Hello,
Today in Paris i was blessed with a nice sunny weather...with a very white milky sky....
but still i've been able to get the best image ever with my technique!!!
I modified my spectro-coronagraph : I took away the Lyot stop and put an Iris diaphragm against the collimator. Indeed after several trials during numerous session I realised I could fairly get the same results and the benefit of having a much lighter and shorter instrument.
So I made several trials with all my diffraction gratings from 2400 to 600 lines/mm... and guess what :
my hypothesis is verified : the less dispersion and the best definition it gets. Its because a point from the object ( a prominence ) becomes a ligne in a spectroscope. The width of the "line" depends on the dispersion. The h alpha line is about 1A "large". So the more dispersive is the spectroscope and the wider the "line" tends to be and then my image isnt made of points anymore when I use high dispersion.
Judge by yourself :
now , i'm tempted into buying a 300 lines/mm
Chris
prom of the day : spectro with low dispersion
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prom of the day : spectro with low dispersion
spectro-coronographe ,Bresser 127/1200 ; Bresser 102/1350 , ASI 178MM
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Re: prom of the day : spectro with low dispersion
There are some beautiful detail in these prominences
Alexandra
Alexandra