The IDAS Hydrogen-Alpha family of filters allows astrophotographers to select an Hα filter optimally tailored to their equipment.

Features include:

• 6.8 nm bandpass (measured value 6.5 +/- 0.1 nm)
• 98% transmission (measured value)
• IR blocking out to 1200 nm
• 2.5mm and 3.0mm filter thickness options
• Configurations:
  • 50.8mm for filter wheels (QHY/ZWO/Atik)
  • 48mm and 52mm mounted
• Each filter is individually measured and inspected for quality
• 3 classes* available: STD, HS, UHS
• Made in Japan

The IDAS Ha-6.8 family includes 3 options - STD (Standard), HS (High Speed) and UHS (Ultra High Speed) with bandpasses adjusted to accommodate the f-ratio of different speed astrographs. In addition each class comes in two different glass thicknesses - 2.5 mm & 3.0 mm.

• STD - recommended for most regular scopes
• HS - ideal for the optics between F2.0 and F3.5 such as Takahashi Epsilon Series, RASA11, and standard camera lenses
• UHS - highly optimized for the optics for F2.2 or faster such as RASA8 and HyperStar Series

Prices are the same across the filter family regardless of the option selected. Filters are designed to fit in 50.8mm QHY, ZWO and ATIK filter carousels.