| The ST-8XMEI is a large format single-detector CCD camera only. It does not have the built-in second detector for self-guiding the camera that comes with the ST-8XME itself. However, the ST-8XMEI can be upgraded to a dual-chip self-guiding camera at any time, simply by having SBIG add a guiding detector to the camera body. In addition, the ST-8XMEI has a remote guiding head port that allows you to use an existing smaller SBIG CCD camera, such as an ST-402XME, as a guider for long exposure imaging. SBIG also makes an optional #RGH Remote Guiding Head that can used to guide the ST-8XMEI using an off-axis guider or separate guide scope. The ST-8XMEI is an excellent camera for most astrophotographers. With a telescope focal length of 2500mm (a 10" f/10 Schmidt-Cassegrain), the 9-micron pixels of the ST-8XME each see about 0.7 arc seconds of sky, very close to the half arc second of sky per pixel considered optimum for high resolution lunar/planetary/binary star imaging. With an f/3.3 focal reducer in place, each pixel sees 2.12 arc seconds of sky through the same scope, very close to the 2 arc seconds per pixel considered optimum for imaging faint deep space objects. Put the camera on a 4" f/8 refractor and each pixel sees 2.21 arc seconds of sky, again very close to the optimum for deep space imaging. Also, the ST-8XMEI is particularly well suited to TDI (Time Delay Integration) imaging. TDI lets you image large areas of the sky without guiding – so any telescope will do. In TDI, you point the camera at an area of the sky and turn off the telescope drive to let the stars drift across the field of view. The imaging detector is clocked in sync with the rate of stellar drift to keep the accumulating charge underneath the star’s image until the star reaches the edge of the CCD, and the readout register. The resulting image has an exposure time equal to the amount of time it takes the stars to drift across the CCD. Depending on the focal length of the scope, this can be many minutes. Because the scope itself is not moving, however, there is no periodic error and no guiding error during the exposure! Furthermore, the image you are recording scrolls as the sky moves past, so the image file can be 1020 pixels tall by 1000 pixels in width, or 2000 pixels wide, or 3000, etc. The imaging CCD is the new enhanced Kodak KAF-1603ME Class 2 chip with microlens technology. This technology provides much higher quantum efficiency (QE) across the entire UV to IR spectrum than previous detectors. The high QE makes the ST-8XMEI perfect for imaging deep space objects such as dim galaxies and emission nebula. Peak QE occurs very near the H-alpha emission line at 656 nm, making this camera extraordinarily sensitive at this photographically important wavelength. It could be said that the ST-8XMEI was “made" for capturing H-alpha. Previously, this level of QE was achievable only through the process of thinning the detector wafer and illuminating the image sensor from the backside. However, thinned and back-illuminated CCDs are very expensive to make and buy. With the KAF-1603ME front illuminated detector, similar performance to a back-illuminated CCD is achieved with lower dark current and superior cosmetic specifications (the number of pixel defects) – and at a much lower cost. Peak quantum efficiency is almost 85%, making this camera the most sensitive in its class. In order to provide the largest full well capacity for linear response scientific measurements and the widest dynamic range for imaging, the ST-8XMEI does not have built-in antiblooming (ABG). Kodak classifies their imaging detectors according to the number and type of “defects" found on the chip. “CCD Point, Cluster, and Column Defects" are defined in the “Astronomical Terms" section above left. The Class 2 chip of the ST-8XMEI has no more than 10 point defects in its entire 1.5 megapixel imaging area (no more than 5 in the central 600 x 800 pixel area); no more than 4 cluster defects (a maximum of 2 in the central 600 x 800 pixel area); and no column defects. The few point and cluster defects of the ST-8XMEI are easily removed from an image during processing. Carefully guided exposures up to one hour are possible with the ST-8XMEI, enabling a standard 8" Schmidt-Cassegrain to capture images showing 19th magnitude stars from typical background observing sites. Pixel binning modes (1x1, 2x2, 3x3) allow the user to match the pixel size to various focal lengths ranging from long focal length refractors and SCT's to short focal length camera lenses. The imaging camera includes a mechanical shutter, 16-bit analog to digital (A/D) converter, regulated temperature control, and has all of the electronics integrated into the CCD head. Communication to your PC is through new high speed electronics and a high speed USB 1.1 interface. Data transfer rates are up to 420,000 pixels per