P810/xxx/yyy - Long-Pass Illumination Filters
Shown cut to size for fitting into microscope filter holder.
Shown cut to size for fitting into microscope filter holder.
Fitted in the path of a standard microscope light source, these filters serve to transmit infra-red whilst blocking light of shorter wavelength. As biological fluorescence tends to be in the visible region of the spectrum, and most photomultipliers are insensitive to infra-red, the preparation can be viewed using a CCD camera (CCD cameras are sensitive to infra-red) without affecting fluorescence measurements.
The stock wavelengths are 715nm and 780nm (others may be supplied to order), 715nm being recommended for most applications, unless an S20 PMT is in use, in which case 780nm should be used (e.g. for snarf-1). The xxx in the part number indicates the cut-off wavelength.
