Why a 1600GTO?
Thirty plus years of mount design and building expertise plus actually using the equipment has been employed to engineer and build our new 1600GTO mount into the most robust, high-precision mount in its class. We have enhanced its design and utility by incorporating additional optional features like absolute encoders, sophisticated control systems and a new precision polar scope to exceed the needs of even the most demanding astro-imager or visual enthusiast.
The 1600GTO mount is built from the ground up to be a precision imaging platform while still remaining totally user-friendly. Consider these advantages and features:
Improved Features Compared to the 1200GTO, its Predecessor
Although we believe that the 1200GTO will continue to provide years of excellent performance, we felt that the time had come to improve the ease of use and add new features to take it into the future. We listened to your suggestions and added a few of our own. Some of them make the mount easier to set up for portable use, others set the standard for remote imaging. The modular design allows you to easily upgrade your mount if you build an observatory for near (backyard) or remote (halfway across the world) imaging.
We also felt that we needed to increase the size differences between the Mach1GTO, 900GTO and the 1200GTO, which were too close together and overlapping. Since the "new 1200" has greater capacity than the original 1200, we felt that it should have another name and selected 1600GTO "Sweet 16". Nevertheless, it maintains the heart of the 1200. Here are some changes that you may find useful:
Extremely solid, rugged, high payload mount, yet the equatorial head comes apart into two components for hassle-free field setup.
Operate with 12V battery.
You can take it to the darkest skies and power it with a commonly available 12V battery. In the observatory, we suggest a minimum 5 amp filtered, regulated power supply like our 13.8-volt, 5-amp Power Supply (PS13V5A). For a heavy payload in cold conditions, we offer a 15-volt, 12-amp power supply (PS15V12AC).
Allow manual operation if power is not available. One of the truly unique features of the 1600GTO is the ability to use the clutches to help you balance your setup, then you can bolt the R.A. and Dec. axes in place so that they do not move for clutchless operation.
|The 1200GTO’s ability to continue tracking when past the meridian is an absolute winner for me. It avoids meridian flips (=imaging time) and reduces the need for expensive rotators. Jan Rek.|
|. . . I love the ability to place the OTA on the "wrong side" of the mount when starting an imaging session ("premature meridian flip") and which I have used extensively. This feature is pure INGENUITY! Anthony Ayiomamitis.|
|Construction||All CNC machined aluminum bar stock, stainless steel, brass; stainless steel fasteners|
|Finishing and Assembly||Every part is hand-finished and inspected. All assembly is done by hand, by highly skilled mount assembly staff.|
|Worm wheel - R.A. & Dec.||10.3" (262 mm), 225 tooth aluminum|
|Worm gear - R.A. & Dec.||1.22" (31 mm) diameter brass|
|Axis shaft - R.A. & Dec.||3.74" (95 mm) diameter|
|Shaft axis bearings - R.A. & Dec.||5.71" (145 mm) diameter|
|Latitude range||0 to 78 degrees|
|Azimuth adjustment||Approximately 13 degrees (+/- 6.5 degrees from center)|
|Counterweight shaft||1.875" (47.6 mm) diameter x 19.5" (495 mm) long [18.5" (470 mm) useable length], incl. large machined safety stop knob. Optional 9" (229 mm) shaft extension available.|
|Weight of mount||
Total: 114.0 lb. (51.8 kg)
|Capacity||Approximately 220 lb. (100
kg) scope and accessories (not including counterweights), depending on
length. Recommended for refractors up to 250 mm, 18-20" Cassegrains, Ritchey-Chretiens
These are only guidelines. Some telescopes are very long for their weight or heavy for their size and will require a larger mount. Remember also that imaging requirements are more rigid than visual observation.
|Instrument mounting interface||Refer to list of suitable mounting plates below|
|Pier adapter base diameter||9.775" (248.3 mm) Base. The base is an integral part of the mount and azimuth adjuster.|
GTO Servo Drive System
The drive system uses a high-quality, heavy-duty 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 manual guiding to 1200x sidereal for 5 degree per second slewing. The circuit draws approximately 0.5 amps when tracking the stars, 2.5 amps with both motors slewing and requires only 12 volts to operate. The servo drive will satisfy the requirements of the sophisticated, advanced astroimager, yet is easy for the casual, visual observer to use.
Gear Accuracy and PE Performance
The heart of this mount is a precision gearbox using custom high-quality fine-pitch gears, coupled to a highly accurate worm and worm wheel. These parts are manufactured and assembled at our facility and individually tested to meet or exceed our periodic error specification of 5 arc seconds (+/- 2.5 arc sec.) before introducing any periodic error correction. The PE is smoothly variant with extremely low ripple or moment to moment error. In contrast, mounts that use integral gearboxes have very small spur gears with tiny teeth and too few of them. This generally causes ripples in the tracking rate which are difficult to guide out.
