two 6nm Ha filters together

[Baron von Richthofen]

Hi All
What would be the affect of putting two 6nm Ha filters together, would it reduce the band width and by how much
Vars

[DavidU]

I don't think anything would be gained by this. A sharp attenuation at 6nm would have that small portion attenuated again by the same ratio however all other wavelengths would also be attenuated.

[allan gould]

Whatever the band pass percentage of light is with one filter at Ha wavelength ie 50%, then with two filters it will be 50% of 50% ie 25%. No advantage what so ever in stacking them

[netwolf]

If the filters are exactly the same, then as advised above the bandpass regions will just over lap and make not diffrence to the bandwidth being passed.

I also agrre with Alan the forward transmission coefficent will be doubled, and hence the signal being passed throught would be atenuated further.

So you loose signal strength and gain nothing.

Even if one had a narower BW response/profile than the other, you just lose signal strenght and achive the bandpass of the narrower filter. Which you can do just by using the filter with the narower response, and retain the orignal signal stregth.