Observing the Sun H alpha


In addition to observing the Sun in white light, by the use of special filters it is possible to observe the Sun's chromosphere. This requires a very narrow bandwidth filter centered on the Hydrogen Alpha spectral line - 6562.8 angstroms. The two main suppliers of these systems are Daystar & Coronado. I myself use a Daystar ATM filter at 0.7 angstrom which allows views of prominences and some disk detail. The only drawback to the filter is that the optical system should be running at f30 to operate correctly. The Daystar filters are a combination of Energy Rejection Filter and a temperature controlled filter which is accurate to 0.5 of a degree. This f30 can be achieved by using an aperture reduction mask, or a combination of reduction mask and Barlow Lens.


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Above images show Daystar filter on Takahashi FS128 with central ERF, the LX200 with off axis ERF, and the business end of the Daystar filter.

The images seen through the Daystar filter are bright red, though you can also pick up some fine detail by converting the image to monochrome using a video camera or digital camera. A video camera is very good in reducing the brightness and increasing the contrast to bring out some more of the Sun's surface detail. Of course a 35mm camera can be used with varying exposures, bracketing to get the best shot.


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Two H alpha video images captured about 1 hour apart - some slight changes are visible in the prominences. LX200 and Astrovid 2000 captured with a Neotech card.



H alpha image captured using an 10" LX200 SCT and 35mm Camera at prime focus.


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Surface detail and prominences. Monochrome images.


Using conventional digital cameras such as the Nikon Coolpix pointed down a large eyepiece such as a 31mm Nagler can generate some quite pleasing images. The ones below were taken through a Takahashi FS128.



Further equipment developments on the Solar & H alpha front

Latest Hi Resolution H alpha Images - New

H alpha animation sequences - New

Observations of the Sun in White Light

Observing of the Sun

Total Solar Eclipse Observations

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