btw - do i need some degree of darkness to use a fluorescent bulb as a strobe? coz i can`t see _any_ pattern on cd (used in place of rsg disk, has 1cm wide stripe painted with black marker, then i painted 1/4 of the disk surface with the same result - no results) at day light : \
Dmitry, The fluorescent bulb must be the old ballast type not a high frequency switch type power supply type. Usually i can see the pattern with some daylight in the room. Darkness may help. The pattern will be very blurry and diffused so it can take some practice to be able to see the pattern. Some folks took many days of practice to be able to see the pattern. I like to make a line all the way across the disc diameter rather than painting just 1/4 of the disc. Not sure how the 1/4 disk-paint idea would show up because I never tried it.John