Technical data

Chapter 5 Starmap 19
5. Starmap
Autostar Suite provides a highly detailed and extremely accurate map of the sky that includes stars, planets, galaxies,
nebulas and other deep sky objects. The map has a number of selectable options that allow you to generate the map in
a way that best suits your needs. Once you have configured the starmap to your requirements, you can generate a high
quality hard copy version.
You can center the starmap on any star, deepsky object, or constellation you choose. Or you can set the center
coordinates to any Right Ascension and Declination values you desire.
The starmap is normally drawn as a spherical projection. That is, each object's position is calculated based on the
current Zenith viewpoint and is then mapped, or projected, onto a sphere. This results in a display that has the minimal
amount of distortion around the point of interest, but, it is more computationally expensive than the flat polar or
equatorial projections that are sometimes used.
All starmap plotting functions are implemented using 64 bit floating point numbers with 80 bit intermediate results.
This provides extremely accurate maps, even when the field of view is less than 0.00001 degree.
Previous View
Redraws the starmap using the previous field of view and Zenith coordinates. This is used as an 'Undo' function.
Redraw
Redraws the starmap. Occasionally, other windows drawn over the starmap may corrupt a portion of the map, or leave
some remnants over the starmap image. The Redraw function clears the map and renders a new map using all of the
current parameters.
Animate Starmap
The Animate Starmap command allows you to redraw the ephemeral objects (Planets, Comets and Asteroids) in rapid
succession while incrementing the date and time between each redraw. A trail is left behind the object as it moves.
To begin animation, first select the Step Time and the units, either days, hours, minutes or seconds, then press the
Start button. The starmap will begin updating the positions of all the ephemeral objects that were selected in the
Options dialog box. While the animation is running you may change the step time or the units, or change the
direction. Pressing the Stop button halts the animation, leaving the trails displayed on the screen. You may click on
any of the trails to determine which object produced the trail. Note that the position that will be displayed in Object
Description dialog box will show the coordinates of the object at the current date and time, NOT the date and time of
the position in the trail.
The Reverse option allows you to clear the display, draw the objects in their normal starting positions, then begin
animation from the last position calculated. This is useful when looking for conjunctions or occultations.