Instrument

class msumastro.header_processing.feder.Instrument(name, fits_names=None, rows=0, columns=0, image_unit=None, trim_region=None, useful_overscan_region=None)

Bases: object

Telescope instrument with simple properties.

Parameters

namestr

Name of the instrument.

fits_nameslist of str

List of names by which the instrument is known in FITS headers

rowsint

Number of rows in an image produced by this instrument, including overscan.

columnsint

Number of columns in an image produced by this instrument, including overscan.

image_unitastropy.units.Unit

Unit of the image; default value is None

trim_regionstring

Region of the CCD that should be preserved after overscan subtraction. Should use FITS conventions for specifying slices (i.e. slice starts at 1, includes endpoint, and uses FITS NAXIS1, NAXIS2 for order of indices).

useful_overscan_regionstring

Complete specification of the region of the CCD actually useful for overscan calibration. This may (or may not) be smaller than the entire portion of the chip the manufacturer labels as overscan. Should use FITS conventions for specifying slices (i.e. slice starts at 1, includes endpoint, and uses FITS NAXIS1, NAXIS2 for order of indices).

Examples

Consider an image whose dimensions as given in its FITS header are NAXIS1 = 3085 and NAXIS2 = 2048 with an overscan region that begins at position 3073 along axis 1. The useful part of that overscan is from FITS column 3076 up to and including, 3079, and the full range of rows (NAXIS2). The correct overscan settings for this instrument are:

# Note not all of the overscan region is actually useful.
useful_overscan_region = '[3076:3079, :]'
# But the whole overscan region should be trimmed away in reduction.
trim_region = '[1:3073, :]'

Methods Summary

has_overscan(self, image_dimensions)

Determine whether an image taken by this instrument has overscan

Methods Documentation

has_overscan(self, image_dimensions)

Determine whether an image taken by this instrument has overscan

Parameters

image_dimensionslist-like with two elements

Shape of the image; can be any type as long as it has two elements. The order should be the FITS order, NAXIS1 then NAXIS2.

Returns

bool

Indicates whether or not image has overscan present.