[AstroTasmania]

Hi Daryl,

Thank you for the welcome - I hope that I can share some of my solar experiences with you.

I started making full aperture (5") aluminised glass solar filters in the 1960's (published in the BAA Journal 1966), long before they came on the market commercially. I had access to a war time optical works nearby, who were very helpful in developing my ideas, using plane optical glass flats. They had aluminising facilities and checked the flatness of the blanks I was using. I still have three which need re-aluminising & quartz coating

Commercial glass filters of the Thousand Oaks type are excellent value for the price, I have been using several for the past 20 years. Like anything else in optics, the more you pay - the better it gets.

Interferometer tests show the Baader film to be superior to glass filters, but in practical terms for visual use I prefer the orange colour of the chromium on glass filters.

Regards