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filters etc
Thanks everyone
Robert, I only use a red filter to remove blue light which is scattered more and so degrades seeing. An infrared pass filter would also provide clear views, however I don't have one yet (its on order). An IR block would be a poor filter since this would pass only visible light which is more affected by scattering that IR light. The resulting image would not be as good as with a red or IR-pass filter.
If the seeing is superb, a blue filter is better. This is because resolution is inversely proportional to wavelength. The shorter the wavelength, the finer the detail that can be seen. However this only works when the seeing is really really good since blue light is highly scattered. Its a close tradeoff.
Bottom line is, if you have an IR block filter, don't use it with a red filter for the Moon (for b/w imaging). An IR-pass only is a good choice too, but then the red is unnecessary.
As usual, my emails are clear as mud.
zac
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