SkyMap Pro Sample 2


Close-up Views of the Sky

The first sample showed a "planetarium"-type view of the sky, drawn on a grid of altitude and azimuth lines, showing only bright stars and constellation figures. That's fine for getting an overall idea of "what's up" for a particular time and date, but as astronomers we're more often interested in seeing a close-up view of a small part of the sky.

Starting from the first sample, we hold down the left mouse button and draw a "selection rectangle" around a part of Taurus. SkyMap Pro redraws the map to only show that part of the sky:


Region of Pleiades


Because the field of view is a lot smaller, SkyMap Pro has now automatically switched to displaying the map on an RA/dec coordinate grid, and is displaying stars as faint as magnitude 9 (as shown by the "S:9.0" indicator on the status bar). Notice that bright stars are now labelled, some with Greek letters, others with numbers, and still others with variable star designations.

We're also now seeing some "deep sky objects" on the map - in this case, a number of "open clusters", indicated by the green dotted circles. The large circle represents the "Hyades"; the smaller circle at the top left of the map is the much smaller open cluster "NGC 1647" (as shown by the label "1647" beneath it).

The white dotted lines in the lower left part of the map indicate a constellation boundary; in this case, a portion of the boundary between Taurus and Orion.

The map shown above is typical of what will be seen in a good printed star atlas, but with SkyMap Pro we can do much, much better! Let's suppose we decide to take a closer look at the open cluster NGC 1647 - the small open cluster at the top left of the above map. We draw our selection rectangle around it using the mouse, and SkyMap Pro immediately shows us a "zoomed in" view of that specific part of the sky:


Close-up view of NGC 1647


We are now seeing stars to magnitude 13 - far "deeper" than the best printed star atlas! The group of stars comprising the open cluster is easily seen within the dotted circle representing the cluster, and we also now see a number of faint galaxies in the lower part of the map.

Because we're now looking at a very small part of the sky, a coordinate grid is of limited use; it's much more helpful to be able to directly see units of "angular measurement" on the map. To help us to this, a "scale line" representing a sample length (here, 30 arc minutes) has been drawn at the lower right of the map.

Last Modified May 10, 2006