My Astronomical Filters
I used my new Alpy600 spectrograph from Shelyak Instruments to analize my astronomical filters.
I exposed an image with and without the respective filter, using an Halogen lamp and a light diffusor. By dividing the first by the second and normalizing the result, I obtained the filter response.
The LRGB filters from Astronomik are very well balanced.
The narrowband filters of 13 nm bandwidth show a broader bandwidth but include well the two OIII lines, the H-alpha line and the two SII lines. The 6 nm H-alpha filter, is slightly decentered from the H-alpha kine:
These filters do not have frabricant, and the only one with some quality is the IR-Pass. The nebular misses H-alpha completely.