|
The Ultra Block filter as I understand it is a narrowband filter designed to reduce the effects of light pollution. It allows ionised oxygen (presumably OIII primarily) and Hydrogen beta light through and blocks everything else(according to the Orion website). Our eyes detect OIII as green or greenish blue and Hydrogen beta as red, but our eyes are much less sensitive to red, so yes it will cause the nebula to look a bit green.
Looking on the Orion website there is not a lot of info but it does suggest this is for areas that experience significant light pollution, so Brisbane is probably good spot to try it!
Did it come with a transmission graph showing exactly what the transmission of light is like?
Malcolm
|