History


SkyMap Release History
----------------------

01-DEC-96 v3.1

New features added:

Horizon map:

Previously the Horizon map was always scaled to fill a full-screen
window, and in a smaller window the scroll bars could only scroll
within this original area. This made the scroll bars pretty useless
and wasted screen space. The Horizon Map now has no scroll bars -
the map is always scaled to fit the specified view into the size of
the window and the map can be scrolled around the whole sky using the
cursor keys. This is a GREAT improvement.

Added a "Z" (Zenith) button to the toolbar to display a map of the
whole sky.

When the "Search" menu is used to search for an object, and the object
is not currently above the horizon, the program previously simply said
" is not currently above the horizon". It now tells you the
time that the object will next rise, or that the object never rises
from the current location.

Area map:

The area map previously displayed a fixed area and could zoom in and
scroll only within that area. It is now possible to scroll the area map
around the sky freely using the cursor keys - this has some impact on
speed, but adds a great deal of flexibility; for example you can now
draw an object track, then scroll the map so the track is displayed in
the best position.

All major nebulae are now shown with the correct outline shape, rather
than using a standard symbol such as a square or circle.

Right clicking on a planet, comet, or asteroid now
gives the user the option of "locking onto" that object. Once the view
is locked onto an object, changing the time or date will keep the map
centred on that object. A button on the toolbar releases the lock.

A new button on the "Lines" tool palette now switches on or off display
of a "compass" showing the directions of north, south, east and west on
the map. This makes it easy to see the orientation of the map -
especially useful on printed maps.

General:

Reorganized the menus into what is hopefully a more consistent layout.
The layout now is:
File: All "global" configuration parameters.
View: Items which determine which map is drawn.
Options: Items which determine the appearance or layout of
map features.

The on-line help system has been completely revised, updated, and
expanded. We now make use of the Windows 95 help engine and have
a "table of contents" page making the whole system a lot easier to
use.

The size, position, and state of the SkyMap window is now automatically
saved between runs of the program.

Previous versions of SkyMap saved map files with an extension of
".map". This is a relatively common extension used by other applications
such as linkers, so the map extension has been changed to ".smp".

SkyMap now properly interacts with the Windows 95 "shell". Double
clicking on a SkyMap map file in the "Explorer" will run SkyMap and
load the map; dragging a file to the printer will run SkyMap and
print the map.

All the multi-page (tabbed) dialogs now remember which page they
were on when last used, and reopen on the same page. This is very
useful when making frequent changes to the same setting.

A new "Telescope" menu allows SkyMap to control and interact with
the popular Meade LX-200 computerized telescope.

Split the "Objects" palette into two halves - Objects, and a new
"Lines" palette which has all the buttons for switching on and off
lines and coordinate grids.

Added a "scale line" option to the "Lines" palette. When switched on,
a line showing the scale of the map is displayed in one corner of the
map. Especially for Area maps showing a small region of the sky, this
can be preferable to displaying a coordinate grid, and certainly
results in a "cleaner" map.

The "Observer" dialog now has a "home" button which resets the default
location and time zone information.

The planet information dialog for Mecury and Venus now displays a
picture showing the phase and orientation of the planet.

All the information dialogs now display the chart on which the object
is located in the popular "Uranometria 2000" star atlas.

Deep sky objects which have a "popular name" (eg "Orion Nebula",
"Whirlpool Galaxy") are now labelled on the map with that name
rather than a catalog number. These names are read from a new data
file "saclabel.sky".

Most deep sky objects are NGC objects, and the "NGC" labels clutter up
the map. To make maps "cleaner", NGC objects are now labelled on the map
without the "NGC" prefix - eg "NGC 1234" is now labelled as simply
"1234", although right clicking on it will still show "About NGC 1234..."
as a menu option.

A new "Phases of the moon" item on the "Tools" menu displays the times
of new moon, first quarter, full moon and last quarter. Buttons on the
dialog allow you to move backwards and forwards through the lunar
months, and a month/year area of the dialog allows a different date
to easily be entered. a "Copy" button copies the displayed information
to the Clipboard for pasting into other applications.

The list of file extensions which SkyMap uses to look for a picture
of an object when you right click on the map can now be edited in
the File/Preferences dialog. Although the "SkyImage" viewer supplied
with the program can still only handle the same image formats as
before, if you use a more powerful replacement viewer (eg the excellent
"PaintShop Pro") you can now view additional picture formats such as
JPEG and TIFF simply by adding the appropriate extensions to the list.