second, allowing a full frame download in 3.7 seconds (images download at approximately 2 per second in the focusing mode). The standard cooling configuration is a single stage thermoelectric cooler with an active fan and a newly designed heat exchanger. It includes an inlet and outlet for water circulation should the user desire to maximize the cooling performance for hot climates. Typical cooling without water assist is -35° C from ambient (-30° C minimum). With water assist, the cooling increases to a typical -45° C. Even without water cooling, the new single-stage cooling design offers similar performance to previous two-stage cooling with much less current draw than a two-stage cooler. It is therefore less demanding on battery capacity when operating in the field. A circulating water pump and tubing are available as optional accessories. The camera body has the above-mentioned Remote Guide Head port for using an external guider. There’s a new I²C accessory port that adds bi-directional communication capability for the coming development of a new family of "smart" accessories. A standard accessory port is also provided to maintain compatibility with the customer's existing telescope interface cables and backwards compatibility with SBIG’s existing accessories – such as the CFW8 color filter wheel, AO-7 adaptive optics system, etc. The camera body has rack handles that make for easier and safer handling of the camera, particularly in cold weather when wearing gloves; a high-speed USB 1.1 interface port; a user-rechargeable desiccant plug (there’s no need to return the camera to the factory for frosting problems); an internal shutter for automatic dark frames; a 2" nosepiece (a 1.25" nosepiece is optional); a T-thread ring for attaching to T-mount photo accessories; a 1/4"-20 thread side plate for tripod mounting; a 15-foot USB cable (third party USB extenders with a CAT5 cable are available for cable runs up to 300 feet); an adapter plug for the telescope interface cable; a telescope interface cable for autoguiding; and a universal 90-240VAC power supply with a remote on/off switch. You also get a CD-ROM containing full working versions of SBIG's CCDOPS version 5 camera control software, Software Bisque's CCDSoft Version 5 image processing/camera control software, and Software Bisque's TheSky version 5, level II, with telescope control for Windows. All operating manuals are on the CD-ROM. A custom designed hard carrying case with pre-cut foam is available as an option. While the software supplied with this camera is designed for use with a Windows-based PC, SBIG can also supply software to let Apple Macintosh owners control the camera. The software is available free from SBIG upon request to any new SBIG camera purchaser with proof of purchase. Simply send SBIG a copy of your invoice with the camera serial number and request the EquinoX Planetarium Software with SBIG Camera Control. The EquinoX software requires a Apple Macintosh computer (G3, G4 or G5), OS X 10.2 or later, 30MB of free RAM, and 92MB of hard disk space. The software can control all SBIG ST-series cameras and Ethernet cameras. OS X drivers for the cameras are also required and can be downloaded from SBIG at no charge. Detector specifications are as follows: Imaging Detector: Kodak KAF-1603ME, Class 2.
Pixel Array: 1530 x 1020 pixels.
Pixel Size: 9 x 9 microns.
Total Pixels: 1,560,600.
Full Well Capacity without ABG: ~100,000e-.
Dark Current: 1e-/pixel/second at 0 degrees C. Readout specifications are as follows: Shutter: electromechanical.
Exposure: 0.11 to 3600 seconds, 10ms resolution.
Correlated Double Sampling: yes.
A/D conversion: 16 bits.
A/D gain: >2.3e-/ADU.
Read noise: 15e- RMS.
Binning modes: 1x1, 2x2, 3x3.
Pixel digitization rate: up to 420,000 pixels per second.
Full frame acquisition: 3.7 seconds. Optical specifications with 8" f/10 (2000mm focal length) scope are as follows: Field of view: 24 x 16 arc minutes.
Pixel size: 0.9 x 0.9 arc seconds.
Limiting magnitude: magnitude 14 in one second.
Limiting magnitude for 3 arc second FWHM stars: magnitude 18 in one minute. System specifications are as follows: Standard cooling: single stage thermoelectric, active fan, water assist ready, -35° C from ambient typical (-45° C from ambient typical with water assist).
Temperature regulation: +/-0.1 degree C.
Power requirements: 5 VDC at 1.5 amps, +/-12 VDC at 0.5 amp desktop power supply included.
Computer interface: USB.
Computer compatibility: Windows 95/98/NT/2000/Me/XP. Physical specifications are as follows: Optical head: measures 5 inches diameter x 3 inches deep (12.5 cm diameter x 7.5 cm deep), weighs 2.2 pounds/1 Kg.
CPU: no separate CPU required, all electronics integrated into optical head.
Supplied mounting methods: T-thread, 2" nosepiece.
Back focus needed: 0.92"/2.3 cm.
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