- 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.
BORG : 150ED/125ED/107FL/100ED/90FL/76ED
Sky-watcher : EvoStar 150ED/120ED
- Specify us the accurately measured circumference data for the dew-shield if your scope is not listed above.