MODS Observing Planning Tools
Updated: 2013 May 10
This page provides access to web-based MODS observing planning tools and
calculators.
- Tools:
- MODS1 Instrumental Sensitivity - May 2013 (15k PDF)
- Imaging Exposure Time Calculator
- Target Visibility Calculator
- Differential Atmospheric Refraction Calculators
This is a work in progress, more tools are on the way...
Notes
- Target magnitudes are assumed to be in standard SDSS AB magnitudes for
point sources, and AB mag/arcsec² for extended sources.
- If target magnitude box is left blank, no calculation is done for that
filter (but 0 will mean 0.0 mag; the box must be empty).
- If either the "SNR for ExpTime" or "ExpTime to get SNR" boxes are
left blank, that calculation will be omitted.
- Airmass must be 1.0 or larger up to 10.
- Seeing should be >0.3-arcsec. It is ignored for extended-source
calculations.
- Moon Age 0d = New Moon, 14d = Full Moon, 7d = First/Last Quarter Moon.
Spectroscopic Sensitivity
- MODS1 Instrumental Sensitivity - May 2013 (15k PDF)
For a given date, computes the hourly visibility (hour angle, airmass,
parallactic angle, and Moon elevation) of a MODS target from the LBT,
including a plot of elevation versus time. Based on John
Thorstensen's skycalc program.
John Thorstensen's
JSkyCalc program can be very helpful for visualizing your
time-and-the-sky constraints; the executable jar file can be
downloaded from John's GitHub repository
Note that JSkyCalc is
also installed on the LBT observing workstations for use on the mountain.
MODS does not have an Atmospheric Dispersion Corrector (ADC), so
orientation of the slit at or near the parallactic angle is essential in
order to mitigate slit losses due to atmospheric dispersion, especially
at the UV end of the MODS blue channel.
These tools will help you determine hour-angle restrictions and choice
of slit position angle to compensate for atmospheric dispersion for your
targets.
Calculates the parallactic angle, elevation, airmass, and
along-parallactic slit position angles of a target for a range of hour
angles.
Calculates a table of differential atmospheric refraction for a target
for wavelengths of 350-950nm over a range of hour angles and choice of
slit position angle, width, and AGw guide camera filter, and generates a
plot of the atmospheric dispersion track relative to the slit.
Updated: 2020 Dec 21 [rwp/osu]
