Keck NIRES

Overview

This file summarizes several instrument specific settings that are related to the Keck/NIRES spectrograph.

PypeIt File

Here is some advice on how to setup your PypeIt Reduction File. First, run:

pypeit_setup -r absolute_path -s keck_nires -b -c A

where -b indicates that the data use sky subtraction and the calib, comb_id, and bkg_id columns are added to the Data Block. See pypeit_setup and A-B image differencing for the syntax used for the data in these columns and how PypeIt uses them.

Here is an example of the Data Block of the PypeIt file:

# Data block
data read
 path raw/
              filename |         frametype |               ra |               dec |       target | dispname |    decker | binning |              mjd |          airmass | exptime | dithpat | dithpos | dithoff | frameno | calib | comb_id | bkg_id
NR.20201128.22795.fits |  arc,science,tilt | 25.8722004481703 | -1.77957177216147 | eris_28 0620 |     spec | 0.55 slit |     1,1 |  59181.263841269 | 1.13659692763023 |   300.0 |    ABBA |       A |     5.0 |      49 |     1 |       1 |      2
NR.20201128.23132.fits |  arc,science,tilt | 25.8702924043135 | -1.77752676502195 | eris_28 0620 |     spec | 0.55 slit |     1,1 | 59181.2677371023 | 1.12734707860924 |   300.0 |    ABBA |       B |    -5.0 |      50 |     1 |       2 |      1
NR.20201128.23467.fits |  arc,science,tilt | 25.8702636585777 |  -1.7775294833213 | eris_28 0620 |     spec | 0.55 slit |     1,1 | 59181.2716109449 | 1.11888914544008 |   300.0 |    ABBA |       B |    -5.0 |      51 |     1 |       2 |      1
NR.20201128.23803.fits |  arc,science,tilt | 25.8720347222654 | -1.77964895855717 | eris_28 0620 |     spec | 0.55 slit |     1,1 | 59181.2754992551 | 1.11131755069033 |   300.0 |    ABBA |       A |     5.0 |      52 |     1 |       1 |      2
NR.20201128.07158.fits |      lampoffflats |             58.0 |              45.0 |      unknown |     spec | 0.55 slit |     1,1 | 59181.0828553894 | 1.41291034446565 |   100.0 |    NONE |    None |     0.0 |      21 |   all |      -1 |     -1
NR.20201128.07382.fits |      lampoffflats |             58.0 |              45.0 |      unknown |     spec | 0.55 slit |     1,1 | 59181.0854467088 | 1.41291034446565 |   100.0 |    NONE |    None |     0.0 |      22 |   all |      -1 |     -1
NR.20201128.07496.fits |      lampoffflats |             58.0 |              45.0 |      unknown |     spec | 0.55 slit |     1,1 | 59181.0867630282 | 1.41291034446565 |   100.0 |    NONE |    None |     0.0 |      23 |   all |      -1 |     -1
NR.20201128.05431.fits |   pixelflat,trace |             58.0 |              45.0 |      unknown |     spec | 0.55 slit |     1,1 |  59181.062862681 | 1.41291034446565 |   100.0 |    NONE |    None |     0.0 |      11 |   all |      -1 |     -1
NR.20201128.05549.fits |   pixelflat,trace |             58.0 |              45.0 |      unknown |     spec | 0.55 slit |     1,1 | 59181.0642262227 | 1.41291034446565 |   100.0 |    NONE |    None |     0.0 |      12 |   all |      -1 |     -1
NR.20201128.05665.fits |   pixelflat,trace |             58.0 |              45.0 |      unknown |     spec | 0.55 slit |     1,1 | 59181.0655779588 | 1.41291034446565 |   100.0 |    NONE |    None |     0.0 |      13 |   all |      -1 |     -1
data end

frametype is automatically assigned to each frame using the values of various header keywords, see Automated typing of NIRES frames. The dither pattern, position and offset associated to each fame is reported here. PypeIt tries to automatically set the calib, comb_id, and bkg_id using the dither information (see Automated sorting of Keck/NIRES frames by instrument configuration); however, the user can edit these columns according to the preferred reduction.

Calibrations

Flat Fielding

The NIRES calibration GUI/scripts provide the option to take flats with the lamps off. PypeIt is able to recognize those frames and it will assign them the lampoffflats frame type. Whenever lampoffflats frames are identified in the PypeIt file, PypeIt will subtract them from the frames taken with the lamps on before creating the Edges and Flat frames. The user is responsible for ensuring that the lampoffflats frames in the PypeIt file have the same exposure times as the trace and pixelflat frames.

Additional Reading

Here are additional docs related to Keck/NIRES. Note all of them are related to the development of PypeIt for use with NIRES data: