Sky Plot Window
The Sky Plot ()
plots longitude/latitude positions onto the celestial sphere.
It can plot to a number of projections
(currently Sin, Aitoff and Plate Carrée).
See the Window Overview
for features common to all layer plots.
The positional coordinates are Longitude and Latitude, specified in degrees. When supplying them, you can specify an associated Data Sky System (Equatorial, Galactic, Supergalactic or Ecliptic2000). Note that this is the sky system of the data coordinates, not (necessarily) of the plot you want to see. To specify the coordinates you want the data to be plotted on, use the View Sky System option in the Projection tab of the Axes control. However, if you just want to view the data using the same system as the coordinates you are supplying, you can ignore leave these values as their default (both Equatorial) and no conversion will be done.
Navigation controls:
Dragging will attempt to keep the same sky position under the cursor. This is usually possible, but in the Sin projection if the mouse starts off on the sphere and moves off it, that can't happen, so the panning can be jerky in that case. This only happens at low magnifications.
In the Sin projection, the zoom will rotate the sphere as well as increase its magnification, so that the cursor can stay on the same sky position while north remains pointing upwards.
The sky plot offers the following plot controls:
The Axes control ()
is described in
the next subsection.