Frozen Fish 2: PC/frozenfish_august_1995.bin/bbs/d09xx/d0932.lha/DynamicSkies/Docs/Presentation.doc

Text File | 1993-12-20 | 10KB | 188 lines

' Dynamic Skies '               Presentation.doc

' Author : Patrick DEBAUMARCHE


QUICK VIEW OF THE ASTRONOMY PROGRAM : 'DYNAMIC SKIES'
-----------------------------------------------------

    'Dynamic Skies' is a big toolbox for astronomy and has for ultimate goal
to answer with speed at any question that may arise on celestials objects. For
example, suppose you have an urge to observe Jupiter tonight from your window.
You may consult rise/set times of Jupiter, ask when it crosses south-west
( supposing your window faces south-west ), and with just a mouse click have
a glance at the simulated sky at this time. You may even animate Jupiter's
path across the sky with a time-step animation. Of course, if you're a real
star gazer, don't forget your binoculars or telescope for the real thing.
The only thing this program won't predict is the weather !

    Dynamic Skies is versatile, and whatever star, planet or object you're
after, you'll have easy access to both numerical and graphical data. It also
features a LOT of options ( see COMPOSITION chapter ). One thing possible, for
example, is to compute an animation showing star proper mouvements in a
given constellation; another is a month calendar formated to your choice of
data ( as moon phase or coordinates ).

    If you're already an amateur of astronomy, this program is for you, and
it's very easy of access and features known stuff of the astronomical world.
People not initiated may just be frustrated. My only counsel for these people
is to procure themselves with a small beginners guide for astronomy. Many of
these are cheap and well documented.


WHY YOU MAY USE DYNAMIC SKIES ?
-------------------------------

    First of all, the Amiga market is far from being flooded by astronomy
programs, even farther if you consider really good programs and cheap.
Besides that, or you just get another boring planetarium or you have to
invest in a very expensive and slow program. When you have already
scratched your bank account to the last cent for a good telescope, how can
you afford a 130$ software without counting the add-ons ?

    So, the diffusion of my registered version will be assumed by myself,
with free updates and free star or object libraries releases. You won't
go bankrupt with me.

    And talking of quality, I fought ( many times with my good friend the
GURU ) and spent DAYS just for user-friendliness and power. The result is a
simple utilisation, a very precise computing for arcsecond maniacs, and very
important, a fast computing, because I hate waiting minutes for a screen to
build up with a star map. I tried to stick to these rules, learning both
Rom Kernel manuals and assembly language for that. By the way, I thank
Intuition.library for being so ... intuitive.
    'Dynamic' was inserted in the title, not only speaking of the simulator
side of this program, but also in mind that the user has a right for a
dynamic interface. Keyboard times get to the end, whatever the PC maniacs may
say, especially when they cling to these prehistoric Operating Systems, or
when the newer ones ( Windows NT for example ) just gulp 8 Meg of RAM and
20 Meg of HardDisk and disdain processors prior to the 486. Just consider
the power of the Amiga OS 3.0 with it's tiny half meg of ROM. In short, I
hate PCs because such dumb computers rule now the world, thanks to efficient
advertising and economic inertia.
    Whatever, what I promise for 'Dynamic Skies', and I hope I haven't failed
( YOU'll tell me ), is user-friendliness, speed and power, even with slow
and memory short Amigas. What's more, you won't have to digest ENORMOUS docs.

    My last point ( sorry for being verbose, I just get hot talking of PCs ),
is that you have the honor ( applause ! ) of testing 'Dynamic skies' right
now with this Public Domain release. And when you're satisfied, you may
register for the complete program. That's business, and no bad surprises.
Just read the following chapter and let your Amiga vibrates for you ( even
at 7 MHz ! ).


BE SMART : REGISTER !
---------------------

    I can't garantee perfect results, but as the saying goes, I've done my
best. It's you, user, who will tell me what needs improvement; Future versions
( already planified ) will take account of your desires too. So be prepare
to register ( two LONG years of development merit a reward ! ). The price
is ridiculous ( 45 US$ ) for a program of this type ( although of course you
won't believe me if I tell I have no interest in gains  ; but my true desire
is to promote good quality programs for the Amiga ), but you'll get free
updates ( 3 to come ) plus free libraries release plus other programs
very interesting ( like importing stars and objects libraries from other
programs or computers, like PCs ( Argh!) ). But just have a glance at the
'Register.doc' file in the 'docs' drawer for complete information.
    Don't hesitate; even on an old Amiga 500, Dynamic Skies may make old
that PC486 of a friend who just cackles everytime on your 'games machine'
( what an horrible concept for theses serious users, who have of course never
fed their so serious pet with a game software ).


