Coronado SolarMax II Etalon 40mm with block filter BF10
Item description of the manufacturer:
This set consists of a H-alpha etalon with half width less than 0.7 angstroms and a block filter integrated in a zenith prism.
With this combination you can convert your refractor (telescope) into a telescope, with which the safe observation of the sun in H-alpha-light is possible. In the H-alpha line of 656 nanometers wavelength, you see the chromosphere of the sun, that is, the atmosphere layer above the solar photosphere. Observe protuberances, filaments and other temporally variable phenomena. There is always something going on in the H-alpha light on the sun!
Note: Safe use is only possible in the combination of etalon and block filter. No single part is sufficient as a filter!
For the choice of these solar filters two statements are essential: The first number in the product name indicates the diameter of the etalon, the second the diameter of the block filter.
Blocking Filter BF: The deflection optics with the eyepiece mount houses the block filter. This filter reduces the brightness of the sun image and is therefore a very important part of the overall system solar telescope, which must not be removed!
The number after the abbreviation BF in the product name indicates the diameter of the block filter in millimeters. For example, BF10 means that the block filter is 10 millimeters in diameter. For purely visual observation, a small block filter is sufficient, for photography a larger one should be chosen.
The size of the block filter should be chosen so that the whole solar disk can be seen. The larger the focal length of the telescope, the larger the sun image and thus a larger block filter is required. In the technical data you can see the recommended focal length for this set.
RichView ™ & T-Max tuning: The H-alpha filter is a so-called etalon. In the etalon, most of the radiation in the visible spectral range is extinguished by destructive interference of the incident light. Only the desired wavelength around 656 nanometers comes through.
For this to succeed, the width of the etalon must be set exactly and readjusted during observation. Point the telescope at the sun and focus with the focus on the edge of the sun. Turn the large turntable of the RichView ™ system until the structures on the sun are visible in maximum contrast. Then you can easily tilt the inclination of the Etalon over the small Max-Tuning-wheel, in order to reach the maximum image brightness.
Technical specifications: power Version lens filter Connection (eyepiece side) 1.25 " Connection (telescope side) 1.25 " Insight 90 ° Suitable for telescope refractors Suitable for focal length (mm) <1000 General Series SolarMax II Type solar filter Type line filter