Specifications

AUTOSTAR CCD PHOTOMETRY 93
The joints may be attached together using a hot glue gun, or tape
(fabric duct tape or packing tape). RTV or silicon adhesive
(bathtub caulk) could be used, but the advantage of hot glue is that
it dries rapidly, thus the panels don't need to be supported in
position for very long. Some attention should be paid to access to
the interior, for adjustment of the lights or cleaning. Perhaps a side
panel or the top should be arranged for easy removal.
A layout should be planned for sheet cutting. A few web pages
discussed round or tubular designs; some were constructed in sheet
metal; and one web page described a box made of thin plywood
(door skin material comes to mind); but that would need to be
either lined in white material or painted to be reflective inside, and
would necessarily be heavier.
Attachment – To attach the lightweight box to the end of the
telescope, a soft plastic foam ring or collar is usually shaped or cut,
to fit around the end of the tube, and placed inside the end of the
box. But construction grade Styrofoam "bead board" is to be
avoided, as it tends to shed particles which will stick by static
electricity to the diffuser panel inside the box. Flexible
polyethylene foam blocks or sheets used in packing material may
be readily salvaged and put to use. Sometimes large thick sheets
can be obtained, from which a complete ring or collar can be cut.
Diffuser Panels – Most light box designs employ one or two
diffuser panels mounted across a ring or bulkhead with an opening
of at least the full size of the telescope aperture, cut from the same
foamcore material as the walls of the box. Frosted translucent
drafting mylar sheet or vellum is usually recommended, although
this material is rapidly becoming difficult to obtain, as draftings
are now created and stored electronically. Thin milk–white opaque
plastic sheet may be obtained from sign shops or plastics dealers.
But the thickness must be selected so as to pass adequate light.