The constellation full or abbreviated names option has been changed.
Previously it was a simple "full names" or "abbreviations" switch,
whereas now a field of view limit can be specified. If the field of
view is greater than the limit, abbreviated names will be shown,
otherwise full names will be shown.

The way that SkyMap uses the Hubble Guide Star Catalog CD-ROMs has been
very much improved. All the general GSC configuration parameters are now
on the File/Preferences dialog, and are "global" rather than specific to
one map. The CD-ROM is only accessed if the limiting magnitude is
increased beyond a specified "activation threshold", and it is no longer
necessary to specify separate magnitude limits for SAO and GSC stars.

A new "Lighting" option on the Options/Colour menu allows the colour of
the map background to optionally change with the time of day. Three
different map background colours can be set for night, twilight and day
conditions. The "twilight" colour can also optionally be used for night
conditions when the Moon is above a specified altitude and phase.

When the program starts up a "tip of the day" dialog is optionally
displayed, showing useful hints on using the program. This can
also be displayed from the Help menu.

Added new keyboard accelerators:
"A" = Toggle alt/az grid
"R" = Toggle RA/Dec grid
"L" = Toggle star labels
F5 = Decrease limiting magnitude

Changed the "zoom in" and "zoom out" toolbar button pictures; several
people commented that the previous symbols were rather cryptic.

When a menu is visible, the information panel of the status bar is
expanded to fill the entire bar. This makes it possible to read menu
item descriptions even when the map window is narrow.

A new "Status Bar" page on the "Preferences" dialog allows the user to
configure which items of information appear on the status bar.

Added new Alt/Az and RA/Dec panels to the status bar at the bottom of
the window. These show the coordinates of the mouse pointer as it
moves over the map.

Added new status bar panels to display a real time clock. Three different
clocks are available showing:
- Local mean time
- UTC
- Local sidereal time
All three assume that the machine's clock is set to local mean time.

When calculating the apparent field of view of an eyepiece/telescope
combination we previously used the simple formula:
true field = apparent field / magnification
We now use the more accurate formula:
tan(true field/2) = tan(apparent field/2)/magnification

Previously, when calculating times of rising and setting, SkyMap
first found the time of transit for the current day, then gave you
the rise time immediately preceding the transit, and the set time
immediately following it. This meant that the rise was often for the
previous day, and the set for the next day. We now always find the
time of rise and set for the current day.

Added new "DeltaT" data from 1996 "Astronomical Almanac".

The SAC deep sky object database has been upgraded from version 6.0
to version 6.2. This doesn't add any new objects, but corrects all
known errors.

Obsolete features removed:

Removed the "Zoom to" popup menu from the Horizon map's "View" menu.
The ease and speed of zooming in and out make it superfluous.

Removed the "Area Map..." item from the horizon map's pop-up menu.
It is always easier to drag a selection rectangle on the map.

Removed the "Recompute" item from the area map's pop-up menu. The new
method of drawing area maps makes it unnecessary.

Removed the View/Show... dialog from both the horizon and area maps.
The "Objects" tool palette makes this unnecessary.

Removed the "time skip" facility from the horizon map. This has been
superceded by the "real time" facility, and the "Time" tool palette.

Removed the "maximize application window" from the "Display" page of
the "Preferences" dialog. The program now automatically stores the
position and state of the map window between program runs.

Bugs fixed:

On an Area Map, the altitude and azimuth displayed in object
information dialogs was computed from RA/Dec positions to J2000
if the map was in "Astrometric" mode - this gave slightly incorrect
alt/az. We now precess the coordinates to the epoch of date before
computing altitude and azimuth.

On an Area Map, if the RA/Dec grid was switched off, the ecliptic
would be drawn as a solid line regardless of the line style selected
for it.

On an Area Map, selecting a view centred exactly on the south pole
an "auto" RA/Dec grid spacing resulted in a grid of RA lines drawn
much too close together.

On a printed map, dates prior to 1AD are now labelled "BC", rather than
the year being displayed as a negative number.

When setting the margins around the edge of the printed map, we now take
into account the "physical margins" of the device - ie the area around
the edge of the paper in which the printer is not physically capable of
printing. This means that the map will have the correct requested margin
sizes, measured from the edge of the paper.

