What I want to do
resolve open questions from my last batch of slit tests.
1) figure out of the messy spectra I got pointing out a window was the result of obstacles in the path of my spectra. (see comments to Jeff's note)
2) test the distance the slit worked accurately at.
My attempt and results
Hardware was a borrowed iphone 4S.
shot down my block before sunset, this image clearly shows the three telephone poles receding in the slit's view (the three black lines, horizontal in SW) :
The fuzzyness I saw in the earlier solar spectrum was obstacles like leaves. Problem solved. This object identification is kinda cool, and helps me pick things out from the landscape:
I then wanted to see how far away I could pick up a streetlight's mercury emission lines to test distance:
Visible from 30 meters, facing sunset. Again, the pole of the streetlight is visible in the image. This image identication helped me focus on the streetlight itself:
Visible from From 50 meters, facing away from sunset:
Questions and next steps
I'm really satisfied with the new slit design! I can't wait to try to pick out flares with it.