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Improved Quantum Efficiency
In 2003 Kodak released a new version of the CCD we use in the ST-7XE cameras. The new detector is designated the KAF-0402ME. This
CCD has the same array architecture as the KAF-0401E NABG with some improvements. Of greatest significance is the increased
quantum efficiency due to the addition of a microlens array over the pixels and the use of MAR coated cover glass. The same kind
of improvement has already met with great success in the ST-10XME camera. The peak quantum efficiency for the KAF-0402ME used in
all three models of ST-7XME cameras is almost 85%. They are the most sensitive CCD camera in their class. The QE for the blue
wavelength of 400 nm is 50% higher than that of the previous KAF-0401E CCD (increased from 30% to 45% absolute QE) and 15% higher
in the red spectrum near H-alpha (increased from 72% to nearly 85% absolute peak QE).
The resulting high QE from UV to IR makes the ST-7XME perfect for imaging deep space objects such as dim galaxies and emission
nebula. By fortunate circumstance, the peak QE occurs very near the H-alpha emission line at 656 nm, making this camera
extraordinarily sensitive at this important wavelength. It could be said that these camera was "made for" capturing H-alpha!
Previously, this level of QE was achievable only through the process of thinning the wafer and illuminating the image sensor from
the backside. However, thinned, back-illuminated CCDs are very expensive, but with the KAF-0402ME, similar performance to a
back-illuminated CCD is achieved with lower dark current and superior cosmetic specifications in a full frame front illuminated
detector.
With our latest high speed electronics and USB interface, these ST-7XME cameras will download a full frame image in 1 second!
Partial frames and focus mode will update faster than once per second. Imagine focusing in full frame mode. Kodak CCDs are well
known for their low dark current and low noise characteristics. Additionally, the Standard and Deluxe models have superior cooling
with a water assist ready heat exchanger built-in.
The KAF-0402E CCD, without microlens, is also available as an alternative to the microlens part for applications where a
microlens may not be desired. The QE for the KAF-0402E CCD is essentially the same as for the previous KAF-0401E. The difference
is the addition of greater static protection. The ABG version of this part, the KAF-0401LE remains unchanged. While we recommend
that our customers select the ST-7XME for astronomy, we will continue to offer the ST-7XE NABG and ST-7XE ABG so long as Kodak
continues to manufacture these varieties of the CCD.
Owners of ST-7XE cameras (USB interface and E detector) may upgrade to the new ME CCD. Owners of ST-7E cameras (parallel
interface and E detector) may upgrade to the ME CCD only (keeping the parallel interface) for or upgrade to both USB interface and
ME CCD at the same time. However, since we no longer make parallel electronics that support the E detectors, owners of the
original ST-7 model camera (non-E detector) must also upgrade to USB electronics in order to support the ME CCD.
Improved Features
Larger Built-In Tracking CCD: The TC-211 tracking CCD has been replaced with a larger TC-237H in the ST-7XME Standard and Deluxe
models, as we have done in the ST-8/9/10/2000 cameras. The TC-237H array is 657 x 495 pixels at 7.4 microns. This is the same CCD
used in our former $1300 ST-237A imaging camera and current $2300 STV autoguider. 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.
Built-in
Autoguider | Array | Pixel Size | CCD Dimension | CCD Area | Field of
View
at 80" FL | Number of
Pixels |
| TC-237 CCD | 657 x 495 | 7.4 x 7.4 u | 4.9 x 3.7 mm | 18.3 mm2 | 8.2 x 6.2
arcminutes | 325,215 |
| TC-211 CCD | 192 x 164 | ~ 15 x 15 u | 2.6 x 2.6 mm | 6.8 mm2 | 4.5 x
4.5
arcminutes | 31,000 |
Of course, guiding with the TC-237H tracking CCD means that 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: Each of the the ST-7XME models is upgradeable. This is particularly important to new buyers or
anyone who wants to pay as they go. For example, the low cost ST-7XMEI can be upgraded with a built-in tracking CCD or a Class 1
imaging CCD. It can even be upgraded to an ST-8XE or ST-9XE at a later time. This allows the new user to get his feet wet without
paying for a deluxe system all at once.
Improved Carrying and Storage Case: The Standard and Deluxe model ST-7XME cameras now include the same high quality
carrying and storage case as the rest of our ST line of cameras. This case is made for SBIG by Pelican. The custom cut foam
securely holds the ST-7 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.
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.
Each ST-7XMEI Special camera system includes the following:
* Rugged camera body with new high speed analog and digital electronics
* New High QE Class 2 KAF-0402ME imaging CCD with no column defects
* High speed USB interface (full frame download in about one second)
* 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 |
