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Astronomik H-Beta |
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The Astronomik H-ß filter is designed for visual observation of gas nebulas with larger scopes. Due to the extreme small band pass of the H-ß line, the filter will produce a maximum increase of contrast even under best observing conditions. At faint H-II nebulas the Astronomik like the horsehead nebula the H-ß filter often makes the gain, that decides if the object can be seen or not. With the Astronomik H-ß you will be able to see the horsehead nebula with scopes of 10"...12" aperture under good skies. The best focal ratio for the use of this filter is 1:4.5 to 1:6. The field of application is from 1:3,75 up to 1:15. Loss of transmission and colour displacements, that appear at other filters, emerge with the Astronomik filters only at extreme light intensive focal ratio of 1:3 and bigger. So you can see widespread objects in the whole field of view and not only in the middle. The H-ß filter is to be used from a aperture of more than 8" (20cm) on. At smaller instruments there is not enough light available for a sensible use. Due to the well- known high optical quality of the glass substrate you will see with the Astronomik H-ß filters still the needle-sharp stars, that you know to from your instruments.
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The red lines are the most important lines from artificial light pollution. The green lines are the most prominent emission lines for nebulas. The grey curve is the human eye´s night-sensitivity. The blue line is the transmission curve of the filter. |
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