光害カットフィルターと ルミコンＨ−アルファフィルターの併用 Sigma Telephoto Zoom Lens of 150-500mm FL at 500mm, Canon EOS Rebel T3, self modded, ISO3200, Exposure time 2 minutes, 27 lighs, and 20 darks and flats each, Lumicon H-Alpha filter with IDAS IPS P2 filter, combined together, being used as a semi-narrow band filter. The transmission wave length is between 635 nm and 680nm , roughly 45nm band width at the half peak. Note the H-Alpha peak is 656 nm. Refer to http://www.sciencecenter.net/hutech/idas/filtplt.htm for LPS P2 and http://www.astrosurf.com/buil/filters/curves.htm for Lumicon H-Alpha pass filter (this filter is a low pass filter, not a band pass filter). The star images were superimposed with the shots (45 seconds exposure frames) taken without the Lumicon filter