the sun's still shining here in Paris and despite partial lockdown I can still watch the sun with my spectroscope through my little window under the rooftop
Here are some recent pics but this time I wanted to experience the Secchi experience with a 600 l/mm diffraction grating instead of the 1200l/mm grating that I usually use..
Secchi described in his book that he was given a grating by rutherford and that the dispersion gave him the dispersion of his 7 prisms spectrocope : the grating had about 600 l/mm and the collimator focal lenght is 130mm (mine is 180mm).
The results are interesting : the image is more detailed even though I have to open the slit less wider. An interesting fact compared to the use of the 1200 l/mm is the fact that the chromosphere "ribbon" is much less thinner and that the spicules are more easily seen.