Science Operations

Baseline Calibrations

Standard wavelength calibration and flat fielding for MODS1 and MODS2 obtained with each instruments own internal calibration unit.  Baseline calibrations include biases, comparison lamp spectra, slitless and thru-slit continuum lamp flats, internal imaging flats, and spectrophotometric standards. Calibration scripts sets the PARTNER and PROPID as CALIBRATION, and sets the PI_NAME as ALL.

Flat fields appear to be very stable for a run; calibrations do not have to be taken daily. It has been noted that a single set of master pixel and slit flats works for an entire week-long run without issue. Quantifying the stability of the calibrations is coming soon.

Calibration Observations are included as part of the MODS OT Library.  Calibration scripts generated from v10.24 of the library are in /home/modseng/modsScripts/modsCalibs_OT/.   Note that the calibration units for MODS1 and MODS2 differ slightly so the calibration times have been tailored for each instrument within the templates and are not identical for MODS1 and MODS2.  Scripts for spectrophotometric standards are in the OT library and also in /home/modseng/modsScripts/modsSpecPhot.

MODS Calibration Summary

Each row of the table below gives the different baseline calibrations for each observing mode for MODS and mods of use.
 

Observing    Mode

Standard Instrument
Configuration

Biases

Arcs

Flat Fields

Twilight Sky Flats

Spectro-photometric Standards

Spectral Slit Flats Pixel to Pixel Slitless Flats Imaging Flats

Grating Long-slit Spectroscopy

Binning: 1x1ROI: 8Kx3K
Dual About Biases  Arcs taken with:
LS560x0.6 standard
About Arcs
To be taken with each long-slit used

About Long Slit Flats

About Pixel to Pixel Slitless Flats N/A About Slitless Twilight Flats
(not recommended)
Spec Phot Standards 
Red
Blue
Grating

Multi-Slit
Spectroscopy

Binning: 1×1

ROI: 8Kx3K

Dual About Biases Arcs and Flats template to be adjusted for mask
About MOS Arcs
About MOS Flats
About Pixel to Pixel Slitless Flats N/A About MOS Slitless Twilight Flats
(not recommended)
Spec Phot Standards
Red
Blue
Prism

Long-Slit
Spectroscopy

Binning: 1×1

ROI: 4Kx3K

Dual About Biases Arcs taken with:
LS560x0.3 standard
About Arcs
About Long Slit Flats Prism slitless flats saturate and are not to be used N/A About Slitless Twilight Flats
(not recommended)
Spec Phot Standards
Red
Blue
Prism

Multi-Slit
Spectroscopy

ROI: 4Kx3K

Binning: 1×1

Dual About Biases Arcs and Flats template to be adjusted for mask
About Arcs
About Flats
Prism slitless flats saturate and are not to be used N/A About MOS Slitless Twilight Flats
(not recommended)
Spec Phot Standards
Red
Blue
Imaging ROI: 3Kx3K

Binning: 1×1

Dual About Biases N/A N/A N/A About Imaging Pixel to Pixel Flats Imaging Twilight Flats
(recommended)
N/A
Red
Blue