fitsblinkprogram accepts 16-bit two-dimensional FITS images. The program also reads the header and extracts the following information:
fitsblinktries the following things to calculate the correct time of mid-exposure:
To load an image, press the Load button. A file selector will
appear and you can navigate through directories to find the wanted
file. When you find it, double-click on it or select it and press the
Ready button. It is also possible to type in the file name.
Fitsblink loads either FITS images or gzipped fits images,
thanks to the CFITSIO library. After loading it tries to make an
automatic level adjustment so that stars exhibit good contrast
relatively to the background. This procedure may produce not so good
results for images with very bright objects or if some non-image data
is stored in the image area. You can help the computer by setting an
autolevel parameter described later in this manual. When the image is
loaded, it is scaled and transfered to an X Windows structure called
Pixmap for faster blinking operation. The original image data remains
in the memory.
Fitsblink can in principle read unlimited
number of images. You are limited by the available memory of your
computer and X terminal, of course.
There is an alternative method of image loading, which is particularly suitable when the images are first processed by some program which analyses the images, finds how are they shifted and identifies moving objects. You need to prepare a file with the following structure:
filename1 x_offset1 y_offset1 filename2 x_offset2 y_offset2 . . .
If you name this file eg.
test.inp, a command
fitsblink -i test.inp will load files named in the first column
and shift the images by the offsets given in the second and third
columns. The purpose of this is to have properly aligned images at
the moment they are loaded into memory.
Additionally, following every line with the file name it is possible to append a list of marker coordinates. For every marker you need to specify also its size and a word describing the object it represents. You can also specify a marker color and shape. There must be four, five or six white-space separated items in such a line, for example
filename1 x_offset1 y_offset1 45 100 5 asteroid red box 67 29 5 asteroid blue 87 216 5 nova filename2 x_offset2 y_offset2 . . .
The default color is
red and the default shape is
circle. More about markers in section 10. Do not
forget to press return in the last line of the batch file. For a
practical example, see the Quick tutorial section.