In "Night Vision" mode on Windows 3.1, dialogs had a black background,
so we used red text. In Windows 95 dialogs now have a *red* background
and the red text when drawn on this was a little difficult to see! Text
is now drawn in the default black which is easily visible on the red
background.

The positions of Jupiter's satellites reported by the previous version
of the program were completely wrong. This turned out to be due to an
error in the Microsoft Visual C++ 4 compiler's optimizer. Disabling
optimization for the function which computes the satellite positions
now gives exact agreement with times of satellite phenomena listed in
the "Astronomical Almanac".

When executing the command to run the image viewer to display a
picture, we now convert the filename to a "short" (8+3) filename. If
the program is installed in a directory with a "long" filename
(eg "c:\Program Files\SkyMap" on Windows 95) and we attempt to view a
picture in this directory, a 16-bit picture viewer won't be able to
open the file.

When using "black and white" or "night vision" display modes we now
preserve the "normal" line style when drawing lines, rather than always
using a solid line. Previously, for example, if a dotted line was
selected for constellation boundary lines it would be drawn as a solid
line in black and white mode; it now remains a dotted line.

In the last release of the program we removed the restriction of only
being able to draw object tracks on astrometric maps, but the code which
computed positions along a track still assumed astrometric coordinates.
The result of this was that object tracks drawn for a long time in the
past or future were in the wrong position, since the track coordinates
were to J2000.0 whilst the rest of the map used the epoch of date. Now
fixed.

01-DEC-95 v3.0

New features added:

The single most important feature of this release is the switch from
16-bit to 32-bit compilers. Running as a 32-bit application is a
slight problem for users of Windows 3.1 (requiring the installation
of Win32s) but has the MAJOR benefit of making the program run 3-4x
faster! As the world switches to 32-bit Windows (Windows 95 and NT)
this will cease to be a problem.

Total rewrite of the printing functions. A wide range of new printing
options is now available, including setting a map title and entering
notes which will appear below the map. It is now possible to scale the
map so the specified field of view fits either the horizontal or the
vertical size of the paper, which means that (at last!) a whole sky
map can be printed in portrait orientation.

A new "Constellations" item on the Options/Setup menu allows the
labelling of constellations to be configured. Labels can either be the
full constellation name or the 3-letter IAU abbreviation (this is very
useful for whole-sky maps).

The "Daily Phenomena" dialog now has a "Copy" button which copies the
displayed information onto the Windows clipboard from where it can be
pasted as text into a word processor or other application.

Added a "Copy" button to all the object information dialogs to copy
the displayed information onto the clipboard.

Modified the information dialogs to explicitly state the epoch of
the displayed data. RA/Dec values can either be referred to epoch
J2000.0 or to the map's epoch of date and it was often not obvious
which it was for a particular object.

The "Search" dialogs now offer the choice of either drawing a map
centred on the object, or displaying the information dialog for the
object. This makes it possible to display information about any
object in SkyMap's databases without having to go through the
time-consuming process of drawing a new map first.

We now compute physical ephemeris data for Mars and display it as
both text and a diagram of the appearance of the planet on the
information dialog. The longitude and latitude of the centre of the
planet's disk, the position angle of the north pole and the illuminated
limb are all displayed, as well as a picture showing the actual phase,
the tilt of the polar axis, and the positions of the visible pole and
equator of the planet.

The information dialog for Jupiter now displays both physical ephemeris
data (the position angle of the north pole and central meridian
longitudes for both System I and System II), and also a diagram of the
positions of the Galilean satellites.

Physical ephemeris data for Saturn is now computed and displayed
in the planet information dialog. We display both numerical data and
a picture showing the correct appearance of the ring system. The
ring system data also allows us to correctly compute Saturn's
magnitude, whereas previously we only took account of the magnitude
of the planet itself, neglecting the contribution of the ring system.

Planet names can now be abbreviated to their first two letters.
This makes whole sky maps tidier.

Added an option to the comet dialog to configure the time period either
side of perihelion that comets are visible for. This was previously
fixed at one year, but caused an embarrassing problem when comet
Hale-Bopp was discovered nearly two years away from perihelion!

Displaying just the Messier objects on a Horizon Map is now very
much faster than before.

