Shouldn't your cave map note the normal threshold boundary of total darkness?
Here is an e-mail I received from a company that sells a gadget that could measure light intensity in a cave passage and possibly determine the boundary line of total darkness in a cave: _____________________________________________________________ Our system will provide you with accurate measurements of the light intensity, or lack of it. The range is 0.001 ft candles to 140 ft candles. The device is a handheld portable meter with a sensor connected with a cable. The meter has a backlit screen, so when taking readings you will have to make sure this is turned off, otherwise it will have an impact on your readings. This sensor is only measuring light, which is the visible part of the spectrum. It will not record any UV or IR radiation. If this is what you are looking for, the meter and sensor will cost $1,385.00, FOB Glenside, PA. Best regards, Terry Harding Director of Sales & Marketing North America Solar Light Company, Inc. 100 East Glenside Avenue Glenside, PA 19038 (215) 517-8700 (215) 517-8747 fax www.solarlight.com ___________________________________________________ David Locklear Fort Bend County, Texas --------------------------------------------------------------------- Visit our website: http://texascavers.com To unsubscribe, e-mail: texascavers-unsubscr...@texascavers.com For additional commands, e-mail: texascavers-h...@texascavers.com
