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Tried a hydrogen alpha filter on my 8 inch dob, got a red disk with no details
Bought an off-brand Ha filter off ebay for 80 bucks and slapped it on my telescope last saturday, thinking Id see solar prominences like the pros post here. Instead I got a featureless red circle that looked like a bad screensaver, totally wasted a clear afternoon fiddling with the focuser. Was my setup just way too slow for that filter, or did I get a dud that only works on fancy refractors?
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sullivan.spencer17d ago
Check the label on that filter again, because a plain Ha filter for deep sky imaging is not the same thing as a solar Ha filter. Deep sky Ha filters pass a wide chunk of red light around 656nm so you can shoot nebulas at night, and they block almost everything else. Solar Ha scopes and filters pass a crazy narrow slice of that same wavelength, like under 1 angstrom, and that tiny slice is what shows you the chromosphere and prominences. Your filter let too much light through at once, so the whole sun just turned into a red blob with no contrast, no matter how sharp your focus was. A dob is also the wrong tool for this since you can't track the sun and it'll drift out of view fast, but the filter itself is the main problem here.
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