Description
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SkyMap v1.3 is a shareware "Planetarium" program for Microsoft Windows 3.1 or
later. It will display a map of the sky as seen from any point on Earth for
any date between 4000BC and 8000AD.  Two different types of map can be drawn:
a "Horizon" map showing the observer's local horizon, and a "Sky Area" map
showing a detailed view of a small area of the sky.  You can "zoom in" on a
map to a practically unlimited extent, and rapidly scroll around it.

There are many planetarium programs available today.  Unlike some of these,
SkyMap makes no claims of blinding calculation speeds.  Instead, what SkyMap
concentrates on is accuracy.  SkyMap uses the most accurate methods available
to the author for all the calculations.  This accuracy makes SkyMap equally
suited for both the novice astronomer who just wants to know "what's that
bright object up there?" and the serious amateur or professional astronomer
who wants a detailed "finder chart" for a faint galaxy.  Examples of this
accuracy are:

 -  Planetary positions have a mean error of less than half a second of arc.
 -  Star positions are rigorously corrected for the effects of proper motion,
    precession, aberration, and refraction.  Planetary positions are corrected
    for aberration and diurnal parallax.

SkyMap carries out its calculations in as efficient as manner as possible,
but it never compromises accuracy for the sake of speed.  An increase in
speed can always be achieved by using a faster computer!  Having said all
that, the speed is still reasonable; on the author's 33MHz 486-based PC for
example, the horizon map, with default settings, is computed and drawn in
about 5 seconds.

The following information can be displayed on a map:

Stars:    SkyMap uses the SAO star catalog as the source of star data.
          The shareware version of the program comes with a database of
          15,925 stars down to magnitude 7.0; the registered version of
          the program is supplied with a much larger star database, up to
          and including the complete SAO catalog of 258,997 stars to
          magnitude 9.5 or so.  Stars can optionally be labelled with
          proper names, Bayer letters, or Flamsteed numbers.

Constellations: Constellation names, figures, and official IAU boundaries
                can all be displayed.

Planets:  The Sun, Moon, and the planets Mercury to Neptune can be displayed,
          labelled with their standard astronomical symbols.  The Moon is
          displayed with the correct phase and orientation.

Deep Sky Objects:  The complete RNGC catalogue of non-stellar objects is
                   available. The user can select between the Messier
                   catalogue or the complete RNGC catalogue, and can apply
                   detailed selection criteria, such as "display globular
                   clusters brighter than magnitude 11".

All types of object can be switched on or off with the click of the mouse,
making it easy to see exactly the information you want, without being
flooded with unwanted information.
          
Detailed information about any object can be obtained simply by clicking the
mouse on it.  In the case of planets, the displayed information includes
both positional (RA, Dec, Distance) and physical (Magnitude, phase,
light time, elongation, phase angle etc) information.

When you have a map as you want it, it can be printed on any type of printer
supported by Windows.  The printed map is not simply a copy of the screen;
it is printed at the full resolution of the printer.  Maps printed on a
laser printer compare favourably with high-quality star atlases such as
"Uranometria 2000".  Maps can be printed in either black and white or
colour.  If you have a colour printer you can select the colour of each
component of the map.

SkyMap can also display photographic images, supplied in the form of GIF or
Windows bitmap files.   Thousands of such images are freely available on
bulletin boards and commercial information systems such as CompuServe and
BIX.  This allows you to build up your own personal library of astronomical
photographs which, coupled with the map displays, really helps to bring the
sky to life.  Images can either be displayed manually, or can be linked
with specific objects and displayed by simply clicking on the object on
the map.


System Requirements
-------------------

SkyMap will run on any computer supporting Windows 3.1, although a fast 386
or a 486-based computer is strongly recommended.  A maths co-processor is
not essential, but again is recommended; SkyMap does a huge amount of
trigonometry, and use of a co-processor can speed the program up by a factor
of 10 or more!

SkyMap has been tested using the March beta of Windows NT, and no problems
were encountered.

For the display of photographic images, a video card capable of displaying
256 or more colours (simultaneously) is recommended.  Images CAN be displayed
on a standard 16-colour VGA display, but will generally look pretty terrible!

Maps can be printed on any printer supported by Windows.  Good quality maps
can be obtained even from a 9-pin dot matrix printer.

SkyMap's files require a total of 1.3MB of disk space.


SkyMap Files
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SkyMap is distributed as a set of three ZIP files.  These are:

    SKYMP13A.ZIP:   The program and documentation.
    SKYMP13B.ZIP:   Data files essential for SkyMap's operation.
    SKYMP13C.ZIP:   Optional data files.  These include the constellation
                    boundary and RNGC object databases.

In order to run SkyMap you MUST have SKYMP13A.ZIP and SKYMP13B.ZIP.
SKYMP13C.ZIP is optional.

Note: SKYMP13B.ZIP is a direct replacement for the SKYMAP1D.ZIP archive used
by previous versions of SkyMap.  If you currently have SkyMap 1.1 or later
you do NOT need to download SKYMP13B.ZIP.

All three archives have been created using PKZIP v2.04g.