User manual

The four buttons giving access to the graphical tools to
measure distance, to draw by hand, to place tags or to
write text are always clickable. Choosing one of them
leads automatically to the creation of a plane “drawing”
on top of the stack. Graphical elements that will be
placed with the mouse in the view will be memorized in
this plane, with celestial coordinates, and will therefore
be visualised on other images
Selection and Move
Graphical additions created by one of these 4 tools can be selected (Select tool) and even
moved through a click/drag with the mouse. When they are selected, small green
handles appear around their limits.
Technical detail: When one or several elements are moved at the same time, one should
note that the displacement is computed on the celestial coordinates (RA, DEC) only for
the object that is underneath the mouse pointer, and it is only then propagated to the
other selected objects. Keeping the SHIFT key pressed will change this behaviour and
only movements in XY coordinates will be considered for all objects. Both techniques do
not give the same result, in particular when the objects to move are distant by more than
several degrees or close to the poles.
Some tips
 During a tag (“tag” tool), keeping the "SHIFT" pressed leads to the computation of a
centroid for the pixel values the closest to the clicked location and moves the tag to
the location found. This enables you to easily put a tag at the centre of a star;
 It is possible to have the location appear close to a tag. For this, select the tag of
interest and use the contextual menu (right click or CTRL click) and select “label the
selected objects”.
 For a drawing done by hand (“draw” tool), it is possible either to keep the mouse
button pressed in order to draw “continuously” or to click several times in order to
draw straight lines one after the other. In this last case, it is necessary to put the
mouse pointer out of the view in order to stop the drawing process, or to double-click
on the last point.
 In order to create a new plane, so that the graphical additions will not be in the same
graphical plane, it is mandatory to press the "SHIFT" key while activating the tool.
Image cut associated to the distance tool
When the double arrow, used to measure a
distance, has been selected in the view, the zoom
panel (bottom right of the main window) is
replaced by an “image cut” showing the pixel
values along the line measuring the distance. If
this line is moved around in the view, the plot
evolves as a function of the location in the image.
Furthermore, if you move your mouse over the
plot, a red horizontal line appears and gives the angular distance and the number of
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