Conventions#

Units#

[[TODO INTRO]]

We therefore have the following conventions established to deal with the many differing unit conventions.

For internal computations and exchanges, we only use pure SI base units. All quantities are in SI units, unless explicitly described otherwise. Some common quantities are described below. Please note that often Astropy will condense these units automatically so combinations of these units may look weird.

  • Time: s

  • Length: m

  • Wavelength: m

  • Pressure: Pa

  • Flux density per unit wavelength: W m^-2 m^-1

  • Photon: ph

  • Pixel: pix

  • [[spaxel]]: voxel

  • Angles: rad

  • Solid angle: sr

  • Information: bit

This is beneficial in that we do not need to deal with unit clashes. We also allow Astropy to handle quite a few unit conversions behind the scene. However, as developing Lezargus, care must still be taken into account. The ultimate idea being that units within Lezargus are all self-consistent, with conversions happening at input and output. Unit conversions are easily done using Astropy using the list above as common equivalencies.

Of course, we will provide all of the needed conversions without the need for heavy user interactions. Usually these conversions are input via a GUI or configurations. FITS header information also is considered to be post-conversion and so is more easily accessible to other users.