Here's a small astrophotography lightbox I threw together for 4 1/4" to 6" class telescopes using a "moon" tap light, an 8"x8" UPS shipping box, two pieces of milk plastic, one 20"x32" artist whiteboard and white duct tape.  The box is 8 inches on a side.   http://members.csolutions.net/fisherka/astronote/atm/smlightbox.jpg   It was inspired by Russell Croman's 2005 design.   http://www.rc-astro.com/equipment/light_box/   I have not tested the field for white light flatness with a camera, but visually it looks fine with an eyepiece at 40x.   Clear Skies - Kurt