Solar Filters

Neil Morrison

 I also  have a Seymour Solar filter  used on  a C 90 and  90 mm F5.5 Refractor.  bought  from Rother Valley Optics , some  fairly long  time ago.  The Instructions  give advice on checking  for Pin holes (Hold the  filter  with the inside towards you  and outside  towards a 60-100 watt soft white light bulb.two feet away  from the bulb.  Any pin holes can  be blocked using a fine point felt marker , small drop of paint or typing correcting  fluid. AS many as 20 touch ups  per clear  aperture inch can be made  with no adverse effect on performance).   Seymour’s then  say that pin holes are  rare in their quality products.  Hope this  helps