DayStar Off-Axis ERF Energy Rejection Filter for 11" SCT - 100mm Version
This Daystar Instruments ERF Energy Rejection Filter provides a 89mm clear aperture for your 11" Schmidt-Cassegrain telescope for solar observations when used in combination with a Daystar Instruments COMBO QUARK.
Clear aperture: 89mm clear aperture (100mm is the actual size of the ERF filter itself, but due to the aluminium housing, it is reduced to a clear aperture of 89mm)
Inside diameter of the cap: 326mm
Comes with 3 nylon screws and felt.