This section lets you go through some of the fitsblink
functions without reading the rest of the manual, just to get some
overview of the available functions.
Apart from a working fitsblink
program you also need the
example images which can be found on the fitsblink
home page.
Un-tar the file by typing tar xf examples.tar
. A directory
named fitsblink_examples
will be created and you will find
there the following files:
98kd3r5-98kd3r6.inp 98kd3r5.dat 98kd3r5.fts.gz 98kd3r6.dat 98kd3r6.fts.gz coordinates
Go to the fitsblink_examples
directory and start
fitsblink
. If the $HOME/.fitsblinkrc
file does not
exist yet, fitsblink
will complain. Just press OK
button and from the Astrometry menu choose the
Settings item. Set all of the settings and save them by
pressing the Save button. Next time you run fitsblink
it should not complain anymore about the missing parameter file.
98kd3r5.fts.gz
file from the file selector. The image will be
loaded and displayed in the blink window. Repeat this procedure with
the 98kd3r6.fts.gz
file. Now you have two images in the memory
and you can blink them just by pressing the Blink button.
The images will be alternately displayed on the screen. You can
adjust blinking frequency with the Delay counter. You
noticed that the images are not aligned perfectly. So, center a star
in the left small window with the magnified image and double-click on
it. Four cursor buttons will appear. Click on them until small
images are aligned and then press the button with a blue circle. The
images will be aligned now. If you look for a moving objects, you
will find one right to the center of the screen. To stop blinking,
press Blink again.
As soon you detect stars, you can also get their positions by pressing
the RIGHT mouse button when you are close to one of the DETECTED
objects. A window with a magnified part of the image around the
object position will appear. You will get object x and ycoordinates, as well as object intensity, all in pixel units. If the
WCS values are present in the image header or if you made a successful
match with catalog stars, you will also see the object's celestial
coordinates. For the example image 98kd3r5.fts.gz
the
coordinates of the moving object are:
Detection method | Catalog | RA | Dec. |
GSC 1.1 | 14:50:00.61 | 00:20:26.9 | |
GSC 1.1 + USNO SA 1.0 | 14:50:00.61 | 00:20:26.7 | |
USNO SA 1.0 | 14:50:00.60 | 00:20:26.6 |
There is another way to get object coordinates: choose the Do astrometry item. You will see the cursor change shape into a cross. Now press the LEFT mouse button on a selected object. An astrometry report window will appear and if you are happy with the measurement, type in the object name and press Accept. For more details about this, see sections 12.3 and 12.4.
Another interesting feature of fitsblink
are markers. You
already saw them if you detected stars and matched them with a
catalog. You can find some examples of the use of markers in the file
98kd3r5-98kd3r6.inp
. From the command line run
fitsblink -i 98kd3r5-98kd3r6.inp
and see what happens.
This concludes the quick overview of the main fitsblink
functions.