Astronomy

What is a Spectrohelioscope



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The spectrohelioscope was invented in 1924 by George Ellery Hale, it is used to detect sudden outbursts of activity on the surface of the sun. The name Spectrohelioscope can be directly derived from three latin words; Spectro, which refers to the electromagnetic spectrum, Helio, which means sun and Scope which we use in the same way in english today. The spectrohelioscope was designed specifically to observe the sun at a particular wavelegnth.

A spectrohelioscope is a fairly complex machine which uses a spectroscope to observe the surface of the sun. A spectroscope was invented by Joseph Von Fraunhofer is commonly used in astronomy, the simplest versions used prisms which marked various wavelegnths of light, but the new models are far more complex. A monochromator is the modern counter part which uses a diffraction grating to split the light into its various wavelegnths, a moveable slit to focus the light onto an autodetecter, this is all controlled by computer which also logs the results. The techniques used can be based around Reflection optics, refraction optics or fiber optics.

Each material gives of a different signature of wavelegths charactaristic to the elements from which it is made, for example, we know something contains sodium as it gives off a very charictarist light spectra of two yellow bands at 588 and 589 nano metres. By logging the spectra of every element we can probe the sun finding out the chemical makeup of its surface, and when a change occurs it undergoes a change which is visible to the Spectrohelioscope, which is effectively a spectrometer set up for the intense light and wavelegnths of the sun.

The slit idea causes a problem because it can only view a slice of the surface, so moving the slit gradually across the surface is the only way to get a complete image of the sun.

An excellent project was completed by Leonard Higgins with the support, and guidance of Fredrick Veio, when the pair built there own spectrohelioscope, which has won numerous awards and has been on display at the RTMC (Riverside Telescope Maker's Conference) at Big Bear Lake, Camp Oaks in California, USA.If you want to see how its all possible have a look at there website:

http://www.spectrohelioscope.org/Higgins/SHS02.htm

It has a very good photographic guide of the building and operations of the spectrohelioscope. They used reflection and sets of lenses to focus the light of the sun onto a sensor which records the data.

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