H-Alpha and prominences

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RE: H-Alpha and prominences

Postby brianb » Tue Jun 08, 2010 10:20 am

[quote]How does using a filter make more light visible (Prominences are not visible in normal white light)? Are they blocked out by the intensity of the disk? [/quote]
It doesn't. What the filter does is transmit (most of) the light emitted by the prominences, whilst absorbing or reflecting (almost all of) the light in the sky background - which is very bright indeed close to the sun.

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RE: H-Alpha and prominences

Postby brianb » Tue Jun 08, 2010 4:43 pm

Yes. Remove the scattered light - a total solar eclipse works well enough - and the prominences become visible. Narrowband Ha filtering is the best way of removing scattered light outside a solar eclipse.

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RE: H-Alpha and prominences

Postby philip pugh » Thu Jun 10, 2010 7:16 pm


[quote]ORIGINAL: brianb

Yes. Remove the scattered light - a total solar eclipse works well enough - and the prominences become visible. Narrowband Ha filtering is the best way of removing scattered light outside a solar eclipse.


[/quote]

... and a Coronado PST or Lunt LS35 is a lot cheaper than travelling to a total solar eclipse outside the UK. George, you'll probably be around in 2057 to see the next one in the UK but I and many others here will be long gone.
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RE: H-Alpha and prominences

Postby philip pugh » Mon Jun 14, 2010 10:13 am


[quote]ORIGINAL: george7378

I hope we all see many more eclipses in the future :)

Also, I was wondering - has enyone ever seen (or heard of) prominences on the edge of the Sun viewed at sunset? Is it theoretically possible if you have a flat and round horizon?
[/quote]

If you mean in "white light" without H alpha filters, then no because a lot of sunlight (of all wavelengthds) gets scattered by the atmosphere. In a PST from England, it's possible but would need a very clear day. I've seen pictures taken at sunrise and sunset with a 90mm solar hydrogen alpha telescope from Texas.
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