Posted by A R Pratt at 11:31 on 2013 Feb 12
Hi Marlyn,Yes, I agree that the presenters stressed the dangers of solar observing. Unfortunately, the programme didn’t discuss the pros and cons of solar projection, which was the only method available to me in the 1960s and ’70s, when my mentor was Harold Hill. Since then I have made – and purchased – a number of solar filters.I was concerned that a member of the Flamsteed Society used a home-made mylar filter that was loosely seated inside the rim of the dew shield of his refractor. We didn’t see the filter secured in place.A few years ago a member of a local astronomical society mentioned that he’d made a solar filter for his 20cm SCT, but it gave very dim and blurred images of the Sun. I inspected his mylar filter, which was well made and was tightly secured over the front of his ‘scope. Then I noticed his design flaw – the mylar aperture was in the centre of his cardboard disc, sitting precisely in front of the secondary mirror obstruction! No wonder he couldn’t see the Sun through it. :-)Clear skies, Alex.