Moved all the object visibility buttons from the toolbar into a
separate "floating toolbox" which can be switched on and off with a
new item on the "View" menu.

Added a "Time" floating tool palette. This provides a quick and easy
method of changing the time and date of the map, allowing you to move
backwards and forwards any number of years, months, days, hours, minutes
or seconds with a single mouse click. A much requested enhancement!

When a map is first drawn using the Hubble GSC, we have to create an
index of all the chart boundaries in memory. This is quite a slow
process, taking about 30 seconds on a double speed CD-ROM drive. We
now cache this index to the local hard disk which means we can read it
instantly on subsequent runs of the program. This makes drawing maps
with the GSC a LOT faster.

Added an option to cache GSC data on the hard disk. This means that
when we read data from the GSC CD-ROM, we store a compressed form of it
on the hard disk, so subsequent maps of that area don't require access
to the CD-ROM. This makes map drawing a lot faster, and also allows GSC
data to be copied to a notebook or other computer without access to a
CD-ROM drive.

When drawing an Area Map by dragging a selection rectangle on another
area map, all the settings of the original map are used for the new map,
rather than the new map using the default settings. Defaults are
still used when drawing an area map from a horizon map.

On the Area Map, there is now an option to display stars as points of
differing brightness, rather than circles of different size. This
requires a video mode capable of displaying 256 or more colours
simultaneously.

On the Area Map's right-click popup menu, added a "recompute" option
to recalculate the map centred on the mouse position. This is not
the same as the "centre" option which simply attempts to scroll the
map so the clicked point is as near the centre as possible.

On the Horizon map, draw the Sun and Moon when they are up to a degree
below the horizon, so we can see them rise and set correctly. Previously
they were only drawn if the centre was above the horizon, so the rising
Sun/Moon wasn't shown until its centre was visible.

On the Horizon map, keys "N", "E", "S", "W" now activate the corresponding
direction buttons. Also, pressing the buttons resets the standard 90 degree
field of view as well as changing the azimuth.

On the Horizon map, key "Z" (Zenith) selects a view of the whole sky
centred on the zenith. This is equivalent to View/Zoom To/180 degrees.

The cursor keys now scroll the map.

When the map is initially drawn, and when it's repositioned using the
N,S,E,W,Z facilities the scrollbars are centred. This means that the
image will zoom in or out around the original centre of the view.

Added a dialog to give optional manual control over the spacing of the
Area Map RA/Dec grid.

The existing "Time Skip" feature allows the Horizon Map to automatically
advance by a specified interval. Added a new "manual step" feature to
move one step forwards or backwards manually.

Comets and asteroids labels on the map now include magnitude.

Planet symbols on the map can now optionally be displayed using the
same size symbol as a star of the same magnitude as the planet.

Bugs fixed:

On an Area Map on which either pole was nearly but not quite visible
the RA range calculations overflowed, sometimes resulting in stars to
one side of 0h RA not being plotted, or occasionally no stars at all
being displayed!

The Horizon map RA/Dec grid settings were not being saved when
"Save Defaults" was selected.

In the "Planet Visibility" and "Phenomena" dialogs, explicitly select
the "Arial" font rather than asking for a "generic" Swiss font. On
systems with many fonts installed the choice of font was often odd!

In the time skip options dialog, a 16-bit integer overflow occured
if a value greater than 9 was entered in the hours field.

On a black and white printed map. the ecliptic line was always drawn
as a solid line, rather than using the selected line style.

When multiple object tracks were visible on an Area Map, track lines
were drawn in the marker, rather than the line, colour.


01-JAN-95 v2.2

New features added:

When displaying comets and asteroids, a limiting magnitude can now be
specified. This is useful to prevent 17th magnitude comets being
shown if you only have a pair of binoculars!

The information dialogs now all explicitly use the "Arial" font rather
than simply asking for a "default" Swiss font. The previous method
led to a strange font being used to display information on some
machines with lots of fonts installed.

If a date a long way (more than 50 years by default) from the 2000AD
"epoch" is entered, and the program is in "low precision" calculation
mode, the program will display a warning that the resulting map could
have significant errors, and will offer to switch on high precision
calculation mode before calculating the map.

The line of the ecliptic can now be displayed.

A new panel on the status bar displays the limiting magnitude of the
stars on the map.

