Filters used in acquiring astronomy image data.

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DavidLeodis
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Filters used in acquiring astronomy image data.

Post by DavidLeodis » Sat Mar 15, 2014 9:05 pm

I would like to know if Hydrogen-alpha, OIII and SII filters can be used to obtain image data even in daylight :?: I assume that Red, Green and Blue filters have to be used in darkness.

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Chris Peterson
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Re: Filters used in acquiring astronomy image data.

Post by Chris Peterson » Sat Mar 15, 2014 10:53 pm

DavidLeodis wrote:I would like to know if Hydrogen-alpha, OIII and SII filters can be used to obtain image data even in daylight :?: I assume that Red, Green and Blue filters have to be used in darkness.
No. The objects that emit at these wavelengths are very dim, which is why narrowband imaging typically requires such long exposures. You can image pretty well under moonlight or light pollution, but the daytime sky is just too bright, even in a band just a nanometer wide.
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DavidLeodis
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Re: Filters used in acquiring astronomy image data.

Post by DavidLeodis » Sat Mar 15, 2014 11:34 pm

Chris Peterson wrote:
DavidLeodis wrote:I would like to know if Hydrogen-alpha, OIII and SII filters can be used to obtain image data even in daylight :?: I assume that Red, Green and Blue filters have to be used in darkness.
No. The objects that emit at these wavelengths are very dim, which is why narrowband imaging typically requires such long exposures. You can image pretty well under moonlight or light pollution, but the daytime sky is just too bright, even in a band just a nanometer wide.
Thanks Chris for that very helpful reply, which is appreciated. I had wondered, if like radio astronomy, that the filters may be usable in daylight as well as darkness. :)