OK, had a go with Rob's design this morning, modified to use a needle rather than aiming at a wall or other white surface. Didn't have a ready-made tube, and not willing to wait for the Glad Wrap to be used up I rolled up thin card with a sheet of black paper. Added a black paper 'shield' to cut down extraneous light entering the tube.
With the shield on, you simply tilt the "spectroscope" (ha!!) down at about 45-deg to the incident sun rays, look through the peephole and rotate the tube slightly until the Sun reflects 'squarely' off the needle.
Awesome, very clear spectrum with so many fine strong absorption lines showing!! The needle used was finer & smoother than the one I used previously.
Photography is problematic & I won't even bother trying - this is just a simple, cheap way of introducing yourself (& students?) to the solar spectrum (and other bright light sources - good job on various lights around the house last night).
Great job, thanks Robz!
Cheers -