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The Dual CCD ST-8XME and the Single CCD ST-8XMEI
Like the ST-10XME and ST-7XME, the new ST-8XME is based upon Kodak's latest microlens technology that increases the effective QE
of the CCD. The KAF-1603ME is now available for the model ST-8 cameras. This CCD features a peak QE of nearly 85%, 1530 x 1020
pixels at 9 microns square, and multiple AR coatings on the CCD window for increased light transmission and significantly reduced
reflections. The ST-8XME camera also includes a TC-237H CCD with 657 x 495 pixels at 7.4 microns for self-guiding. The ST-8XMEI is
intended for industrial use. It is a single sensor camera with no guiding CCD. Although it is intended for industrial
applications, it is also an excellent lower price alternative for astronomy where an external guider is used. Both models are
available with a Class 1, 2, or 3 CCD. Other than the cosmetic specifications, the Class 3 ME CCD has the same low noise and high
QE as the Class 2 and Class 1 versions. All ST-8 camera models use the same electronics and fast USB 1.1 interface.
For years, the model ST-8 camera was the flagship of the SBIG self-guiding models. This position was eventually taken over by the
higher resolution ST-10XME and more recently by the much larger STL-11000M cameras, but the ST-8XME still has its place. At 100
inches or more of focal length, the 9 micron pixels of the ST-8XME each see about 0.7 arcseconds. It is unlikely that during
typical seeing conditions where the FWHM of star images on long exposures are generally greater than 2.5 arcseconds, the smaller
pixels of the ST-10XME will improve on the resolution of the ST-8XME at this focal length or longer, and while the ST-10XME will
produce an image with twice as many pixels, the field of view is nearly the same. Also, the ST-8XME is well suited to TDI
imaging.
Alan Holmes has written an Application Note about TDI Imaging and Research applications that are perfect for the ST-8XME and
ST-8XMEI cameras. TDI is particularly interesting because one can image large areas of the sky without guiding so any telescope
will do. TDI stands for Time Delay Integration. Basically, one points the camera at an area of sky and turns off the telescope
drive to let the stars drift across the field of view. The CCD is clocked in sync with the rate of drift and 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. But there is no periodic error and no guiding error! Furthermore the image can just scroll as the
sky moves past so the image file can be 1020 x 1000 or 1020 x 2000 etc. One gets a deeper image with a more sensitive CCD. In the
case of the ST-8XMEI the extra QE of the microlensed CCD make it quite sensitive to dim objects and very good wide field astro
images can be created with no tracking at all. All of this means the ST-8XME might be the best choice for imaging through longer
focal lengths or for unguided TDI imaging at a significant savings compared to the ST-10XME.
Other than the QE of the CCD, the ST-8XE and ST-8XME cameras are identical. A table comparing the features of the ST-8XME and
ST-8XMEI can be found below.
Improved Features
Large Built-In Tracking CCD: The Self-Guiding model uses the TC-237H tracking CCD which is now standard in all of
our self-guiding cameras. The TC-237H array is 657 x 495 pixels at 7.4 microns. The TC-237H is 2.7X larger than the TC-211 CCD
which means there is a more than double the chance you will find suitable guide stars anywhere you happen to be looking without
having to hunt. In the tracking configuration, the TC-237H CCD will normally be binned 2x2 for increased sensitivity. When binned
2x2 the field of view remains 2.7X that of the TC-211 however as the pixel size is increased to 14.8 microns. The user may also
use the TC-237H CCD in high resolution (unbinned) mode if desired. ThsSky software from Software Bisque automatically generates
finder charts showing the correct placement of the guiding CCD field of view relative to the imaging CCD's field of view. Using
this tool to plan your nights imaging is a great compliment to the self-guiding cameras. When guiding with the TC-237H tracking
CCD, the imaging CCD spends 100% of its time and quantum efficiency gathering the image. You are not required to compromise by
giving up half of the quantum efficiency or by making twice the exposure time as you might with other self-guiding designs.
Upgradeability: The standard ST-8XME comes with a Class 2 CCD with no column defects. This model may be upgraded to
a Class 1 CCD if desired. The lowest priced ST-8XMEI is based on a Class 3 CCD. It may also be upgraded to a Class 1 or 2 CCD,
and/or to a dual CCD camera for self-guiding at any time. Current owners of ST-7 and ST-8 cameras may upgrade to the ST-8XME if
they already have USB electronics. The cost to upgrade the CCD only is $3995. Others may upgrade to USB electronics and ME CCD at
the same time for an additional $995. Adding the TC-237H guiding CCD to a USB camera (or concurrent to a USB upgrade) costs $395.
Final upgrade costs depend on the existing camera configuration. Check with SBIG for the latest upgrade pricing.
Improved Carrying and Storage Case: The ST-8XME model includes a high quality carrying and storage case made for
SBIG by Pelican. The custom cut foam securely holds the camera and power supply with additional spots for accessories, cables,
etc. The case is dust proof, water proof, crush proof and carries a lifetime guarantee from the manufacturer. The case is optional
for the ST-8XMEI.
Accessory Test Lens: To make testing of the camera easier we have designed a simple test lens that screws into the
t-thread front end of the camera. This is a handy accessory for learning the various camera functions in the day time if you do
not have a camera lens adapter. It is included with the Deluxe model and can be added to the Standard and "I" models. See our Test
Lens Product Announcement for more details.
Optional Accessories: The ST-8XME cameras support a variety of professional accessories. Each model contains a ROM
programmed to support the CFW8A Color Filter Wheel for automatic RGB or LRGB imaging when attached to the camera. Each model also
has electronic relays built-in so that the cameras can be used as autoguiders for film astrophotography or for guiding other CCD
cameras. The built-in TC-237H guiding CCD in the ST-8XME model enables the use of both the AO-7 Adaptive Optics Device and the SGS
Self-Guiding Spectrograph. The Self-Guiding Spectrograph was designed to give maximum resolution with 9 micron pixels. Several
camera lens adapters are available from SBIG for attaching a variety of 35mm camera lenses directly to the ST-8 without the filter
wheel for wide field imaging. Third party manufacturers support the ST-8XME and CFW8A color filter wheel combination with camera
lens adapters as well.
Each ST-8XMEI camera includes the following:
* Rugged camera body with new high speed analog and digital electronics
* New High QE Class 3 KAF-1603ME imaging CCD
* High speed USB interface (full frame download in ~ 3.6 seconds)
* New I2C bi-directional expansion port
* Standard accessory / telescope port
* User rechargeable desiccant plug
* Internal shutter
* 1.25" Nosepiece
* Cooling Fan - on/off controlled by software
* Tripod mount 1/4-20 threaded side plate
* Adjustable t-thread ring
* 15 foot USB cable (third party USB extenders available for up to 500 meters!)
* Universal Power supply
* SBIG's CCDOPS version 5 camera control software
* Software Bisque's TheSky version 4, level II
* Operating Manuals on CD-ROM
* One Year Warranty Parts and Labor
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