Previous: Imaging filters
Up: Imaging filters
Next: Broad band filters - The RGO Glass Broad Band Filters (UBVRIZ)
Previous Page: Imaging filters
Next Page: Broad band filters - The RGO Glass Broad Band Filters (UBVRIZ)

Broad band filters - the Kitt Peak Interference Filters (BVRI)

These were purchased from Kitt Peak, as originally specified by J Mould. They have flat-topped profiles and are intended for use with CCD detectors (unlike earlier filter systems). Figure 1 shows details of these filters. Three sets exist; one for the INT, one for the JKT and a spare set at Herstmonceux.

The transmission curves are given here:

Johnson U Kitt Peak B Kitt Peak V Kitt Peak R Kitt Peak I

and some ascii tables with the filters scans are given here:

Johnson U Kitt Peak B Kitt Peak V Kitt Peak R Kitt Peak I

The original specifications are given below:

All filters to be 5cm x 5cm, 3mm thick, blocked to 1.1 micron, better than 75% peak transmission (except B 70%), MgF2 coated, no pinholes, optical quality glass.

R: Filter 7200Å = short-pass hard-coated on 3mm OG590, blocked to 1.1 micron, 75% or better peak transmission, MgF2 coated on glass side.

I: Filter 9000Å = Short-pass hard-coated on 3mm RG-M9, blocked 1.1 micron, 75% or better peak transmission, MgF2 coated on glass side.

V: Filter 6000Å = Short-pass hard-coated on 3mm GG 495 blocked to 1.1 micron, 75% or better peak transmission, MgF2 coated on glass side. (Sent back did not come up to specification, 1/6/81)

B: Filter 4900Å = Short-pass, hard-coated on the glass substrate indicated below, blocked to 1.1 micron, 65% or better peak transmission, MgF2 Coated on glass side. Glass substrate to be cemented combination of Schott GG 385 and either Hoya GM-500 or Hoya C-500 (whichever will adequately suppress the red leak). Total thickness to be 3mm as with the other items.