Maps can now be saved as a Windows bitmap format (.BMP) file. This is
a much-requested feature for saving a permanent record of a map. It's
also a great way of creating Windows "Wallpaper" files!

A new View/Copy menu item now copies the contents of the currently
active view onto the clipboard, from where it can be pasted into a
word processor or other application.

SkyMap can now display on an Area Map stars (and other objects) read
from the "Hubble Guide Star Catalog" (GSC) CD-ROM database. This set of
2 CD-ROMs, published by the Space Telescope Science Institute, contains
approximately 19 million objects covering the entire sky to below
magnitude 14. This facility is NOT available in the shareware version of
SkyMap, but is provided as a new program "SkyMap/GSC", details of which
are on the registration form.

Added two new buttons to the toolbar to respectively add and subtract
half a magnitude from the limiting magnitude of the map. This gives a
quick way of rapidly changing the number of stars displayed. These
operations have F4 and Shift+F4 as keyboard shortcuts.

Added an option to automatically scale star image sizes to the limiting
magnitude of the map. This, when combined with the above facility to
rapidly alter the map's limiting magnitude, assures that maps retain a
"realistic" appearance when the magnitude limit is altered.

The program now carries out better checks to decide quickly if an
object is visible on the area map. This has reduced the time taken to
compute an area map by 25-40%, depending on the circumstances.

We now use a much more efficient method of drawing the altitude/azimuth
grid on the Horizon map. This significantly speeds up map drawing for
slow machines when the map field of view is small.

Added "Tool Tips" to the Toolbar. These are short help messages which
pop up after the mouse has been over a button for a brief period,
describing the function of that button. This feature can be disabled
using a new option on the global preferences dialog.

The N,E,S,W buttons on the horizon map toolbar now remain "pressed in"
when the map is drawn for those directions. This makes it easy to see
at a glance which (if any) cardinal direction the map is facing.

A grid of right ascension and declination lines can now be displayed on
the horizon map.

A new option on the Area Map popup menu allows the user to draw Telrad®
finder circles centred on the point clicked on. The Telrad finder is a
very popular device, and this is a much requested feature.

The program now has user-maintainable databases of eyepiece and
telescope data in files "EYEPIECE.SKY" and "SCOPE.SKY" respectively.
An "Eyepiece" item on the "Tools" menu displays the database, allowing
the user to add, edit or delete entries, and to see the magnification
and field of view resulting from using any eyepiece on any telescope.
On the area map, the field of view can be displayed as a circle on the
map with a new "Eyepiece" option on the popup menu.

The map size calculations now take acount of the presence of the tool
and status windows. The effect of this is that a maximized map window
now never has scroll bars.

The time of rise, transit and set can now be displayed for all objects
on the map, not just planets.

We now cache rise, set and transit times of planets, so they only have
to be computed (a slow process) once, appearing instantly when
displayed subsequently.

The program can now display the tracks of an arbitrary number of moving
objects at the same time. Previously, only one object at a time could
have its track shown. Tracks are also now saved with files, which
didn't happen previously.

Object track settings are now stored as a part of the Area Map defaults.

The status bar now contains a panel which displays the angular
separation of the last two points to be clicked on with the left mouse
button.

A new area map can now be drawn from an existing one by dragging a
selection rectangle with the left mouse button. It was not previously
possible to draw a new area map from an existing one.

An area map can now be drawn from a horizon map by dragging a selection
rectangle with the left mouse button. This is a much more convenient
method than the current one of pressing the right button over a point
on the map because it allows the map size, as well as the centre, to be
specified.

Bugs fixed:

On all the information dialogs, fixed the formatting problems with
angles and times which occasionally resulted in displays such as
"2m 60s" instead of "3m 0s".

On the area map, deep sky objects drawn with the "general" circle were
being drawn at twice the correct size.

On the "Planetary Phenomena" dialog, display times correctly rounded to
the nearest minute, rather than just "chopping off" the seconds.

We no longer get spurious "Identify Star" menu items appearing on the
popup menu for stars whose position has been computed, but which are
fainter than the current limiting magnitude of the map.

In the map status dialog, the sign of the observer's longitude (ie E or
W) was being set from the sign of the latitude, not the longitude.

