New in 2008
Since it was first introduced 10 years ago in 1998, the 900GTO has been a solid, reliable performer both in the field and permanently mounted in an observatory. These are the only significant changes in this 2008 production run:Why a 900GTO?
Stability ... accuracy ... ease of setup ... friendly go-to control interface - these were the primary design goals of the 900GTO. Amateurs today demand a precise mount that will allow them to pursue all aspects of astronomy whether it be observing visually, CCD imaging or photographing with 35mm or 6x7 camera. Many of the finest imagers today have been using our GTO mounts as a solid platform for a wide variety of instruments. The largest of the current production mounts is our 1200GTO the next in line is the 900GTO and the most compact is the Mach1GTO. As I write this in early 2008, final preparations are underway for our new very large 3600GTO German Equatorial, also known as El Capitan. However, if your instrument of choice is a medium-sized refractor, Cassegrain, Ritchey-Chretien, Newtonian or astrograph, the 900GTO may be the ideal choice for you.
Since its introduction in 1998, the 900GTO has gained a reputation for both tracking and pointing accuracy, essential to casual visual observation as well as advanced imaging. Quite a few 900GTO and 1200GTO mounts can be found at major star parties throughout the country and the world. It is a favorite of many advanced photographers and imagers. Visit the Cool Sites and Gallery sections of our website to see photos of the mount in action and images taken while using the 900GTO.
These mounts are truly a marvel of engineering - maximum strength and rigidity with minimum weight. Our CNC lathes and mills carve out the excess material in both axes of the 900GTO German Equatorial 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 900 equatorial 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 and the reasonable weight of each component; the heaviest is only 25 lbs! Telescopes commonly used include Astro-Physics 155-180mm refractors, 10-11" Schmidt-Cassegrains, 10" Maksutov-Cassegrains and 10-12.5" Ritchey-Chretiens and other scopes of similar size and weight.
Gilles Cohen, of France, has been using his 900GTO for several years and has documented its impressive performance. He not only prepared a beautiful French page to show off the mount, but he also was inspired to prepare a second page in English for the rest of us. Gilles is a rising star imager who does his work from a major urban site with lots of light pollution and not always the best seeing, but has managed to take some excellent astrophotos - some of which are posted on his Gallery Page.
The 900GTO mount is built from the ground up to be a precision imaging platform while still being totally user friendly. Consider these advantages and features:
Versatility
R.A. worm wheel |
7.2" (18.3cm), 225 tooth aluminum |
Declination worm wheel |
6" (15.2cm), 225 tooth aluminum |
Worm gears |
Brass |
R.A. thrust surface |
7.0" (17.8cm)diameter |
Declination thrust surface |
6.0" (15.2cm) diameter |
R.A. shaft |
2.2" (5.6cm) diameter |
Declination shaft |
1.75" (4.4cm) diameter |
Latitude range |
20 to 68 degrees with or without the polar scope attached. |
Azimuth adjustment |
Approximately 15 degrees |
Setting circles |
Porter Slip Ring design, engraved |
Right ascension |
4 minute increments, pointer, engraved both Northern/Southern |
Declination |
1 degree increments, pointer |
Motors |
Zero-cogging servo motors |
Power consumption |
0.4 amps at the sidereal rate |
Power requirements |
12 VDC, range 11.5 to 16 |
Weight of equatorial head |
54 lbs (24.5 kg), Declination axis is 17 lbs. (7.7 kg) right ascension axis is 26.5 lbs.(12.0 kg), counterweight shaft with washer and knob is 10.5 lbs. (4.8 kg) |
Capacity |
Approximately 70 lbs. (31.8kg) scope and accessories (not including counterweights), depending on length. Will accommodate Astro-Physics and similar refractors up to 180mm f9, 12" Cassegrains, 12-14" Ritchey-Chretiens |
GTOCP3 Servo Motor Drive System
The servo drive system uses a high-quality Swiss DC servo motor controlled by a microprocessor to an accuracy of 0.05 arc-seconds per step. Tracking is very smooth, noticeably smoother than any stepper motor drive or inexpensive servo motor. The system can be accurately controlled over a speed range of 4800:1, which allows 0.25x sidereal for guiding to 1200x sidereal for 5 degree per second slewing. The circuit draws only 0.4 amps when tracking the stars, 2 amps with both motors slewing and requires only 12 volts to operate. The servo drive will satisfy the requirements of the sophisticated, advanced astrophotographer, yet is easy for the casual, visual observer to use.
