Python API for Startlight Xpress CCD (sxccd)

Okay, let's face it. Startlight CCDs ship with a easy-to-use GUI software Startlight Live, which has an infamouse bug: it crashes when the image is too large or exposure time is too long. For example, on my Mac BookPro, the longest exposure tiem I can do is 500ms with 2x2 binning. Not a chance for 1x1 binning even with 1ms exposure time.

I realized that Starlight has a very strict timeout setting, which is presumably 1 second. Once exposure + data transfer time exceeds 1 second, a time out of the USB communication between the software and the CCD occurs. That's why I never could take a image with exposure time longer than 500ms and/or with 1x1 binning mode. Speaking of binning, the software also has some bugs with binning, of which I haven't figured out the reason.

Here, I implemented some selected functions provided by SXCCD's USB API.

For example:

import sxccd


camera = sxccd.Camera()

# print out camera model
camera.model()

# print out firmware version
camera.firmwareVersion()

# retrive current camera parameters
params = camera.parameters()

# reset camera
camera.reset()

# echo
echo_result = camera.echo("Hello world!")
print( echo_result )

# Timed exposure
image = sxccd.readPixelsDelayed(exp_ms, width, height, x_bin=1, y_bin=1, x_offset=0, y_offset=0, verbose=False)

where exp_ms is exposure time in ms (1~65535), width and height are width and height in pixels to be read, respectively, x_bin and y_bin are bin nubmer for x and y axis, respectively, and verbose is the flag for verbose output.

Looking for automatic exposure? We have you covered. sxccd_image.py allows you to perform automatic multi-exposure and saves the images to HDF5 file.

python sxccd_image.py EXP_TIME [--delay DELAY] [--prefix PREFIX] [--number NUM] [--bin BIN] [--single-image]

EXP_TIME: exposure time in ms (1~65535)

DELAY: delay time in sec before the exposure process starts. Default: 0.

PREIFX: prefix of outout filename. Default is images. For example, if the exposure time was 10 ms, then the default output filename is images_000010.h5.

NUM: number of exposures to be performed. Default: 1.

BIN: number of bining. Default: 1.

If --single is given, the program saves every single image in /imgs dataset in the h5 file. Otherwise the program only saves the averaged image, which can be found under /avg dataset.