Hi Brent: Keep on digging, you perform a valuable service. Amateur astronomers display a variety of practices, and we sometimes tend to do things "because it's always been done like that". Always better to know why, than "just because"...sometimes a little investigation can seperate the myths from the facts. You've been doing this longer than I (34 yrs. this yr.) and you still manage to teach me a thing or two once in a while! C. --- Brent Watson <brentjwatson@yahoo.com> wrote:
Chuck,
I agre - err on the safe side. I just like to dig a bit deeper.
Brent
--- Chuck Hards <chuckhards@yahoo.com> wrote:
Brent:
Pinholes do not come in a "standard size"; indeed for the hole size you mention, you are quite correct in that the throughput is miniscule.
But if the hole is just a bit larger, say .050" (4x the unfiltered area of a .010" hole), then I think it's time to get concerned, especially when the eye will be at the eyepiece for an extended period.
To err on the side of caution, if you don't have a measuring loupe, just opaque them all and don't worry about it.
Safety aside, pinholes can have a harmful effect on contrast.
Chuck
--- Brent Watson <brentjwatson@yahoo.com> wrote:
Chuck,
I know this is the standard safety warning, but it has never made any sense to me. If the pinhole is 1/100 inch (.010") in diameter, and it is in a filter that is 70 mm in diameter for a bino, then the pinhole represents only .00015% of the area. This is a miniscule increase in the energy transmitted. If there were 100 pinholes, the area would still be only .015% of the total.
I have actually heard some folks say that the pinholes did NOT matter because they were so small.
Your opinion?
Brent
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