> On 10 Mar 2017, at 22:02, Mark Roberts <postmas...@robertstech.com> wrote: > > Bob W-PDML wrote: > >> There's a purpose-built camera obscura here in Greenwich, by the Royal >> Observatory. It's fascinating to watch. The light enters through a cupola >> and is reflected onto a round viewing table. I believe it may be possible to >> rotate the cupola to change the view. >> >> I can't imagine it being too difficult to rig something up, provided you can >> get the blackout material. > > Yes, I've been to see the one in Greenwich. And a couple of others, > too. What I really need to know is about techniques/materials for > blacking out the room and, most importantly, what size aperture (hole) > I should use. >
I'd have thought some mixture of blackout curtains and cardboard boxes over the windows would do it, with some judicious stuffing of lights leaks around the door. Start with a small hole in the cardboard with a pencil or biro, and make it larger as needed. -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions.