Very odd things happened under certain circumstances when an Area Map
was printed showing the Moon with the "dark limb visible" option turned
on. These included stars being printed as hollow rather than solid
circles, and stars being labelled with a Latin rather than Greek font.
I'm still not exactly sure of the cause of this, but changing the method
used to draw the Moon bitmap appears to have fixed it.

If the horizon map was precisely centred in the window (eg if it was full
screen with no scroll bars) and we attempted a zoom, the program crashed
with a "Floating Point Invalid" error due to attempting to evaluate 0/0.
We now check for this special case and act correctly.

A missing term involving the Moon's semidiameter meant that the time
of rise and set of the Moon was about 1 minute in error.

On the area map information dialog for planets, display negative
altitudes correctly.

The horizon map "high precision" flag setting and the Moon dark limb
visibility flag weren't being correctly saved when default settings
were saved.

When computing the times of rise and set, use the local date, not the
UT date. This was causing the program to occasionally display times
for the previous or following day when used in time zones other than
GMT.


01-JUL-94 v2.1

Times of rising, meridian transit, and setting can now be calculated for
the Sun, Moon and planets. This is displayed on the "local" page of the
planet information dialog, and can also be displayed in a tabular form for
all the planets from a new "Planetary Phenomena" item on the "Tools" menu.

Added a "Planet visibility" dialog giving a quick method of showing the
positions of all the visible planets.

Added the option to label planets with names, rather than symbols. A new
planet options dialog allows selection of options for planet display.

Added an option to display the dark limb of the Moon with a dotted line.
This is useful for eclipses and occultations.

Improved comet orbit calculation algorithm to avoid problems with
comets in near-parabolic orbits. This problem sometimes caused the
program to crash previously.

Changed from the RNGC to the SAC v6 deep sky object database (by kind
permission of the Saguaro Astronomy Club). Deep sky objects are now
displayed on the Area Map with their correct size and (for galaxies)
orientation. This is a major improvement in the program!

Added a "black on white" display mode option to the "Colour" sub-menu.
Selecting this option changes the map to all-black on a white background,
similar to a printed map. This is a very useful mode in which to do a
screen dump for pasting into a word processor or other application.

Added a "night vision" display mode option to the "Colour" sub-menu. When
selected, all displayed items change colour to red or black. This colour
combination is the best for preserving night vision.

Added the ability to display the tracks of moving planets, asteroids, and
comets on the astrometric area map. This is extremely useful, especially for
comets and asteroids. Also has educational value when used for such things
as displaying the retrograde loops of objects.

Added a catalogue of asteroids in the file "ASTEROID.SKY". This works in the
same way the existing comet catalogue does - ie, asteroids can be selected
for map display, and can be added to, edited, or deleted from the catalogue.

Added topocentric RA and declination to planet information dialogs.

Replaced "High Accuracy" option on the Area Map with the more meaningful
"Astrometric" option. When this is enabled, maps are drawn to epoch J2000;
when disabled, maps are drawn to the current epoch. It has much the same
effect as switching off the old "High Precision", but in a more quantifiable
manner.

Added "double click" processing to all listboxes as a shortcut.

Added file load/save facilities for maps.

The user can now set the map window title on both the Horizon and the Area
maps.

Added a "time skip" option to the Horizon Map, allowing it to automatically
update at specified time intervals.

Added a "Map Status" option to the "Help" menu, When invoked, this displays
a dialog showing information about the time, observation location, etc.

Created a separate "SKYIMAGE" application for displaying pictures. Having
pictures shown in a separate window greatly improves the user interface,
since both the image and map can be viewed simultaneously.

Added the facility to display the embedded comments in GIF files. These
often contain useful information about the image, especially in the case
of NASA/JPL images.

Added altitude and azimuth display to Area map information dialogs.

Added screen and printer font selection for all text drawn on maps.


27-DEC-93 v2.0

Major release. A total rewrite of the program to make it much faster and
to dramatically improve the user interface. Many new features added
including display of comets.


10-Sep-93 v1.33

Bug-fix release:

Images of RNGC objects couldn't be displayed automatically on a horizon
map, because I'd forgotten to add the line of code to do so! Fixed.


25-Aug-93 v1.32

Bug-fix release:

An error in the floating point emulation libraries of Microsoft's Visual C++
compiler, causing the "tan" function to return the wrong sign, was resulting
in the effects of refraction being applied in reverse on some machines
without a maths co-processor. Applied a "work around".

