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Software Bisque's new
telescope mount combines state of the art automation with rock-solid stability. text by Gregory Terrance and digital web photos by Software Bisque | ||
A telescope is only as good as the mount that holds it. That statement may surprise some, but most experienced observers will agree. You cannot have an enjoyable, frustration-free time viewing the night sky with a telescope if it rests on a jittery mount. My first telescope was held by just such a mount. It had outstanding optics that were great for observing the moon and planets. Unfortunately, the tube assembly was more impressive than the mount - a fork-mount that shook every time I touched the focuser. To make matters worse, the mount's poor drive system completely frustrated my initial attempts at taking guided deep-sky astrophotos. To get the most from a telescope, it has to be matched with a solid mount, one suited to your specific astronomical needs. Visual astronomers can get away with simple, but sturdy, alt-azimuth mounts like the Dobsonian. An astro-imager, on the other hand, needs an equatorial mount preferably one with a quality drive system. Software Bisque's Paramount GT-1100 robotic mount is a solid telescope platform endowed with a superb drive system. Consider it a "new-age" German equatorial mount that is tailor-made for advanced astro-imaging. The Paramount comes with software that, among other things, allows it to be controlled from the cozy comfort of your den or home office. The telescope can also be accessed and controlled through the Internet. The mount and software are an impressive combination. There are enough advanced features to satisfy the most voracious imager well into the next millennium. The Paramount GT-1100 makes home-dome automation a reality. This professional-quality mount offers amateurs the capability to remotely access the telescope and CCD camera, while combining stability with precision pointing accuracy. |
The GT-1100 combines high-quality components with top-notch machining. It is capable of professional levels of pointing accuracy (better than one arc-minute across the entire sky) and has variable slew rates of up to 2' per second. Fully assembled, the mount (right ascension housing, declination housing, and declination shaft) weighs slightly more than 100 pounds and can effortlessly carry a telescope in the 75-pound range. It is supplied with a six-button, multi-functional hand controller and two nickel-plated counter weights totaling 50 pounds. A solid 1.5-inch stainless-steel shaft is used for both the declination and right ascension axis. The right ascension axis uses a precision, research-grade Edward Byers' 11.5-inch gear with a tracking accuracy of five arc-seconds or better - this is before the Paramount's permanent periodic error correction is applied. A 7.5-inch Byers gear is used for declination control. Both are driven by stainless-steel worm gears with 60-ounce-per-inch stepper motors. All of the drive components (motors, worm gears, and drive gears) are protected with aluminum covers. The Paramount can be pointed by a computer or with the supplied hand controller. Mechanical slow motion controls and clutches are not used since TPoint (see "Professional Astronomy Software Suite" requires the gear-to-worm synchronization of both axes be maintained. These operating restrictions mean the mount cannot be pointed manually. The polar alignment accuracy and right ascension gear quality of a telescope system ultimately determine how long an unguided exposure can be before star trails become noticeable. To simplify polar alignment, the Paramount is equipped with precision 80-pitch altitude and azimuth adjustment screws. Both screws have a known effect on the mount's movement: five arc-minutes per rotation and six | |
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you do not have to
understand all of the software features to get started.
USING
THE PARAMOUNT
STABILITY |
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arc-minutes per rotation,
respectively. These calibrated fine adjustments make the polar alignment
process much easier, user friendly, and predictable.
As an aid for remote operations, the GT-1100 uses an internal 168-pin ribbon cable to route all camera, telescope-scope, and miscellaneous inputs through the mount. This eliminates the chance of getting cables snagged or caught during an imaging session. Inputs are plugged directly into the instrument panel (located below the mounting plate) and routed to the base panel where they are reconnected to the correct device. With the Paramount's internal cabling, a completely outfitted telescope with an electric focuser, dew heater, and CCD camera, can be used without any cables droop-drooping to the observatory floor. |
Paramount's
research-grade 11.5-inch Byers gear keeps your scope's right ascension
tracking to within five arc-seconds or better.
PARAMOUNT SOFTWARE The Paramount is supplied with a Professional Astronomy Software Suite (PASS) - a personal computer running Windows 95 or Windows NT is required. Included in the group are TheSky, CCDSoft, TPoint, and Orchestrate. With these programs and a GT-1100 mount, an astronomer can take complete control over the imaging system (telescope, mount, and CCD camera) for un-attended, robotic operations. With PASS it's possible to take hundreds of CCD images in one night without ever leaving the computer or touching the telescope. The cost of such technology is a steeper-than-normal learning curve. Fortunately |
Basic "tap-tests" were performed to determine its damping capabilities. Using an eyepiece that yielded a 95x magnification, a sharp rap with my knuckles on the telescope's focuser took between one and one-and-a-half seconds to stabilize. Some of the vibrations were caused by the telescope-scope's tube, which was made from thin aluminum. POINTING ACCURACY Many Go-To mounts boast impressive pointing capabilities - but only if they are recalibrated to a nearby star each time the mount is aimed to a new region. The Paramount avoids the hassle of such resynchronization. Instead it relies on its' software, drive Additions like a CCD camera, video camera, and dew heater can all be accommodated by the Paramount's instrument panel. |
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system, and polar alignment capabilities. In initial tests, the mount constantly placed objects within two to five arc-minutes of the field's center. That's not bad, considering I did not have perfect polar alignment. I was able to lower these figures by improving the mount's polar alignment and employing the error-correcting abilities of TPoint. After some fine-tuning, the telescope's pointing accuracy improved to better than two arc-minutes. Impressive. Then TheSky was used to point the telescope at a dozen different deepsky objects; 30-second CCD images showed the galaxy or nebula dead center each time. DRIVE ACCURACY Since the Paramount was built around the concept of imaging productivity and robotic operation, it had to have a superior right ascension gear system. Otherwise, tracking errors would ruin unguided images. Did it |
Make your rough polar
alignments with the right ascension housing nuts (two on each side of the
wedge) and the two shoulder bolts at the base of the wedge. Fine
adjustments are made with the altitude adjustment screw (center of the
bar) and the azimuth knobs that extend from both sides of the wedge at its
base (bottom-center of photograph).
