Estimated Arrival: Between Oct 22 and Oct 28. *ETA to USA Only
Shipping & Returns: Satisfaction guaranteed 30 day return policy.
The IDAS Hydrogen-Alpha family of filters allows astrophotographers to select an Hα filter optimally tailored to their equipment.
UHS(Ultra High Speed) version, which is ideal for RASAs and HyperStars
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 astrophotographs. In additon 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.
- Ha 6.5 +/- 0.1nm (measured value)
- 98% transmission rate (measured value)
- Class UHS
- 3.0mm thickness
- Ideal for RASAs and HyperStars
- Fully blocks up to 1200nm as illustrated in the plot
- Made in Japan
Detailed Filter Plots:The plots below show the different filter performance with various astrograph designs - refractors vs. telescopes with central obstructions.
Reflection Test Sample:This test (200 second exposure) shows clean images of bright stars in the field, indicating good anti-reflection (AR) design.
Examples from Bortle 8 skies (5-minute exposures):
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