|
Solar spectra with SA grating
Al,
The needle idea will work if you get the orientation and distance right.
An alternative I used is the Surpus Shed adjustable slit mounted ( wooden spacers/ gaffa tape) in the end of a length of PVC tube. I used a 50mm tube with a PVC 32-50mm reducer at the slit end, about 2 metre long.
This focussed with the Canon 350D standard lenses and the Baader grating.
Watch out for the rotation of the lens during focussing, I found the canon lens "rotated" while reaching automatic focus, and the grating had to be re-adjusted to align with the slit. To make it easier for me I wrapped a small elastic band around the thread of the grating to give me some rotation with resistance. (This set up can also be used with a flouro reference lamp for indoor trials)
I checked some of my Canon 350D calibration shots, and yes the responce drops dramatically below 380A ( makes observing the CaK lines difficult); I need to test and calibrate the ATiK16ic...... always something to do!!
Weather permitting I'll take some shots of Altair, Deneb and Vega over the next few nights for "practise" with the Baader mounted on the Genesis with various cameras......
My Littrow is temporarily out of commission while I re-set the neon calibration and add a back light to the slit.
|