deliver? You bet. The Byers right ascension drive claims a periodic error of five arc-seconds or better. My tests showed this to be true. SLEWING The Paramount has a maximum slew rate of 2 degrees per second, which is slower than other systems that I've encountered. Even so, most objects were located and centered in less than 60 seconds. For instance, I used the stars in Orion for my first mapping session; the Paramount took about 19 seconds to travel from Betelgeuse to Rigel. The longest slew times (more than 150 |
seconds from Bellatrix to Sirius)
resulted when the mount had to "flip" itself to reach objects on the other
side of the meridian. Noise levels for all slew speeds were kept to a
minimum. |
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P R O F E S S I O N A L A S T R O N O M Y S O F T W A R E S U I T E |
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What follows is a brief description of the software included with the Paramount system's package. |
TheSky (Level IV) TheSky is a planetarium-style computer program that places the cosmos at your fingertips. Use it to view the night sky at any time or date, and from any location. It includes an astronomy tutorial, solar system viewer, conjunction finder, star chart maker, object database, and much more. TheSky is the main program in the suite and is used to set up and control the Paramount. One example of how the program interfaces with the Paramount is its "park" feature. The park command sends a series of instructions to move the Paramount to a park position. Subsequent imaging sessions can be auto-started without any alignment procedure -a great feature for remote, unattended imaging. CCDSoftThis program is an image-acquisition and image-processing package. It has all of the tools needed to acquire and process CCD images. It also includes a tutorial for beginners. Many other features - like tri-color assembly, auto-guiding, registering multiple planetary images, photometry, and more |
A software "scripting" tool used to set up and run automated imaging sessions, Orchestrate controls TheSky, CCDSoft, and the Paramount. It enables the mount to find an object, then tells the camera to take an image. Once the exposure is complete, Orchestrate uses TheSky to slew the mount to the the next object. Because image selection can be preprogrammed, the telescope and CCD camera operate without delay. This makes Orchestrate a wonderful tool for maximizing imaging sessions, and it's all accomplished whether the GT-1100 is in your backyard or in another state. TPointAll telescope systems suffer from pointing inaccuracies due to polar misalignment and mechanical errors. TPoint is an error modeling program that can compensate for errors and dramatically improve a system's pointing capabilities
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TPoint also helps the telescope attain optimum polar alignment. I had a lot of fun with this feature - its ability to reveal a mount's deviation from true celestial north was fascinating. Polar misalignment figures, in altitude and azimuth, were report in arc-second increments. For example, I initially polar aligned the Paramount using the star-drift method. My first mapping session indicated I was 650 arc-seconds above and 250 arc-seconds east of the North Celestial Pole. These values dropped as I adjusted and improved Paramount's polar alignment. TPoint reduced the time required to fine-tune a mount (compared to traditional methods), but its real value was the ability to provide quantitative feedback and deadly accurate results.
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Even with a three-pound CCD
camera attached, the drive motors never sounded strained and the gear
system did not exhibit any chatter. With all of its hardware and software capabilities, the Paramount can be considered an ultimate imaging machine. Compared to the high quality German equatorial mounts that I've used for the last decade, it almost makes CCD imaging easy. Certainly, in these days of $400 eyepieces and $6,500 CCD cameras, the Paramount rates as something of a bargain at $9,500. Although the cost will place it out of reach for many individual astronomers, it is a reasonable investment for small colleges, astronomy clubs, or a group of enthusiastic astro-imagers. Not only does the price of admission get you a complete telescope mount, with nearly unlimited imaging capabilities, it also buys a suite of software that covers every imaging need from Acquire to Zoom. Gregory Terrance is an astro-imager linving in New York. Visit his website at http://www.frontiernet.net/~gregoryt/
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Hardware Weight: 45 kg (100 lb) without optical tube assembly or counterweight 34 kg (75 lb.) instrument capacity 1 -inch stainless steel right ascension 11.5-inch Byers research-grade right Calibrated 80-pitch thread altitude 22.7 kg (50 lb.) counterweights Control System Six-button, multi-function hand controller Internal wiring for mount control, parallel TCE-1 Motion Control System from Auto-guider input port 60 inch-ounce stepper-motor Variable slew rates up to 2 degrees per second
Simultaneously control both a parallel port camera (ST-7, ST-8, TC-255) and the mount with a single parallel port Auto start capability Visit Software Bisque's website at http://www.bisque.com/ for more details. |
