I've just taken delivery of a lovely new ZWO ASI 24MC Pro camera. ?.  It will be used with my 80ED with focal reducer with an M48 rear thread.  The spacing required between the camera sensor and the back of the focal reducer is 55mm.  Unfortunately my skies at home a pretty light polluted so I'll need a light pollution filter when using this camera at home.  Our local council have nearly finished swapping out all of the old sodium streetlights for LEDs.  The best light pollution filter for