilight brightens. IIRC, M-30 is especially troubling in the morning. (It's been about 10 years since I've done a marathon...) Bigger is always better, whether under a dark-sky or light pollution. Especially with LPR filters. A filtered view through a 12.5" in the city would be roughly equivalent to an unfiltered view through a 4-inch under dark skies, in terms of contrast, but you'd still have the resolution advantage of the larger scope regardless of contrast levels. People shouldn't consider valley astronomy a waste of a light bucket. A 12.5" or 16" at a school star-party will definitely give better views than the 6" to 8" scopes that usually show up at such functions. CCD imaging is largely unaffected by light pollution and moonlight. Someone with a camera and laptop could produce outstanding images on the monitor, even from downtown SLC. C. --- RStmarie@aol.com wrote:
Along the line of Messier Marathon efforts: How much advantage would a mountain top site be (Like the Francis Peak radar site behind Farmington)? and How much aperture is enough for a light polluted area?
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