Takahashi FCL-90 Guidingscope

Paramount-ME Robotic Mount

The Paramount ME's control system uses brush-less DC Servo motors. If the mount is used for survey astronomy all night, every clear night, no other type of motor is sufficient. Note that the life of the brush-less DC servo motor is limited to the service life of the bearings. This translates to about 100,000 hours under normal operating conditions. On the other hand, the life of brushed DC Servo motors is limited to the life of the carbon brushes, which is anywhere from 4,000-10,000 hours according to the manufacturer’s specifications.

Brush-less motor also do not "cog" at any rate. This ensures a smooth, constant output when tracking at the Sidereal rate.

• Brush-less DC-servo motors ensure long life and smooth operation.
• Field upgradeable flash RAM permits easy, immediate software updates.  
• Fast slew speeds and consistent torque at all slew rates. A maximum rate of five degrees per second in right ascension and seven degrees per second in declination gets you to the object, fast.
• Virtually unlimited selection of tracking and slew rates.
• AutoHome™ capability (to better than one arcsecond) with built-in sensor circuitry on each axis ensure that the mount always knows its orientation (after a one-time initialization), even after power failure.
• Software controlled "hard limits" prevent the mount from tracking or slewing into itself.
• User-defined parameters can be stored to on-board flash RAM.
• Numerous safety features critical to remote operation including current-limit protection, encoder-error limits, acceleration ramping, and user-definable maximum slew speeds.
• Joystick, TheSky for Windows or TheSky Pocket Edition control.
• Programmable and updateable Periodic Error Correction.
• Intelligent German Equatorial flipping eliminates unnecessary long slews.
• The MKS-3000 control system can track at true lunar, solar, minor planet or comet, NEO or LEO satellite rates, or at almost any user-defined rate (when used with TheSky). 
• TheSky has been updated to provide many new capabilities that were previously not possible. Some examples of these new features include: display a graph of the periodic error of the worm gear; track a low-earth satellite by clicking on the object on the Sky Display.
  

Figure 5. Mounting description (S. Bisque)

Performance Specifications:

• Periodic Error (Tracking) - The right ascension gear has 5 arcseconds periodic error or less, before periodic error correction and without ProTrack.
• Backlash - The spring-loaded worm-to-gear interface has virtually zero backlash in both the right ascension and declination axis.
• Pointing - Less than one arcminute RMS all-sky pointing. (Typical results vary from 10 to less than 60 arcseconds all-sky pointing. Results may vary depending upon the optical system, pier and other variables.)
• Homing - When permanently mounted, the Paramount ME can be restarted (powered off then on) with the identical pointing and tracking each night.

Robotic Control

The robotic control system allows the telescope to operate without supervision. This requires at a bare minimum:

• An automated telescope housing (dome or flat roof)
• A telescope with robotic telescope mount
• A CCD Camera
• A computer connection to a network/internet.
• Safety sensor (e.g. weather sensor)
• Remote Observing Software

The system proposed to BAKSA should work in three modes:

• Manual mode (the observer present at the observatory)
• Remote mode (the observer controll the observatory in real time from his/her home/office through internet line)
• Robotic mode (the observer from any place give the structured job using scripting language to the observatory and let the orchestrated system execute the job automatically).

Main CCD Camera: SBIG Research 1001E

This is the new research line of large format, dual head triple sensor, self-guiding CCD cameras from SBIG. The Research-1001XE utilizes the megapixel KAF-1001E "Blue-Plus" Enhanced CCD from Kodak. The CCD array is nearly 1” square with 1024 x 1024 pixels at 24 microns square and has the highest quantum efficiency of any KAF enhanced detector.

Figure 7. The camera CCD chips and electronics (SBIG)

Figure 8. The physical appearance of the camera (SBIG)

This high QE is not only in the blue but particularly in the red and near infrared. In addition to high QE, the low dark current characteristic of Kodak sensors and large pixel size means that the sensitivity and field of view of this detector compares very well to similar sized backlit sensors in cameras costing more than twice as much. The imaging area of this CCD array (24.5 mm x 24.5 mm) is nearly as large as a 35mm film frame.

