Ok -I think I have taken this as far as I can go.
I obtained a surplus demo grating from work, it contained 100, 300 and 600l/mm gratings.
Because they had been used with students and were so old (they had l/inch) marked on them, they were in poor condition, with fingerprints etc..
I cut the 300 from the set, as I thought the 600 would be to diverse for the ST7 and I already have a 100 in the SA, and cleaned it up. This still left it covered with scratches.
I turned up an attachment to hold it to a nosepiece, as per Picture 1.
The results are shown in the following images. The spect was far removed from the zero image (about 2 frames) and background stars were a problem, but it did show some lines.
Merlin - those sites look good, I wish our dollar would gain some ground on the Pound or Euro. Isn't your economy dying like ours
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Terry - welcome back, remember you started this.
