The new version of
GMMPS is a major
improvement over its
predecessor. Driven
by the need to ac-
commodate the new
GMOS-N detectors,
and in particular F-2,
the source code was
overhauled in many
ways to make it more
instrument-indepen-
dent and modular.
These changes come with greater stability,
internal consistency checks, many bug fixes,
and new features including the following:
• Safe placement and proper motion check
of acquisition stars;
• No more external band-shuffling files;
• Slit placement area accurately measured
(no more lost slits);
• Consistent visualization of band- and mi-
cro-shuffling mask designs;
• Spectral packing in micro-shuffling mode,
allowing for much greater slit density;
• Allowing tilted slits in micro-shuffling
mode (e.g., for faint strong lensing arcs);
• Display of required Phase II parameters for
the Observing Tool;
• Extensive integrated help web pages, also
available online here;
• Simpler and more robust source code in-
stallation.
In addition, accurate mathematical models of
both GMOS spectrographs have been inte-
grated (see the GMOS WaveMapper item on
next page). They predict accurately (within a
few pixels) where a certain wavelength will
fall onto the detectors — as a function of slit
position, central wavelength, and grating. Us-
ing these models and full optical throughput
curves, the length of the spectra and their
location are accurately known in advance, al-
lowing users to perform the following tasks
(among others):
July 2017
• Overlay wavelength grids and display 2nd
order contamination (Figure 5);
• Display individual wavelengths and atomic
line series (optionally redshifted);
• Display the wavelength intervals cut out by
the detector gaps;
• Interactively adjust the central wavelength
to preserve spectral features of interest
(Figure 6).
The new version of GMMPS allows users to
design the masks in a more transparent and
robust manner, and provides a quantitative
and accurate preview of any data obtained.
New: WaveMapper — Modeling
the GMOS Spectrographs
The GMOS WaveMapper is a new and highly
useful tool that predicts accurately where a
GeminiFocus
Figure 5.
GMMPS optionally
displays a wavelength
grid (yellow numbers) for
each spectrum, including
the wavelength interval
(bright blue) cut out by
the detector gaps. Second
order contamination can
also be shown (orange
shaded area).
Figure 6.
The central wavelength
(CWL) of GMOS can now
be adjusted interactively,
guided by the wavelength
displays (see Figure 5).
Optionally, individual
wavelengths and atomic
line series can also be
shown.
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