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                                            Equipment Description

The Observatory uses a 10 inch f/6.3 Mead Schmidt-Cassegrain LX200 telescope for all its work.  The telescope is permanently mounted on an equatorial wedge and remotely controlled by a computer located in a room about ten feet from the telescope.  All images are recorded using a Santa Barbara Instrument Group (SBIG) ST-7E CCD self guiding camera normally mounted at the telescope's prime focus.  The imaging CCD has 765 x 510 "9 micron" pixels which provide a 15 x 10 arc minute field of view (1.18 arc seconds per pixel) at the telescope's native focal length of 63 inches.  In addition the camera has a second smaller tracking CCD with 192 x 164 pixels mounted in a coplanar position adjacent to the imaging CCD.  This allows the tracking CCD to be used to precisely control the position of image during the exposure of the imaging CCD.  A SBIG CWF-8 filter wheel can be attached to the camera to obtain color images or to make photometric measurements.  The filter wheel can be equipped with a Johnson-Cousins UBVRI filter set for photometric measurements.  Also H-Alpha, various infra red, and other band pass filters can be inserted into the filter wheel as required.  Most filters were supplied by Schuler Astro Imaging (chetschu@concentric.net ). A Meade Series 4000 f/3.3  focal reducer can be attached to the telescope to increase the field of view to a measured value of 31 x 21 arc minutes (2.47 arc seconds per pixel) when used in conjunction with the filter wheel.  This gives the telescope an equivalent focal length of 30.5 inches.  Alternately a 3X Barlow can be inserted into the optical path to increase the focal length to approximately 180 inches (0.4 arc seconds per pixel) for planetary observations.  A SBIG AO-7 Adaptive Optics system is used in conjunction with the camera to optimize image resolution.   For fine camera focus adjustment a JMI motorized focuser with a 2' barrel is attached to the visual back of the telescope.  A digital readout motor controller is used to focus the camera from the control room.  The focus can be adjusted over a distance of 12 mm to +/- 0.01 mm with the controller.   For coarse focus a JMI  electronic focus motor (MFL200) is attached to the focus knob of the telescope.  This "Motofocus" unit is plugged into the focuser connector on the LX200 power panel.   This allows the coarse focus to be made using the Meade hand controller keypad.  The keypad is normally located in the control room adjacent to the computer.  This arrangement allows all telescope functions (pointing, focusing and imaging) to be performed from the control room.  A Kendrick dew cap is placed over the corrector plate during use and a Kendrick dew heater is attached to the telescope at the corrector plate.  A Kendrick dew controller powered by a 12 volt battery charger provides current to the corrector plate heater and the filter wheel heater described in the Equipment modifications section below when it is used. A Mylar aluminum laminated bag (Desert Storm Shield) is placed over the telescope and camera when it is not in use and a 25 watt light bulb is turned on to reduce condensation.

A 133 MHZ Pentium desktop computer with 84MB of memory and a 2GB hard drive is normally used to point the telescope and control the image acquisition process.  The CCD camera is attached to the computer's parallel port with a thirty foot cable and the computer's serial port is connected to the RS-232 port thru a 100 foot 6 wire modular telephone  cable.  In addition the camera is connected to the CCD port on the telescope with a short 6 wire modular telephone cable.  Microsoft Windows is the operating system for the desktop.  A program called "The Sky" from Software Bisque is used to position the telescope.  Three other programs from Software Bisque  "T Point", "CCD Soft" and "Orchestrate" when linked to "The Sky" allow the accurate automated acquition of a preselected set of images.  This process is described in the Operations section.  A 400 MHZ Pentium II computer is used to process the images.  The more powerful Pentium II is preferred due to the extensive computations which can be required to optimize the images.  The image data is transferred between the PC's with a 1 GB portable hard disk.  Two programs are primarily used for data reduction.  MIRA AP6 from Axiom Research and Maximum DL Version 2 from Diffraction Limited.   The image tools and results are described in the Processing section.  Processed images and original data are archived on CD's for future reference.

A Self Guiding Spectrograph (SGS) manufactured by SBIG is used to obtain spectra of stars and nebula.  The spectrograph has a signal to noise ratio (S/N) of 5:1 for a magnitude 10 star when exposed in the high resolution mode (dispersion of 0.1 nanometers per pixel) for 10 minutes.  The wavelength range is 380 to 750 nanometers with full sensitivity but the unit will operate with reduced sensitivity up to 1000 nanometers.  Long exposures (up to an hour) can be obtained by using the self guiding mode which used the tracking CCD in the camera to keep the star precisely positioned on the 25 micron slit.  In the low resolution mode (0.43 nanometers per pixel) a magnitude 13 star can be measured with the 5:1 S/N in one hour. The program CCDOPS  version 4.1 from SBIG is used to control the camera when the SGS is in use and the image of the spectra is analyzed using a program called Spectra also from SBIG.  Spectra does the calibration the spectral image and produces a text file of the data.  Microsoft Excel is then used to graphically display the data.  A more detailed discussion of the use of the spectrograph and numerous spectra taken with the instrument are in the Spectroscopy section

Equipment modifications-  Several modifications have been made to improve performance of the observatory equipment.  A 6 inch bolt with a spring has been added to the secondary mirror of the telescope to reduce mirror flop.  This modification is described in detail on Chris Vedeler's web site.  (Dr. G's Info site and the Meade Advance Products Site also have useful information on modifications to optimize astronomical equipment.)  A heater has been added to the filter wheel to optimize operation when the temperature is below zero degrees Centigrade.  The heater consists of a 5 inch Kendrick  dew heater which is wrapped around the outside of the filter wheel and a eyepiece dew heater strap that is attached to the face of the filter wheel.  A cardboard disk is inserted between the filter wheel and the camera to further thermally insulate the filter assembly.  The Spectrograph has been modified to enhance its remote operation.  A neon bulb has been attached to the diffuser and is controlled by a switch in the control room.  This allows calibration spectra to be obtained when required without being present at the telescope.  Second a toggle switch was wired in parallel with the switch on the spectrograph to allow the LED which illuminates the slit to be controlled remotely.  Both sets of wires are interfaced with connectors allowing convenient removal of the spectrograph when not in use.