Coordinate Systems

The topics below discuss how Mira works with the coordinate systems of images and plots.

Coordinate System Topics


World Coordinate System

describes the FITS World Coordinate System.

Image Coordinate System

describes how coordinate systems are used for measuring distances, angles, centroid positions, and other quantities in images.

Pixel Coordinate Definition

describes how pixels are referenced and counted in image coordinates.

Subpixel Coordinate Definition

describes how fractional pixels are counted in image coordinates.

Angle Measurement Definition

describes how angles are measured for different coordinate systems.

Plot Coordinate Systems

describes how coordinate systems are used in displaying 1-D data.

Plotting in World Coordinates

describes how 1-D plots implement the image coordinate system.

Image Display Orientation

describes how rows are counted in different image formats.

FITS Image Orientation

describes how FITS format images are oriented for display.

Image Coordinate Display

describes real-time readout of the image pointer (crosshair).

Adjusting the Image Cursor

describes how to adjust and position the image cursor.

World Coordinate System Keywords

describes header keywords used to describe world coordinate systems.

 Coordinate Calibration Commands

The topics below discuss tools used for calibrating and working with world coordinate systems


Astrometric Calibration

creates a "plate solution" for an image using the coordinates of at least 3 marked stars.

Set Arcsecond Scale

assigns an arcsecond scale to an image.

Set Equatorial Scale

assigns a simple equatorial coordinate system of (right ascension, declination) to an image.

Delete WCS

deletes any type of World Coordinate System scale from the image, reverting it to the (column,row) system.

WCS Keywords

lists the values of world coordinate system keywords in the image header.

Go To Coordinate

moves the image cursor to a target position, or loads the current position in either pixel or world coordinates.

Related Topics

Contents, Measuring Images