From: "Alistair I. Paul" To: Subject: RE: IR flash and bat counts Date sent: Mon, 18 Oct 1999 23:36:24 +0100 Send reply to: infrared@a1.nl > -----Original Message----- > From: owner-infrared@a1.nl [mailto:owner-infrared@a1.nl]On Behalf Of > Frank Schiffel > Sent: 18 October 1999 19:11 > To: infrared@a1.nl > Subject: IR flash and bat counts > > > there's interest in counting bats at a cave entrance using IR at night. > > has anybody any knowledge of a VCR or other system that could be > set up at a location and do a count? I'd suggest a 35mm or larger > with a back and a timer that imprints on the film. that's a bit > expensive though. > > a 160 VHS tape would last 8 hours and should be adequate. > > obviously a fixed location. fixed field of view, known distance > to subject and all that so depth of field and all that are > standard inputs for the technical side of the data gathering. > > any suggestions? comments? > > obviously something that would be set up and left running with no > interaction. > > thanks. Hi Frank There is plenty of timelapse VCRs (12,24,48,72hrs and upto 960hrs on a 3hr E180 tape) coupled with a monochrome cctv camera which are very sensitive (IR down to >1000nm)0.005Lux @ f1.2 (I can scan a graph of spectral sensitivity if you like). These new cameras are as good as SIT cameras of a few years ago. Have a look at http://www.philipscss.com and look for the LTC 0500 mono camera I use this one and the colour LTC0600 and have found them to be two of the better cameras on the market at present. For lenses there is a great range with Fujinon and Pentax being about the best for cctv work but you can also get them from Panasonic and Computar with apertures as wide as f0.4 (Yes zero point four). For IR light I use a 12V 150W varifocal illuminator from TecSec Europe Ltd. with the options of 715nm,780nm or 850nm filters or white without the filter. http://www.freespace.virgin.net/tecsec.europe With the combination of LTC0500 camera Computar f1.6 7.5mm to 120mm 16:1 zoom lens and the 150W/715nm lamp I get a useful range of about 130-140m hope this helps Al. aipaul@enterprise.net