CFHT Interference Filter Database Description and Recent Additions

HTML version created by Greg Barrick

Maintained by Greg Barrick

Last updated: 31 December 1998

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The stock of CFHT filters available for CFHT users is now quite large. The list of filters and the transmission curves for the filters are maintained on the WWW only. This list is updated periodically as new filters are added to the list. The filter transmission curves will be updated as time for scanning of filters permits. The database currently only contains interference filters.

The filter transmission curves are, at this point in time, done with the filter at room temperature. This will shift the central wavelength and alter the bandwidth of the filter. This effect should be slight for visible filters that are operated at about 0 Celcius. The effect is much greater for IR filters. We would like to add the ability to scan filters cold to our spectrophotometer, and will when time and budget permits.

The spectrophotometer is only capable of scanning to 3.2 micron, so filters with wavelengths above this hve no filter curves in the database.

Further information on the database and its use can be found in:

The filters are located in the new Spectrograph Lab on the 2nd floor. A checkout sheet is now available in the cabinet with the filters. It would be of great assistance in keeping track of the interference filters if everyone would fill out the information requested on the sheet when removing filters from the cabinet.

The filters have been reorganized according to CFH filter number and all filters listed with the exception of the photographic camera filters have this number engraved on them.

It would be greatly appreciated if all new filter orders were placed through me so that I may keep the filter list and the filter cabinet as up to date and as organized as possible. Attached is a standard filter order form for CFHT use only. When ordering new filters, please fill out this form and return it to me. A quote will be requested, usually from Barr Associates unless another company is specified, based on the information provided on the order form.

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