ASTRO-PHYSICS German Equatorial 1200GTO, Manual, Page: 6 / 38

INTRODUCTION
The 1200 German equatorial was designed to meet the needs of the advanced observer who requires a mount with
maximum strength and rigidity and minimum weight. The excess material in both axes has been carved out while retaining a
heavily ribbed structure for internal strength and rigidity. A unique dovetail was machined into the mating surfaces of the R.A.
and Dec axes. This feature allows quick and easy assembly in the field without any tools.
The DC servo motor drive with GTO computer system, the keypad with its digital display screen, and the included
PulseGuide™ and PEMProAP™ software all combine to offer extraordinary sophistication for today’s observer. Whether you
enjoy visual astronomy exclusively or plan an aggressive astrophotography or CCD imaging program, this mount will allow
you to maximize your night out under the stars.
The advanced keypad features allow you to slew automatically to objects in a wide range of databases as well as any
R.A./Dec coordinate. A large selection of common names for stars and other objects makes your selection a snap. The rapid
slew rate of 5 degrees per second (1200x) allows you to locate objects very quickly and accurately. You will be very pleased
with the intuitive operation of this keypad. There are no complicated sequences of keystrokes to remember. It is so easy to
use that even if you don’t use it for a few months, you will feel at home with the keypad very quickly.
PulseGuide™ is a stand-alone Windows (98, ME, 2000, NT4, XP, Vista) utility that provides complete remote control of all
Astro-Physics GTO mounts. It derives its name from its most distinctive feature, pulse guiding, which can improve unguided
tracking. Specifically, it can help correct tracking errors caused by polar misalignment and atmospheric refraction. You can
also train PulseGuide™ to track objects moving relative to the stars, such as asteroids, comets, and the moon. In addition to
pulse guiding, PulseGuide™ also has many useful utility features. PulseGuide™ was written by Ray Gralak of Sirius-
Imaging. Please refer to his website
http://www.pulseguide.com for further developments and enhancements.
PEMPro™ (Periodic Error Management Professional) is a Windows software application that makes it easy to characterize
and reduce periodic error. PEMPro™ will analyze the performance of any mount that is equipped with a CCD camera and
compatible camera control software. PEMPro™ gives you powerful tools to program your mount's periodic error correction
firmware to achieve the best possible performance for your mount. PEMPro™ dramatically improves guided and unguided
imaging resulting in better images and fewer lost exposures. PEMProAP™ is a special edition that can only be used with
Astro-Physics mounts. While the native periodic error of your 1200GTO will be 5 arc seconds or less, you can reduce it even
further to maximize performance without auto-guiding. PEMProAP™ is included with all 1200GTO mounts that will ship in
2007. As an added bonus, starting in 2007, all 1200GTO mounts will come pre-loaded with the custom fitted PEMPro
corrections from our extensive individual testing that is performed on each and every mount.
The 1200 is equally at home in a permanent observatory or as a portable mounting for remote star parties thanks to the ease
with which the two axes come apart. This is the perfect mount for a large refractor, Newtonian, Cassegrain or astrograph.
In order to maximize your pleasure on your first night out, we
recommend that you familiarize yourself with the assembly
and basic operation of the mount indoors. The temperature
will be comfortable, the mosquitoes at bay, and you'll have
enough light to see the illustrations and read the manual.
Please take particular note of
counterbalancing, use of the
clutches and operation of the keypad controller.
Why Polar Alignment is Important
Polar alignment compensates for the Earth’s rotation.
If you were to take a long exposure photograph with Polaris
(often called the north star) in the center of the field, you
would discover that all stars seem to revolve around Polaris.
This effect is due to the rotation of the earth on its axis.
Motor-driven equatorial mounts were designed to
compensate for the earth's rotation by moving the telescope
at the same rate and opposite to the earth's rotation. When
the polar axis of the telescope is pointed at the celestial pole
(polar aligned) as shown in the diagram at right, the mount
will follow (track) the motions of the sun, moon, planets and
stars. As a result, the object that you are observing will
appear motionless as you observe through the eyepiece or
take astrophotos.
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