The NexStar computer hand control has a built-in database of more
than 40,000 stars, deep space objects, and solar system objects it can locate for
you. The computer's memory contains the following objects:

• the entire RNGC (Revised New General Catalog) of 7840 nebulas, galaxies, and star
  clusters

• the IC (Index Catalog) of 5386 nebulas, galaxies, and star clusters
• the Messier Catalog of the 110 best known deep sky objects
• the Caldwell Catalog of 109 fascinating objects that Messier missed
• 20 famous asterisms
• the Abell Catalog of 2712 galaxy clusters
• 25 selected CCD imaging objects

• 29,500 selected SAO stars, including variable stars and multiple star systems.

    Also included are the eight major planets out to Pluto, as well as
the Moon, for a total database more than 45,000 stars and objects. It's enough fascinating
objects to keep you busy observing for the rest of your life.

    You can also store and edit the right ascension and declination of
up to 400 objects of your own choosing, such as the comet and asteroid coordinates
published monthly in Astronomy and Sky & Telescope magazines. The
computer control can quickly find any of those objects at your command, and track
them with high accuracy for visual observing or casual astrophotography.

    A review in Sky & Telescope magazine commented, "To quantify
the Go To pointing accuracy, I spent several nights slewing to 50 objects selected
from the NexStar's database. About one-third of them ended up dead center in the
field, another third landed within ½° of the center, and the remaining third were
within 1° of the center."

    All of the database and scope operation information is displayed on
a double line, 16-character, red-illuminated liquid crystal display on the hand
control. This display leads you through the steps necessary to line up the scope
on the sky, locate objects, control scope functions like the brightness of the hand
control display, and much more. It shows you basic information about the object
being viewed (such as the object's name, catalog designation, type, magnitude, and
so forth). In addition to this basic information, there is enhanced information
on over 200 of the most note-worthy objects. When it's not displaying menus or object
information, the display also shows you the constantly updated right ascension and
declination coordinates at which the scope is aimed.

    The Sky & Telescope review said, "After using several NexStar-equipped
telescopes in recent years, I can attest to the quality of the software and hardware
for Celestron's Go To system. The package is reliable and offers quick access to
an excellent array of databases. I especially like Celestron's Tour mode, which
steps a user through an eclectic choice of deep-sky objects, quirky asterisms, and
fine double stars, the latter being a class of objects great for urban observing
that many Go To systems ignore. Using NexStar scopes, I've been introduced to many
fine double stars."

    There are 19 fiber optic backlit LED buttons that glow a soft red in
the dark to make it easy for you to control the computer without affecting your
dark-adapted vision. An RS-232 communication port on the hand control allows you
to operate the telescope remotely via a personal computer, using the supplied RS-232
cable and CD-ROM that contains Celestron's NexRemote control software program.

    NexRemote provides an on-screen image of the computer hand control
with full control of all the hand control functions from your computer keyboard.
In addition to emulating the NexStar hand control, NexRemote adds powerful new features
that let you keep your eyes on the stars instead of the hand control. It provides
talking computer speech support using your computer's built-in speaker; lets you
control the objects you want to see and the order in which you see them; lets you
create and save custom sky tours; lets you take wireless control of the telescope
with optional gamepad support; lets you connect your personal GPS device to the
NexRemote; downloads NexRemote updates online to use the latest features; lets you
download software upgrades to your NexStar computer at no charge from Celestron's
website via the Internet; lets you use third-party planetarium programs to control
the scope; and more.

    The Sky & Telescope review said, "The author tried Windows and
Mac programs, including Desktop Universe, ECU, MegaStar, SkyMap Pro, Starry Night,
and TheSky, and all controlled the mount without any problems." The telescope
comes with a CD-ROM of TheSky Level 1 planetarium and star charting software. This
Windows-based program will let explore the Universe on your PC and print out custom
star charts of the sky to help you find faint objects that are not in the scope
computer's database.

    A high precision pointing subroutine ("precise go-to") in the computer
lets you point accurately at objects that you want to photograph that are too dim
to be seen though the scope. Built-in programmable permanent periodic error correction
allows sharper astrophotographic images, with fewer guiding corrections needed during
long exposure photos through scopes with enough aperture to make such imaging practicable.
Built-in adjustable backlash compensation permits precise corrections during astrophotography
and when observing visually at high powers.