COMPOSITION
-----------

    'Dynamic Skies' is composed of 4 modules in the same program :
Numerical Ephemeris, Planetarium, local Sky and Events. Every one of them
shares the same options, the same libraries, and the same procedures of
sorting, computing and graphic interface. You can hop along the modules
intuitively and immediately. The search of planets, stars and objects is
wide, accepting many known formats as usual names, HD, SAO , M, NGC, ...

    NUMERICAL EPHEMERIS lets you get numerical data on the object of your
choice. With 4 specific commands, you may print a complete ephemeris, a
month calendar, distances, and rise/set/meridian times.

    PLANETARIUM displays a celestial sphere map at a given date. You may
scroll, zoom, watch numerical options act like equinox precession or
parallaxe. You may affect stars aspect shape ( real, specter, map ), add
figures like grids, ecliptic, constellation limits and patterns or names
formatted to your choice. Magnitude limits can be set. Right mouse button
clicking brings info on pointed object while left mouse button clicking
moves the map at pointed location, with manual zoom possible while moving
the mouse after the click. Animations may be time-stepped or mouvement-
stepped ( mouvement programming ). Every object ( star, planets, deep sky )
is user defined. You may simulate binoculars or telescope, just by giving
characteristics ( like lens diameter, focal lenght, ... ). Maps may be
inverted on both axis for telescope's sake. You may directly measure angular
distances with the mouse at given points.

    LOCAL SKY replics PLANETARIUM exactly, with the difference that the maps
are rotated to appear exactly from your location on earth, in an Azimutal-
Height coordinate system ( Example : Azimut 180░ (North) and 45░ height (mid-
zenith) ). PLANETARIUM uses the Right Ascension/Declinaison coordinate system
based from the Earth orbit.

    EVENTS lets you get dates of peculiar celestials events, like lunar or
solar eclips, planetary transits, elongations, occultations, oppositions and
more.


Some technical data ... :

    Screen size adjusts itself to your resolution type ( NTSC or PAL ),
although you may alter that if you want. For more resolution, you can
also interlace the screen and while in maps mode ( PLANETARIUM and LOCAL SKY )
you may activate a full screen mode for maximal surface.
    Dynamic Skies configures itself also to a language of your choice ( French
or English for the moment ) ; this feature is internal to the program, and
so doesn't use the locale.library.
    Map projections of the celestial sphere are low in distorsion, wherever
you look, whatever the field, thanks to a little secret algorhythm of my own,
that I won't reveal for anything in this world. I have not used these dumb
and prehistoric projections like Mercator or Horizon...
    Plotting and computing routines were totally written in pure assembly
code for speed purposes. A mathematical coprocessor is not needed, not even
recommanded, for speed is there already. No extra cost, you see, not like
many astronomical programs.
    System programming was done in the glorious but so heavy C language, but
the program structure itself was written in the GFA-Basic language, a powerful
friend if you put out the compilator bugs. Two years of intense labors were
necessary to put in action this first version. 3 more at least should follow,
much faster, for many things still lack. See details in 'Register.doc'.
the computing principle of Dynamic Skies is speed. To gain that, I had to
give off to a well known physical rule : for more speed, you need more power
( Gate delay/Current intensity for electronic devices ). So power was taken
to the last speck in this program by using huge amounts of memory to optimize
data access. But you still manage with 1 Meg of RAM if your star library
doesn't exceed 10000 stars. Anyway, with 2 megs ( like my 1200 ), you have
a lot to load before your computer gives up !

About the planetary theory :

    I used the famous VSOP from the Bureau des Longitudes of Paris in a very
precise version ( down to 1 '' !, but without Pluto ), thanks to an
astronomer named P.Bretagon of this same Bureau. Only registered users will
have access to this theory, a simplified version being in action for this
public domain release ( One more reason for you to register ! ).


TO START :
----------

    Read 'Install.doc' for more details.

    If you want something really fun to start with, try this :
    To animate stars by their proper movement ( ever seen The Big Dipper
    mutating ?, it's fascinating... ), you need the Cat2000_mag4 library, as
    only this one includes proper movement data ( mu(alpha) & mu(delta) ).
    Choose a time increment rather heavy, like 10 centuries. Discard all
    numerical options like precession or nutation but just leave 'proper
    movement' activated. Leave also 'Follow target' on to let Dynamic Skies
    stay centered on your constellation. Remove planets and objects as they
    are unnecessary. Now you can manually 'advance' the time or better
    compute an animation for ease of view. Try 50 images with remanence on
    to watch the stars path.