mirs_filters_20221225(No. 1)

• History
• View the diff.
• View the diff current.
• View the source.
• Go to Observing/mirs_filters_20221225.
  • 1 (2022-12-25 (Sun) 16:35:36)
  • 2 (2022-12-25 (Sun) 17:10:02)

Observing

Available Filters†

Available filters are shown in the table below. An ND filter with OD=1 is assumed to be used for observing in the 9.8-um band to avoid saturation.

Saturation limit†

Saturation limits are calculated as shown in the Table below. An ND filter with OD=4 may also be available. By using ND filters (not applicable for the J and H bands) or performing defocused observations, objects brighter than the flux densities below, although such observations require special care for calibration.

Sensitivity†

Noise-equivalent flux density for one exposure is calculated as shown in the figure below. Corresponding 1-sigma 1-sec sensitivity is also plotted. This calculation assumes aperture photometry with an aperture diameter of 2.5 times the FWHM of the PSF in the medium seeing condition (see here). Since readout noise (assumed 100e-/read) is the main noise source in short exposures, sensitivity improves with longer exposure times. PWV dependency is not significant in these bands. The truncation in the right edge of each band shows the longest exposure time before saturation except for the J band. The sensitivities of the L' and M' bands are significantly worse due to the ND filters and the strong absorption of the diamond window.