Leak in 7.466µm filter fixed

This afternoon we took some data intended to verify that the leaking of third-order light through the 7.466µm filter had been fixed by the replacement of the BaF2 blocker used in CD8 with CaF2.

Looking back at CD8 in the lab book, found a reference to leaking third-order light in B_10_08_18/b222.fits.  Here's the image.

It's apparent that there are two overlaid patterns of orders....the more widely-spaced set shouldn't be there.

Today we went back to the same echelle angle and filter, this time using the pinhole:

The pinhole makes for narrow orders but less overall light...the integration time was increased bay a factor of three over that for b222 to check whether there might be faint leakage  between the orders, but none appears.  Looks like the CaF2 did the trick.