A Nebula Booster Filter - 52 mm:
This new nebula filter is permeable to the spectral lines H-beta, Oiii, H-alpha, and Sii - and with very high transmission. This makes it ideal for the photography of large fog areas, in which it lets pass the typical colors of these objects and blocks the disturbing sky illumination.
In particular, the filter quickly cuts off the near infrared, all the way up to 1100 nanometers. This is important because cameras are sensitive to this area, but the telescope optics are optimized for the visible spectral range and faulty in the infrared range. The Nebula Booster is particularly suitable for fast lens optics , as they are preferred for the astrophotography of large fields. The filter glasses are 2.5 millimeters thick. It can therefore be exchanged with other 2.5 mm thick IDAS filters without changing the focus position.
Image Note: This is for the 52 mm filter only, the 48 mm filter is shown for size comparison and availability.