Figure 9. CCD Chip KAF 1001E (Kodak)

At 2.54m focal length the detector has a field of view greater than 1/2 degree while each 24 micron pixel sees less than 2 arc seconds. This camera is ideal for supernova searches, minor planet searches, and general imaging using 10" F/10 and longer focal length telescopes. The imaging camera includes an electro-mechanical shutter, 16 bit analog to digital (A/D) converter, new design two-stage TE cooling with regulated temperature control and optional water assist, and all of the electronics are integrated into the CCD head. Communication to the PC is through the USB.

This camera is employed the internal TC-237 tracking CCD for guiding sensor.

An internal 5 position 2" filter carousel is integrated into the front cover of the camera body.  For color, UBVRI, or narrow band imaging simply add filters to the camera's carousel.   The filter carousel accepts both 50mm diameter flats and 48mm threaded filter cells.  The front cover of the camera is easily removed for changing filters.  Since the CCD is in a separate sealed chamber, removal of the front cover to change filters does not expose the CCD to dust or air and the desiccant does not need to be recharged after replacing the cover.  A shutter mechanism is also located inside the camera body, between the filter wheel and the sealed CCD chamber.

The standard cooling design utilizes a very efficient two-stage TE cooler for maximum performance with large format detectors.  Each camera is also liquid assist ready so that additional cooling in warm climates may be achieved by circulating water if needed. Preliminary tests indicate that cooling -50 Degrees C below ambient will be achieved with this system.   

This CCD will be the main instrument for Photometry and CCD Imaging.

The 5m ObservaDOME

Observa-DOMES are manufactured using advanced computer controlled cutting and fabrication equipment. The surface of the 5m dome is mill finish aluminum and 3003 H-14 alloy.The design is truly hemispherical, that is, circular in both plan and elevation and is capable of continuous clockwise or counter-clockwise rotation.

The dome is constructed to survive wind velocities, including gusts to 200km/h with the shutters closed and in storage position. It is capable of normal operation with wind velocities of 48 km/h, including gusts from any direction with the shutters open. The domes are capable of normal operation in temperatures from -6° C to 46° C. The domes are fabricated so that they are not subject to solar detraction or corrosive detraction. Also, it is fabricated to incorporate adequate expansion joints to prevent thermal distortion and further are leak proof and watertight when subjected to rain as may be experienced in a tropical downpour.

Observa-DOME / Meridian Controls Computer Automation Specifications

This computer automation system will allow complete operation of both the Observa-DOME azimuth drive, and dome shutter systems via computer control. It will be capable of interfacing with telescopes using software such as Software Bisque’s “The Sky”, or other compatible software.

Two electronic controller panels will be provided: one dome mounted controller to provide shutter operation, and the second stationary Dome controller, mounted below the rotating dome, for azimuth drive control, shutter command, telescope, computer interface, and power input, etc.

Figure 15. Automation module mounted on rotating dome (ObservaDome)

The Observa-DOME will be driven in azimuth by a closed-loop, DC gear motor driven, control system. A heavy-duty roller chain will be attached to the dome tension ring drive band and actuated by a sprocket attached to the DC azimuth gear motor. An encoder attached to the azimuth gear motor will provide azimuth position feedback.

The Observa-DOME bi-parting shutters will be actuated using 12 VDC gear motor and chain assembly. Limit switches will be provided for both the open and close shutter positions. The shutter gear motor will be powered by sealed 48-amp/hr battery attached to the rotating dome. The battery will be charged by a 30-watt solar panel attached to the exterior of the dome. Command for the shutter controller will be made by an RF data link to the stationary Dome controller. The shutters will close in the event of a power failure at the dome controller.

The computer automation package will allow normal Observa-DOME operation controlled locally, or via the Internet or LAN.

Dome opening and closing will require less than 30 seconds. Complete system initialization will require less than two minutes. The Observa-DOME azimuth position, velocity and acceleration will be fully programmable.The Observa-DOME will track at a sidereal rate when used with Bisque’s “The Sky”.