The NexStar computer hand control has a built-in database of more
than 45,000 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, 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 via a personal computer. 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."
You have to know where you are in order to find your destination. That
is what aligning a computerized telescope is all about. The software for the telescope
needs to know the exact orientation of the telescope in relation to the night sky
in order to find the tens of thousands of celestial objects that are programmed
into the hand control.
Other methods for aligning a computerized telescope require the user
to confirm what star the telescope is pointing at in order to align. If you're a
newcomer to astronomy - one who in unfamiliar with the sky and isn't sure which
star really is Arcturus or Sirius - how can you confirm that information?
The best you can do is guess. SkyAlign is the only alignment method where
you truly do not have to know the night sky - and it's only available from Celestron.
The operation of the NexStar with SkyAlign is simplicity itself. Once
you mount the scope on its tripod in the altazimuth mode, turn on the power. 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 the last site you observed from). 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. There is no need to first
point the telescope north or to level the optical tube as in other alignment methods.
The initial position of the telescope is irrelevant. This makes for a fast and very
easy method for aligning the telescope.
The NexStar SkyAlign computer system automatically determines
which objects you chose 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. The display tells you
which three objects you aligned on 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.
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.
Several different alignment methods are built into the NexStar computer
in addition to SkyAlign, allowing you to choose a level of computer accuracy
in automatically finding objects with which you are comfortable. Both the Auto Two-Star
"quick align" procedure and two accurate three star alignment methods (one computer-guided)
are easily accomplished in only a few short minutes. You can be observing in less
than 10 minutes after you first take the scope outdoors, including telescope set-up
time.
For example, if you're 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 scope 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, the NexStar computer hand control is GPS-compatible (using
an optional inexpensive CN16 GPS module) for full GPS (Global Positioning System)
satellite accuracy. Adding GPS to the computer is something no competitive scope
can do. Once the scope is approximately polar aligned, the 16-channel CN16 GPS system
uses signals from government satellites to calculate the scope's location on earth
with an accuracy measured in meters. The system also calculates the current time
based on the split second accuracy of the GPS time signals. After the CN16 quickly
completes these calculations and enters the information into the computer control
for you automatically, the computer then orients the scope with the sky, slews to
a pair of guide stars, asks you to confirm that the stars are in the center of the
field (and center them if they're not precisely aligned), and then starts finding
and tracking over 45,000 objects for you at your command. With the NexStar go-to
mount and the CN16, orienting the scope in time and space on earth and aligning
the scope on the sky becomes almost as easy a task as simply turning the scope on.
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.
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