    The operation of the NexStar with SkyAlign is simplicity itself. You
don't have to level the scope or point it north with SkyAlign, or even know
Polaris from the Pleiades. After turning on the scope, enter the date and time and
your location. The scope's computer will remember up to ten different observing
sites for you to choose from, and will automatically default to your last observing
site (very helpful if you invariably observe from one location, such as your back
yard). Then, simply point the scope at any three bright stars, or at two bright
stars and a planet or the Moon (you don't even have to know which stars and planet
you're looking at, and you don't have to know and locate specific stars as you do
with other alignment programs). Using the scope's hand control, center the stars
in the finderscope crosshairs.

    The NexStar SkyAlign computer system automatically determines
which objects were chosen and generates an internal map of the sky that it uses
to guide its automatic moves to any star or object you select for the rest of the
night. It does it by calculating the angles and distances between the objects you've
chosen and compares them to the known separations between objects. Using this method,
the telescope determines what objects were chosen. The display tells you which three
objects you aligned to for confirmation.

    Only two of the alignment objects will actually be used for calculating
the model of the sky that the computer uses for locating objects. The third object
simply provides a positive identification of the other two. Therefore, at least
two of the three alignment objects should be spaced at least 60 degrees apart in
the sky if possible, and the third object should not fall in a straight line between
the first two alignment stars.

    Since the brightest stars appear first as the sky darkens at dusk,
the SkyAlign system is exceptionally easy to set up and use as night comes
on. You don't have to guess which stars are brightest, as only the brightest will
be visible in the early evening. The same holds true for observers from a light-polluted
suburban site, where only the brightest stars are visible to the unaided eye.

    Several additional alignment methods are built into the NexStar computer
- auto two-star alignment, manual two-star alignment, solar system alignment for
daytime observing, and a one-star manual alignment - allowing you to choose a level
of computer accuracy in automatically finding objects with which you are comfortable.
If you're more familiar with the sky, you can use the new Auto Two-Star Align method.
Enter the date, time, and the latitude and longitude of your observing location
into the hand control. If you don't know your latitude and longitude or can't determine
them from the grid lines on your state's road map, you can use the coordinates of
the nearest city from the list of hundreds in the instruction manual. The scope
will keep up to ten observing locations stored in its memory (backyard, vacation
home, favorite dark sky site, etc.), so you only have to enter the latitude and
longitude once.

    Next, align the scope manually on a single bright star from a list
of 40 in its memory. The NexStar will then automatically choose and slew to a second
alignment star. Check to be sure the second star is centered in the telescope eyepiece
and that's it. You've aligned the scope on the sky, ready for a night's go-to observing.

    In addition to moving the scope to any of the 45,000 objects in its
memory and tracking the object while you observe, the computer is loaded with useful
features. It has user-defined slew limits, which prevent the scope from moving to
objects below any horizon that you define. That makes it ideal for observing locations
that have the normal horizon view blocked by houses or trees. The computer has a
hibernate mode that lets you power down the scope without losing your astronomical
alignment. This feature allows you to find planets in the daytime after aligning
the scope the night before. The computer has a wedge align program that helps aligns
the scope on the celestial pole when you're using a tripod and wedge for long exposure
astrophotography.

    Once the scope has aligned itself with the sky, it takes only a few
keystrokes on the computer hand control to have the scope move automatically to
your night's first observing target and start tracking it so you can observe at
your leisure. You can find hundreds of fascinating deep space objects your first
night out, even if you have never used a telescope before. No matter what level
of experience you start from, your NexStar SkyAlign scope will unfold all
the wonders of the Universe for you, your family, and your friends.

    If you're using an optional equatorial wedge to polar align the scope
for long exposure astrophotography, two polar alignment programs in the scope's
computer (one for the Northern hemisphere and one for the Southern hemisphere) make
quick work of accurate alignment on the appropriate celestial pole. SkyAlign
does not work in the equatorial mode.

    You can click on the link below to download a brief RealPlayer movie
showing how quick and easy it is to line up your scope on the sky with SkyAlign.
There is also a link to download RealPlayer for free if your PC does not already
have the program.