CCD Astronomy on Linux

These pages describe a number of facets of using astronomical CCD cameras for image acquisition and processing under Linux.

Introduction

For control of SBIG ST7/8/5C/237 series CCD cameras, the sbig-linux software provides low-level control of the camera. This is a library of routines that

Establish a connection with the camera
Return camera status
Control the fan, cooling and other features
Rotate a CFW6 or CFW8 color wheel, or the wheel in the 237
Set the tilt of the AO7 "adaptive optics" unit
Start exposures
Download exposures

This library is C code, and (because the camera control protocols are proprietary) does not include source.

For basic image acquisition, there is source for two simple, command-line based interactive programs. These utilize all the above functions, and allow saving files in FITS format.

View the documentation here.
Download via ftp.

Dataset and Image Processing under Linux

I am developing Linux software that allows for sophisticated image acquisition and processing. In particular, it allows Object Oriented conversational processing using the simple, but powerful, O-O scripting language Ezl .

Among the features of this software are:

Separate handling of 'scientific' datasets and their visualizations
Work either conversationally or with a Graphical User Interface (or both, simultaneously)
Does dataset operations, including statistical analysis, stellar profile fitting, centers of mass, bad-pixel propogation
Does visualization mappings, including profiled histogram equalization, median functions, deconvolution, log/gamma correction
Automate tasks, do complex analysis of the data.
Supports A07 tracking using a variety of algorithms.
Handle tracking and imaging acquisition simultaneously from SBIG dual-CCD cameras

and, lots more.

The EZL programming language is simple, like BASIC, but considerably more powerful. With it, you can:

Interact conversionally
Create objects, such as image-datasets, visualization windows, vizualization filter sets.
Interactively control the CCD camera, or start up control windows (custom or standard) to do this
Store/Load datasets, image files, notes, or just about anything else to and from disk
Program your own methods to handle sophisticated analysis
Deal uniformly with all data, since everything in Ezl is an object.

Not deal with memory management: all memory is handled automatically for you, and is transparently garbage-collected. The language is fully "reflective", meaning you can find out everything there is about an object.

Language object classes include:

Numbers (64 bits worth)
Strings
Heterogenous multidimensional arrays that grow dynamically
Dictionaries (the basis of all data management in Ezl; Ezl has no 'variables', rather everything is an entry in some dictionary. Dictionaries have keys that are names, and are roughly analogous to variable names in other languages, and values which are roughly analogous to the values stored in variables in other languages.)
Truth values
Ranges of integers

Classes specific to the CCD imaging functions include:

Camera (Object for control of an SBIG CCD camera)
Dataset (CCD data, either acquired, loaded from file, or synthesized)
DatasetFilter (an object that processes data in a dataset)
ViewFitler (an object that is part of a pipe-line of visualization operations)
ViewWindow (window for setting up visualizations)
Selection (geometrical region of a dataset)

Here is some Ezl, to give you a flavor of conversational usage:

    /* create a new CCD camera object; this
       establishes a connection to the camera */
    c = new Camera()

    /* Set the camera's temperature regulation to 0deg C */
    c.SetCooling(0.0)

    /* Take an exposure using the tracking ccd, start
     * the exposure at the 4th image line, and
     * use 2x2 binning */
    my_exposure = c.Expose(CCD: "Tracking", Y: 3, Binning: 2)

    /* Invoke 3-neighbor median statistical processing
     * on the dataset, the result is a Dictionary with
     * various entries */
    lp_stats = my_exposure.Median3Max()

    /* In Ezl, any/everything can be printed */
    Print(lp_stats)

    /* Call my own procedure for flat fielding */
    my_exposure.FlatField()

    /*  If there is sufficient signal, save the image */
    IF lp_stats.Max - lp_stats.Min > 20000 THEN
        my_exposure.Write("NGC200")
    END

CCD Astronomy on Linux

Introduction

Dataset and Image Processing under Linux

Other Links