========== surveyinit ========== :Summary: Design hour angles calculated during survey initialization. :Naming Convention: ``surveyinit.fits`` :Regex: ``surveyinit.fits`` :File Type: FITS, 36 KB Contents ======== ====== ======= ======== =================== Number EXTNAME Type Contents ====== ======= ======== =================== HDU0_ WEATHER IMAGE Nightly dome-open fractions assumed to calculate available LST. HDU1_ DARK BINTABLE Summary of hour angle optimization for the DARK program. HDU2_ GRAY BINTABLE Summary of hour angle optimization for the GRAY program. HDU3_ BRIGHT BINTABLE Summary of hour angle optimization for the BRIGHT program. HDU4_ DESIGN BINTABLE Design hours angles for all programs. ====== ======= ======== =================== FITS Header Units ================= HDU0 ---- EXTNAME = WEATHER Nightly dome-open fractions due to weather that are are assumed when calculating the available LST per program, as an input to the design hour-angle optimization. Required Header Keywords ~~~~~~~~~~~~~~~~~~~~~~~~ ======== ====================================================== ==== ============== KEY Example Value Type Comment ======== ====================================================== ==== ============== NAXIS1 2556 int Length of dimension 1. FIRST 2019-01-01 str Date of the first tabulated night. YEARS 2007,2008,2009,2010,2011,2012,2013,2014,2015,2016,2017 str List of years averaged to calculate predicted dome-open fractions. START 2019-12-01 str Nominal survey start date used for hour-angle optimization. STOP 2024-11-30 str Nominal survey stop date used for hour-angle optimization. TWILIGHT F bool Was twilight included in the BRIGHT program schedule for optimzation? ======== ====================================================== ==== ============== Data: FITS image [float64, 2556] The HDU data consists of a 1D array of dome-open fractions estimated by averaging `historical weather data `__. The value at index ``K`` corresponds to the night of ``FIRST`` plus ``K`` days. Note that dome-open fractions are tabulated for an extended date range that covers the nominal survey dates but also commissioning and survey validation. Use `load_weather `__ to read the dome-open fractions as a 1D array, optionally sliced to a specified range of dates. HDU1 ---- EXTNAME = DARK Summary of hour angle optimization for the DARK program. Required Header Keywords ~~~~~~~~~~~~~~~~~~~~~~~~ ======= ============= ===== ===================== KEY Example Value Type Comment ======= ============= ===== ===================== NAXIS1 24 int length of dimension 1 NAXIS2 192 int length of dimension 2 ORIGIN -60.0 float Low edge of first LST histogram bin in degrees. ======= ============= ===== ===================== Required Data Table Columns ~~~~~~~~~~~~~~~~~~~~~~~~~~~ ===== ======= ===== =========== Name Type Units Description ===== ======= ===== =========== AVAIL float64 Histogram of available LST in the DARK program. INIT float64 Histogram of initial LST usage, before optimization. PLAN float64 Histogram of planned LST usage, after optimization. ===== ======= ===== =========== Histograms are normalized to the (dimensionless) units of sidereal hours per LST bin integrated over the survey. HDU2 ---- EXTNAME = GRAY Summary of hour angle optimization for the GRAY program. Required Header Keywords ~~~~~~~~~~~~~~~~~~~~~~~~ ======= ============= ===== ===================== KEY Example Value Type Comment ======= ============= ===== ===================== NAXIS1 24 int length of dimension 1 NAXIS2 192 int length of dimension 2 ORIGIN -60.0 float Low edge of first LST histogram bin in degrees. ======= ============= ===== ===================== Required Data Table Columns ~~~~~~~~~~~~~~~~~~~~~~~~~~~ ===== ======= ===== =========== Name Type Units Description ===== ======= ===== =========== AVAIL float64 Histogram of available LST in the GRAY program. INIT float64 Histogram of initial LST usage, before optimization. PLAN float64 Histogram of planned LST usage, after optimization. ===== ======= ===== =========== Histograms are normalized to the (dimensionless) units of sidereal hours per LST bin integrated over the survey. HDU3 ---- EXTNAME = BRIGHT Summary of hour angle optimization for the BRIGHT program. Required Header Keywords ~~~~~~~~~~~~~~~~~~~~~~~~ ======= ============= ===== ===================== KEY Example Value Type Comment ======= ============= ===== ===================== NAXIS1 24 int length of dimension 1 NAXIS2 192 int length of dimension 2 ORIGIN -60.0 float Low edge of first LST histogram bin in degrees. ======= ============= ===== ===================== Required Data Table Columns ~~~~~~~~~~~~~~~~~~~~~~~~~~~ ===== ======= ===== =========== Name Type Units Description ===== ======= ===== =========== AVAIL float64 Histogram of available LST in the BRIGHT program. INIT float64 Histogram of initial LST usage, before optimization. PLAN float64 Histogram of planned LST usage, after optimization. ===== ======= ===== =========== Histograms are normalized to the (dimensionless) units of sidereal hours per LST bin integrated over the survey. HDU4 ---- EXTNAME = DESIGN Optimized design hour angles for each tile in all programs. Required Header Keywords ~~~~~~~~~~~~~~~~~~~~~~~~ ======= ============= ==== ===================== KEY Example Value Type Comment ======= ============= ==== ===================== NAXIS1 16071 int length of dimension 1 NAXIS2 10 int length of dimension 2 ======= ============= ==== ===================== Required Data Table Columns ~~~~~~~~~~~~~~~~~~~~~~~~~~~ ==== ======= ===== =========== Name Type Units Description ==== ======= ===== =========== INIT float64 deg Initial hour angles before optimization. HA float64 deg Final hour angles after optimization. TEXP float64 s Irreducible exposure time due to dust extinction and airmass at the design hour angle. ==== ======= ===== =========== Each row of the table corresponds to one tile with indexing that matches ``desisurvey.tiles.Tiles``. Use `load_design_hourangle `__ to read the ``HA`` column as a 1D array. Notes and Examples ================== The histograms of available LST in each program are calculated by `get_available_lst `__. Hour angle optimization is performed by `desisurvey.optimize.Optimizer `__ and documented in `DESI-3060 `__.