An overview of the planned CCAT software system

Abstract

CCAT will be a 25m diameter sub-millimeter telescope capable of operating in the 0.2 to 2.1mm wavelength range. It will be located at an altitude of 5600m on Cerro Chajnantor in northern Chile near the ALMA site. The anticipated first generation instruments include large format (60,000 pixel) kinetic inductance detector (KID) cameras, a large format heterodyne array and a direct detection multi-object spectrometer. The paper describes the architecture of the CCAT software and the development strategy.Comment: 17 pages, 6 figures, to appear in Software and Cyberinfrastructure for Astronomy III, Chiozzi & Radziwill (eds), Proc. SPIE 9152, paper ID 9152-10

ORAC-DR: A generic data reduction pipeline infrastructure

“…orac-dr has been in use since 1998, running on four telescopes and ten instruments covering the submillimeter to the optical and imaging to IFUs. Prototype pipelines have also been developed for Gemini and ESO instruments to prove the inherent flexibility of the design (Cavanagh et al, 2003;Currie, 2004) and the CCAT project are considering adopting it (Jenness et al, 2014c).…”

Learning from 25 years of the extensible N-Dimensional Data Format

“…The structure was first developed for the asterix package and adopted directly into the NDF data model. The history was, by design, not expected to be parseable by application software; applications such as surf (Jenness andLightfoot, 1998, ascl:1403.008) did nonetheless use the history to determine whether a particular application had been run on the data, so that the user could be informed if a mandatory step in the processing had been missed.…”

“…Whilst the provenance handling works extremely well and is very useful for tracking what processing has gone into making a data product, the provenance information can become extremely large during long and complicated pipeline processing such as those found in products from ORAC-DR (Cavanagh et al, 2008;Jenness andEconomou, 2015, ascl:1310.001). There can be many thousands of provenance entries including some loops where products are fed back into earlier stages because of iterations.…”

“…There is a renewed interest in file-format choices for astronomy with discussions on the future of FITS (Thomas et al, 2014(Thomas et al, , 2015, projects adopting or considering HDF5 (Alexov et al, 2012;Jenness et al, 2014) and investigations into general purpose image formats such as JPEG2000 (Kitaeff et al, 2014). These discussions have provided an opportunity to consider existing astronomy file formats that are not as widely known in the community as FITS.…”

Spectroscopic analysis in the virtual observatory environment with SPLAT-VO

“…Every spectrum of HEROS ( Šlechta and Škoda, 2002) is more than forty five thousand points long covering about 4500 Å (in two channels). Upcoming instruments from sub-millimetre telescopes such as CCAT (Jenness et al, 2014c) may have a hundred thousand channels per spectrum and echelle spectra (like those from UVES (Dekker et al, 2000) or HARPS (Pepe et al, 2000)) may have as many as three hundred thousand points. Just downloading thousands of spectra takes a long time, but zooming on every spectral line to see it in detail and unzooming takes even longer, while consuming lot of memory.…”