The GTOCP3 Control Box contains all of the circuitry to drive the two servo motors and the logic required to navigate the sky. It can be easily removed from the mount, if required.
The GTO Keypad is a self-contained computer that serves as the communication center for the operation of your GTO mount. We have designed the interface and firmware to be as intuitive and easy to use as possible while filling it with terrific features to make your observing session productive and pleasurable.
All of the 900GTO electronics are now lead-free. Astro-Physics believes that we who love the night sky should also love and protect our good earth. Please refer to GTOCP3 Control Box and Keypad for Servo Drive for more detailed information.
Please note: Ray Gralak, the author of PulseGuide, is currently working on a new piece of software that will combine the Astro-Physics ASCOM driver, all the features of PulseGuide, plus additional features. The new software will also act as a hub for a number of other applications that can then all communicate with the mount through a single COM port. The new software will have a new name befitting its vastly increased capabilities, and will replace PulseGuide when it becomes available. In the mean time, here's the lowdown on the existing PulseGuide software:
PulseGuide is a stand-alone Windows (98, ME, 2000, NT4, XP only) utility that provides complete remote control of the Astro-Physics Mach1GTO, 400GTO, 600EGTO, 900GTO, 1200GTO and 3600GTO 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. With just a few exceptions, it supports the entire serial Astro-Physics command protocol allowing full control of your mount through your PC. This program is indispensable for remote control of your mount. More information on our website ....
PulseGuide was written by Ray Gralak of Sirius-Imaging. Please refer to his web site http://www.pulseguide.com for further developments and enhancements. The software will be provided on a CD-ROM with your 900GTO mount. Previous owners of any Astro-Physics mounts can download the software free-of-charge, courtesy of Ray. Many, many thanks to Ray for this powerful program.
PEMPro Software, Version 2The 900 Standard Pier Adapter (900SPA) was included with 900 mounts sold in the past. However, in 2005, we decided to offer several choices to meet a variety of needs. We ask that you add one of these options to your mount order. If you plan to have multiple pier installations, perhaps one permanent and another portable, you may wish to purchase an extra adapter to install on the the second pier. This will make your setup and switchover much quicker. Many customers have found this to be advantageous.
If you do not purchase one of our pier adapters described below, for instance, if you purchase the Monolith Pier from Particle Wave Technologies, you will need to purchase the Pier Adapter Knob Kit (part# 9KBKIT) in order to attach your mount to the Monolith.
Complete descriptions and photos are available at the links below.
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People often ask us what the 900GTO's dimensions are. The answer is: It depends. Different latitude settings can drastically affect the shape and dimensions of the mount. To answer this question we have prepared the following PDF document: 900GTO Dimension Sheet and this Excel spreadsheet Latitude Dimension Calculator. Please note: both this sheet and the calculator show the latest version of the 900GTO with the new improved Polar Fork. To see an example of an older polar fork style, go to the History section of our website. As the dimension sheet points out, all horizontal dimensions are the same for ALL versions of the 900 mount. If you have a different looking polar fork from the one pictured on the 900GTO Dimension Sheet, simply subtract 7/8" from the vertical dimensions. |
Support
All Astro-Physics mounts are supported by a dedicated staff who will assist with any issues that may arise. You can talk to a real person in a timely manner. Astro-Physics staff also participate the ap-gto user groups in the Yahoogroups forum. The user group is comprised of GTO owners who are willing to share their wealth of experience using their mounts as well as imaging strategies and other concerns of advanced amateurs.
Price and Delivery Information
With rare exception, the 900GTO is
not available on the shelf for immediate purchase. We typically maintain notification
lists so that we can notify prospective customers when the mount is available
to order. Please refer to our availability page for more information
on our notification lists. If you are not already on the notification list for
the 900GTO, you can sign up on our online
notification form. An automatic confirmation e-mail will be sent to you
for your records. Refer to Notification
Update periodically to find out the status our mount and telescope production
runs - what we are making throughout the year.
900GTO | $8,450.00 |
Astro-Physics, Inc.
11250 Forest Hills Road, Machesney Park, IL 61115, U.S.A.
Phone: 815-282-1513 Fax: 815-282-9847