The effectiveness of baffling is based on the reduction of scattered light and in turn increasing image contrast. Scattered light comes in numerous forms ranging from the object you are viewing/imaging through to light pollution and other environmental factors. It is still possible to have a bright star in the FOV of a DSO that can cause issues. A classic example of this is the witchhead nebula (ic2118) and the star Rigel - they are quite close to one another. Baffling is only part of the problem. You also need to consider internal reflections. A good example of this is in Scott's post -
http://www.iceinspace.com.au/forum/s...ad.php?t=17523
Filter reflections can be a big problem, though many manufacturers use anti-reflective coating today. This assists, but it does not remedy the issue. Typically, the rule of thumb I follow when mounting filters is if they have a shiny/reflective side (which many dedicated astro CCD filters do), position it towards the telescope, not the camera. You’re likely to experience greater issues with reflection between the filter and CCD glass window chamber.