omarsultan wrote in post #13795141
I was intrigued by the article on the coming annular eclipse in the Feb '12 edition of Sky and Telescope since it will be in my neighborhood. So, two newbie questions:
Do I simply need a solar filter for my telescope--is there any particular kind of solar filter?
Any hints on exposure?
You want to make a filter from Baader AstroSolar Film to fit over the front of your 70-200 with the 1.4 attached. There's a guide here. Make sure the filter cannot be knocked from the lens by accident - use a lot of tape. Do not be tempted to use mylar, welding glass or ND filters. There's a good chance that they'll block the visible light but pass the IR. If you're lucky it'll just fry your sensor, if you're unlucky it'll fry your retina.
You really want a longer lens than the 70-200, even with a 1.4x. To fill the frame you'd need something like 1500mm on an APS-C, so 280mm will make for a small image.
For exposure - try it on the sun before the eclipse. About 1/400s; f8; ISO200 will be a good starting point.