The external filter prevents the telescope inside from heating up.
High-quality interference type of filter
60nm bandpass (central wavelength : 656.28nm)
Over 95% transmission at Ha emission line
OD 4 between 200nm and 1100nm
Glass thickness : 12.0mm
The filter assembly is comprised with a filter holder unit and a dew-shield adapter.
Available at 190mm, 140mm and 120mm effective apertures at this moment.
The set comes with a customized dew-shield adapter. So perfectly fits your scope.
The dew-shield adapters will be sold separately as an optional items later. So each user can switch ERF to another telescope by changing only the dew-shield adapter.
A couple of weeks lead time due to the custom-made process.
Affordable price in its size and quality
We have the mechanical data on following telescopes as of August 23 2022.
