NIRSPEC Echelle Format Simulator (EFS GUI)

The NIRSPEC EFS GUI is both a planning and operational tool. It can be used off line to plan spectral setups and observing sequences of the instrument, and write out scripts which can be later loaded into the operational NIRSPEC EFSgui and executed real time when running the instrument at WMKO.

NOTE: Use "Setup Only" to configure the instrument BEFORE running any calibrations (e.g. Lamps Only) or taking data on sky (e.g. Object/Bright Object Only).

EFS
To use the EFS:
Obs. Mode
Select from:
  • Setup Only: Configure NIRSPEC only (always do this for each new configuration first)
  • Lamps Only: Take calibration frames only
  • Object Only: Take on-sky data only
  • Bright Object Only: Take on-sky data only of Bright Sources (where nod patterns are slightly offset from "Object Only")
Nod Pattern
All nod patterns assume you are starting from the slit center. This option is ignored for "Setup Only" and "Lamps Only". Nod Patterns are described in detail below:
  • Stare: Do not move the telescope between exposures
  • Nod 2:
  • Nod 3:
  • Nod 4:
  • ABBA (most common & more efficient than Nod 4):
  • Nod off:
  • User
Number of Reps
Select how many times the Nod Pattern is executed. This is almost always set to "One".
Spec. Mode
Select from:
  • High Res: Cross-dispersed echelle spectroscopy (R~25,000)
  • Low Res: Grating spectroscopy (R~2000)
Slit
Select from (values are arcseconds):
  • 12 arcsecond high res slits: 0.14,0.29,0.43,0.58,0.72 arcsec wide
  • 24 arcsecond high res slits: 0.29,0.43 arcsec wide
  • 42 arcsecond low res slits: 0.38,0.57,0.76 arcsec wide
Filter
Select your filter:
  • NIRSPEC-1 through -7 are custom spectroscopic filters that have higher throughput than the standard photometric filters
  • In general, use KL for L-band spectroscopy
  • In general, use M-wide for M-band spectroscopy
Blocking:
Select "Thin" for NIRSPEC-1 through -7 inclusively due to thermal leaks
Plot Filter Profile
You may compare filters via this popup
Bad Pixel Mask:
Not used
Echelle:
The EFS will pick an echelle angle for you based up Spec. Mode and Filter. You may change it by typing in this box, or clicking and dragging the orange box on the echellogram.
Cross Disp:
The EFS will pick a cross disperser angle for you based up Spec. Mode and Filter. You may change it by typing in this box, or clicking and dragging the orange box on the echellogram.
Lock Mechanisms
Selecting "Lock" will prevent disable changes to "Spec. Mode", "Slit", "Filter", "Echelle", and "Cross Disp".
Object/Itime/Coadds
These options are greyed out for "Setup Only" or "Lamps Only". You must enter carriage return (or enter) after entering a new value for Object, Itime, or Coadds.
GO
Click this to execute your commands
ABORT
You may safely exit an observing script via the "ABORT" button. You will not abort the exposure in progress but you will have to recenter your object after the abort completes.
Nod Pattern Details
  • All nod positions avoid the exact slit center where targets are aquired.
  • All nod patterns except "Nod Off" and "User" are hard-coded into the EFS.
      The beams will be separated by a size depending on the selected slit:
    1. 12 arcsecond slit: 6 arcseconds (3" for Nod 3 & Nod 4)
    2. 24 arcsecond slit: 12 arcseconds (8" for Nod 3, 6" for Nod 4)
    3. 42 arcsecond slit: 15 arcseconds
  • Stare: Do not move the telescope while taking data
  • Nod 2:
    1. Nod telescope up/right
    2. Take a spectrum
    3. Nod telescope down/left
    4. Take a spectrum
    5. Return to slit center
  • Nod 3:
    1. Take a spectrum near center position (1.5" away)
    2. Nod telescope up/right
    3. Take a spectrum
    4. Nod telescope down/left
    5. Take a spectrum
    6. Return to slit center
  • Nod 4:
    1. Nod telescope up/right
    2. Take a spectrum
    3. Nod telescope down/left
    4. Take a spectrum
    5. Nod telescope up/right
    6. Take a spectrum
    7. Nod telescope down/left
    8. Take a spectrum
    9. Return to slit center
  • ABBA (most common & more efficient than Nod 4):
    1. Nod telescope up/right
    2. Take a spectrum
    3. Nod telescope down/left
    4. Take a spectrum
    5. Take a spectrum
    6. Nod telescope up/right
    7. Take a spectrum
    8. Return to slit center
  • Nod off:
    1. Take a spectrum at center position
    2. Nod telescope off the slit according to keywords "node" and "nodn"
    3. Take a spectrum
    4. Return to slit center
  • User (allows defining a custom nod sequence)
      Before selecting this option, you must define a nod sequence file that will be of the form: -1.0 -4.0 0.0 4.0 1.0 in /home/nspec#/
    1. Nod telescope down/left 1 arcsecond
    2. Take a spectrum
    3. Nod telescope down/left 4 arcseconds
    4. Take a spectrum
    5. Nod telescope down/left 0 arcseconds (telescope won't move)
    6. Take a spectrum
    7. Nod telescope up/right 4 arcseconds
    8. Take a spectrum
    9. Nod telescope up/right 1 arcsecond to return to slit center