Each mount is rigorously tested on our specialized periodic error tester. Only mounts that provide an accuracy of 5 arc seconds or better will pass this inspection. If the mount exhibits greater error, the substandard part is identified, replaced and the mount is retested.
Pre-loaded PEMPro Curve
As mentioned above, the spec of 5 arc seconds (+/- 2.5 arc sec.) is the maximum native mechanical error inherent in the mount's RA axis WITHOUT any software correction. In order optimize performance even further, we use a special version of Ray Gralak's PEMPro (described below) developed specifically for our test equipment. We generate a unique PE curve for each mount that we program into each GTOCP3 Control Box. Simply use the Keypad or your Astro-Physics software (ASCOM V2 driver, PulseGuide or APCC) to turn the PE Correction "on" and you will see results significantly better than our published 5 arc second spec without additional PEMPro runs! However, you may use PEMPro to further refine your PE, if you chose to do so.
GTOCP3 Control Box
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 1600GTO uses the same GTOCP3 Control Box as the 1100GTO and Mach1GTO (the control box is black-anodized for the latter mount). In fact, the control boxes for all three mounts are interchangeable with one another in an emergency. Extensive information regarding the GTOCP3 can be found here.
The Keypad is a self-contained computer that allows you to control all essential telescope functions and includes an extensive database of objects. 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. Click here for detailed information regarding features and functions of the Keypad.
Optimized for Astronomy
Astro-Physics mounts and the Astro-Physics GTO Servo Control System are designed from the outset as tools for celestial observing and imaging. These mounts do not have any military or defense applications. Applications like missile, airplane, or very low earth orbit satellite tracking require faster tracking rates and more rapid changes to those tracking rates than our mounts allow. Note that the ISS is generally within the mount’s tracking rate capabilities for casual observation.
GTO Servo Drive System Specifications
|Electronic components||Rated for industrial and automotive applications|
|Motors||High-torque, zero-cogging Swiss DC servo motors, enclosed in machined aluminum housing|
|Motor encoder||2000 tic quadrature yielding an effective resolution of 0.050 arcseconds per tic|
|Motor reduction gear train||57.6:1 gear reduction through a custom built set of large diameter, fine-toothed, precision, spur gears for vastly superior performance|
|Servo Motor Control Box||GTOCP3 Control Box, removeable|
|Hand-held computer||GTO Keypad to control all mount functions. Includes extensive databases and tour features in a simple, intuitive interface. Firmware updates via the internet|
|Power consumption||~ 0.3 to 0.6 amps at 13.8 volts - tracking
~ 1.3 to 2.5 amps at 13.8 volts - both motors slewing at 1200x
|Power requirements||Nominal 12 volt DC supply at minimum of 5 amps continuous|
5 arc seconds peak-to-peak (+/- 2.5 arc seconds) or less in one worm cycle (6.4 minutes); native, prior to any error correction
|Maximum slew speed||5 degrees / second|
Absolute Encoders (optional)
The 1600GTO mount has been designed and engineered to accomodate the use of extremely precise Absolute Encoders. Absolute Encoders allow the mount to know its exact location regardless of accidental software errors and will allow it's recovery. This is particularly important in remote setups. Furthermore, they virtually eliminate periodic error, reducing it below 0.2 arcseconds in our tests. The encoders can be user installed on both axes, or on just the RA axis based upon the user's need. This frees the user from having to make the decision to include the encoders at the time of the mount's purchase; rather, they can be added later as need arises. Check out the 10 minute (600 seconds) unguided exposure by clicking on the thumbnail to the left.
Flexible Control with Your Keypad, Computer or even your Mobile Smart Device!
|As this chart shows, there are many options available for controlling your mount. Take a few minutes to link to descriptions of the varied software and devices that are available. You will be able to further link to a full size view of this chart and discover more about each method.|
Pier Mounting Options
The 1600GTO mount integrates a precision rotating pier adapter and azimuth adjuster as part of its base. The mount's base will directly attach to the Astro-Physics pier, or it can be attached to any flat surface using the Flat Surface Adapter for 1600GTO and
all 1200 Mounts (1612FSA). When choosing the Advanced Telescope System's (ATS) Pier, you will need to order our Flat Surface Adapter with Flat Pier Plate 1612FSA-FP that will fit into the top of their pier. The 1600GTO's large adjustable 0 to 78 degree latitude range (which spans from Antarctica to the arctic circle) makes the use of a wedge unnecesary.
1600GTO - What's Included?
Additional Accessories to Consider
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Inc. - All Rights Reserved
This page was last modified: February 21, 2014
11250 Forest Hills Road, Machesney Park, IL 61115, U.S.A.
Phone: 815-282-1513 Fax: 815-282-9847