IRAM Memo 2015-1 Extended support of sky spherical coordinates in CLASS

# IRAM Memo 2015-1
Extended support of sky spherical coordinates in CLASS

S. Bardeau, J. Pety
1. IRAM (Grenoble)
2. LERMA, Observatoire de Paris

March, 26 2015
Version 1.0

### Abstract:

Up to now, CLASS only supported natively the radio projection of the sky spherical coordinates. The main limitation of the radio projection is the absence of support of a projection angle. This could imply some approximation in the handling of On-The-Fly data with rotated scanning directions. CLASS now supports all the projections already supported in the GILDAS kernel, i.e., none (unprojected spherical coordinates), gnomonic, orthographic, azimuthal, stereographic, lambert, aitoff, radio, and sfl. This required the introduction of the MODIFY PROJECTION command, the modification of the MODIFY POSITION command, and the modification of the position header section in the CLASS Data Format. This memo describes all this in details.

Keywords: coordinates, (re)projection, CLASS Data Format

Related documents: CLASS documentation, CLASSIC Data Container

- Contents
- Goal
- The new Position section in the CLASS Data Format
- Support in CLASS
  - Fillers and variables
  - Commands
- Old Position section
- About this document ...