The colour of RNGC objects and their labels was defaulting to black on the
horizon map. This was difficult to see against the black map background!


04-Jul-94 v1.31

Minor bug fix release:

It wasn't possible to save a configuration in which the faintest stars were
drawn as a single pixel. Single pixel stars were replaced by 4-pixel stars
by over-zealous error checking code when the configuration was reloaded.

RNGC objects on the Area map were being incorrectly drawn and labelled using
the star, rather than the RNGC object colours.

An extra line connecting the two halves of the constellation "Serpens" was
being drawn on the constellation outlines, because the drawing code regarded
Serpens as a single constellation whose points were to be connected. Fixed
by treating the two halves of Serpens as two separate constellations as far
as the outline drawing code is concerned.


29-May-93 v1.3

New features:

The program can now display non-stellar objects. The database used is the
Revised New General Catalogue (RNGC).

Constellation boundaries can now be displayed.

The printing options have been greatly expanded. When a map is printed the
user can now select whether to print the entire map, or the current zoomed
view, and also whether to print in black and white or colour. For colour
maps a dialog allows the user to select the colour of each component of
the map.

All map features are now present on both the horizon and sky area maps
(eg star labels can now be displayed on the horizon map). The user interface
has been made more consistent between the map types.

The program now has an optional ToolBar at the top of the screen, which
provides short-cuts for the commands on the "View" menu.

The program now (finally!) has a complete on-line help system. This is
basically a copy of the manual.

Bug fixes:

I'd forgotten to apply the correction for diurnal parallax to planetary
positions on the Sky Area map. Consequently, the planets were being shown
in their geocentric, rather than topocentric positions, resulting in errors
of up to 2 degrees in the apparent position of the Moon. Fixed.

The size of the image of the Sun and Moon on the Sky Area map was being
incorrectly calculated, resulting in images that were about 50% too large
when the map was printed on a portrait orientation page. Fixed.


07-Mar-93 v1.2

New features:

Added a new "Sky Area" map type, centred on a right ascension and
declination. This is intended to be used to draw a detailed map of a
small region of the sky.

Added the ability to display photographic images in either GIF or BMP
format. Images can either be explicitly opened, or associated with specific
objects (currently planets) and automatically displayed.

Bugs fixed:

Single pixel stars were being printed on the printer in the screen colour,
which almost certainly mapped to white on the printer, resulting in them
not being printed. On a mono print, single pixel stars are now correctly
printed black.

When the right mouse button was pressed over a horizon map to display the
pop-up menu, then the *right*, rather than the *left* button pressed (ie,
a user input error!) an incorrect cursor position was stored. If the left
button was subsequently used to select an information dialog a wildly
inaccurate position or a GPF resulted. This is probably the cause of all
the "random number" errors previously reported. Thanks to Don Munro for
tracking down a reproducable case of this puzzling error! Fixed.

Removed the incorrect, uninitialized data displayed on the information dialogs
for the Sun and Moon. (Eg phase 0.000 for the Sun.)


05-Feb-93 v1.11

When the start of a constellation figure was off the edge of the map,
the first visible line of the constellation was being drawn incorrectly in
certain circumstances. Fixed.

The correction for refraction was being correctly calculated and correctly
displayed in the "About" box for a star, but not applied to the plotted
position of the stars on the map. This led to stars being plotted with
slightly too low an altitude (the maximum error being about half a degree
at the horizon). Fixed.

If the star position calculation was aborted by the user pressing the "Cancel"
button, the subsequent constellation figure setup calculation code displayed
an error message for each star it was unable to find. Pressing the "Cancel"
button now aborts the map calculation cleanly.


31-Jan-93 v1.1

Test release to BIX only for testing.

In the "Observer" dialog, the "Time Difference" edit field was only wide
enough to allow two digits to be entered, making the program not too
useful for anyone outside the GMT time zone. Fixed.

Version 1.0 of SkyMap simply plotted stars in their mean catalog position.
This version now rigorously calculates the apparent place for the time of
observation, correcting for proper motion, aberration, precession, nutation,
and refraction.

Added code to verify that dates are in the range 4000BC-8000AD (the
range over which the planetary position equations are valid.


24-Jan-93 v1.0

Release of SkyMap 1.0, with basic facilities for drawing horizon map and
plotting planetary and lunar positions.


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