- Aug 2006: Realised JH (and maybe IJ) need blocking filters.
NIGHTTIME CHECK ON POSSIBLE BLOCKER FOR IJ GRISM.
2006-08-29: Took flat/arc/standard obs of BS6975 (A3V, 6.57mag) with the IJ grism and the PK50 and J-spectral blockers. Peaked up spectra after acquisition (wouldn’t need UPICK correction with J-spectral). Comparison spectra are shown below.
NOTE: The J-spectral blocker cuts off at 0.96 micron, so arc lines seen below this wavelength are missing in the J-spectral data because of the filter. Otherwise, both sets of data look very similar; maybe a 2nd-order arc line at 1.40um that shouldn’t be there…. Throughput may be worse with J-spectral.
Comparison of IJ Spectra with PK50 and J-spectral blockers
NIGHTTIME COMPARISON OF IJ WITH SHORT-J AND LONG-J
2006-09-01: Took flat/arc/standard/source data on WR140, a Wolf-Rayet star will lots of broad, strong line emission. Data taken through the IJ grism, again using PK50 and the J-spectral filter as a blocker. We also took data through the short-J and long-J grisms. In all four data sets the various bumps and features match well. There is no evidence of additional lines coming through in 2nd order…