Spectrograph Project Page 
More filter scans and plant material
Uploaded 3/30/14

 

            
Here are some more
            scans with the spectrograph with a 300 lpmm grating, and the
            DMK31 camera. Zoom was set for about half way to 30mm on the
            imaging lens so that I could get in the entire visible spectrum
            at once. To take these, A UV/IR blocker filter was installed
            and the resulting spectrum centered on the display. Then it was
            removed, and a Neon lamp was imaged for calibration. This was
            followed by a shot of the Halogen lamp used to back light the
            filters and of a white card illuminated by the Halogen lamp -
            these will be divided into the filter spectrums for a true pass
            band result. 

            
The white card
            was scanned for a reference so I could then put a huge handfull
            of crab grass in the light to get its reflectance spectrum seen
            below. Finally, the spectrum was shifted such that the visual
            spectrum was just barely on the left edge and the full span of
            IR to 1 micron was the full field. The neons IR lines aided in
            calibration of this set. 

            
Click on small
            graphs for the full size image!

 

            


            
Halogen lamp used in scans

            

Meade IR blocker filter to define
boundries of visible range
(removed for all scans)

            

Green gel filter in 1.25 holder
for visual observing

 

            

Hoya R72 Infra red filter
visible range only

            

Hoya R72 Infra red filter
IR range only

            

Orange gel filter in 1.25 holder
used for visual observing

 

            

Wratten 47 (deep blue)

            

UV LED flashlight

            

Green vegitation - crab grass
Visual Range.  Note the big red
blackout, but then in IR it comes on
strong.  The Hoya R72 will work fine here!

 

            

Green vegitation - crab grass
Visual Range. Expanded range with IR cut.

            

Green Vegitation again
IR Range only. seems best at around
800 nm.
 




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