STXL-16200 / AO-X / Self-Guiding Filter Wheel Package:
SBIG has a history of quality and value in their CCD cameras, and this amazing package deal takes that value and quality both even further beyond what's considered normal, reaching a whole new level! SBIG has packaged their STX 16803 with not just one, not just two, nor even just three extra items; no, they've packaged their camera with no less than seven separate items, not even counting the camera itself!
SBIG STX CCD Camera Highlights:
- USB 2.0 and Ethernet on each camera
- 12VDC Operation (Operates from 9 - 14VDC)
- Full Frame Image Buffer
- Multiple A/D Channels
- Image and Guide While Downloading
- Internal and External Self-Guiding (with Remote Head)
- Simultaneous Dual CCD Guiding
- Differential Guiding (patent pending)
- Continuous Guiding During Autograb
- Adaptive Optics Control with Internal or External Guider
- Water Cooling Ready
- Even-illumination Mechanical Shutter
- User Rechargeable Desiccant Plug
- Relay LED Indicators
- Variable Speed Fan Control
- Focus Mechanism for Tracking CCD
- Opto-isolated Relays for Telescope Control
- Tracking Relay LED Indicators
- Power Management LED Indicators
New Guiding Techniques for the SBIG STX: The advantage of easier guiding through a separate guide scope is often limited by differential deflection of the guide scope relative to the main optical axis due to mechanical flexure or shifting of the mirror in the main OTA. This difficulty is addressed with two new guiding techniques developed by SBIG and implemented in the STX series cameras: Simultaneous Guiding and Differential Guiding.
Built-in Guiding CCD with Adjustable Focus: Simple self-guiding and control of the SBIG Adaptive Optics accessory using just the internal tracking CCD will be a standard feature. The guiding CCD in the STX cameras will be a new KAI-340 CCD with 640 x 480 pixels at 7.4u. As the imaging CCDs get larger, the guiding CCD gets pushed farther away from the center of the optical axis. Depending on the nature of the optical system, this can cause the image on the guiding CCD to be slightly out of focus when the image on the main CCD is in focus. To address this, the new STX cameras will have a user accessible adjustment for changing the focal point of the on-board guiding CCD.
Optional Remote Guide Head: A Remote Guide Head will be optional for the STX cameras. Self-guiding through a separate guide scope or off-axis guider, and control of the Adaptive Optics accessory can be done using the Remote Guide Head instead of or in addition to the onboard guiding CCD. The same KAI-340 CCD will be used in the new Remote Guide Head made for the STX series cameras.
Simultaneous Guiding: The external guide head will not only continue to guide while the imaging CCD is downloading an image, but it can be operated simultaneously with the on-board guiding CCD. This allows a unique type of guiding through a separate guide scope that will correct for differential deflection by using the external guider to make fast corrections while the onboard guider makes slow corrections. Differential deflection tends to occur over a longer period of time than drive errors, typically minutes vs. seconds. A long exposure taken with the built-in guider is capable of reaching dim stars without searching, even through narrowband filters, and a long exposure with slow corrections with this on-board guider will correct for the slow differential deflection typically experienced with a separate guide scope. In the meantime, the Remote Guide Head can simultaneously make fast corrections using the brighter stars easily found with a short refractor mounted piggyback to the main OTA. This technique developed independently is similar to the technique employed successfully by Italian amateur Filippo Ciferri using two separate cameras for which he deserves full credit. With the STX, however, a single camera and remote head will perform both the fast and slow guiding, as well as the imaging, all at the same time, using a single instance of the control software and only one connection to a computer.
Differential Guiding: SBIG has a patent pending on a new guiding technique using an artificial guide star. Although artificial stars are used in a variety of techniques on professional telescopes, the SBIG technique is somewhat different and easy to implement on amateur scopes. An artificial star is created near the focal plane of the imaging CCD and an image of this star is retro-reflected into a separate guide scope. By using one real star in the FOV of the guide scope and the artificial star image reflected from the main scope, the difference in separation caused by telescope pointing errors is used to make the corrections to the telescope drive. There is no problem with differential deflection and a single CCD external guider can be used to monitor both the real and artificial guide stars. The artificial star image is not seen by the imaging CCD.
Some Design Features of the SBIG STX:
- USB 2.0 and Ethernet: Both USB 2.0 and Ethernet will be available on each STX camera. The user will not have to choose the interface at the time of purchase. The STX cameras will have the same convenient I2C AUX port that SBIG uses on the ST and STL cameras for power and control of accessories such as filter wheels and Adaptive Optics, and will operate from any unregulated 12VDC source.
- 12VDC Operation: In similar fashion to the STL cameras, the STX will internally regulate a 12VDC supply so that the camera can be connected directly to any unregulated 12VDC source such as a car battery. The SBIG STX camera will have 4 power LEDs that will indicate if the supply voltage drops to 11, 10 or 9 volts and when it is "good." Operation of the camera is possible with a supply voltage of 9.1 to 14 volts DC.
- Full Frame Image Buffer: The STX series cameras will have a full frame image buffer for storing image data during download. The STX will be able to image during download process. We are exploring the possibility of using this buffer for pre-processing pixel defects based on a defect map provided by the CCD manufacturer, at the user's direction.
- Multiple A/D Channels: Having multiple A/D channels available makes a number of things possible. For instance, the STX cameras will be able to download and guide, or guide with two guiders all at the same time. Guiding can continue uninterrupted using the Remote Head during an auto-grab sequence, or an automated LRGB sequence, just as it would if you were using a separate camera or autoguider independent the camera.
- Improved Cooling: SBIG engineers have modeled an optimum cooling design for this camera using a large custom pin grid array heat sink mated directly to the hot side of the 2 stage TE cooler to achieve maximum heat dissipation with a single large fan.
- Water Circulation Ready: While the design is aimed at sufficient cooling without water assist, it is possible to use water instead of air or in addition to air for optimum cooling. Using water instead of air will not require the use of a fan. Chilled water may also be used alone or with the fan for even greater cooling.
- Even-illumination Shutter: Starting with the first ST-7 camera, SBIG has incorporated an even-illumination shutter for taking short exposure flat field frames on all self-guiding cameras. However, the rotating disk design becomes rather large with ever increasing CCD sizes. Therefore, a new shutter design will be introduced with the STX series that reduces the overall size and weight of the camera body, while maintaining even illumination on short exposures with large CCDs.
- Variable Speed Fan Control: If the user desires air cooling only, the fan speed is controllable through software. Variable speed control allows the user to tune to fan to eliminate any resonance with the user's telescope thus suppressing harmonic vibrations.
- Focusing Mechanism of Tracking CCD: As CCDs get larger, the tracking CCD is moved farther off-center from the optical axis. This can result in out-of-focus guide stars. In order to compensate for different telescopes and different tracking CCD locations, the built-in guider will have a small, user accessible, focus adjustment for the tracking CCD. Once this is set for a particular camera and scope combination, it will not be necessary to change it.
- Opto-isolated Relays for Telescope Control: These isolated relays will not require an external Relay Adapter box or another opto-isolator to work with virtually any telescope mount that accepts autoguider inputs for guiding control.
- Tracking Relay LED indicators: This handy set of 4 LEDs will tell you at a glance if the camera is issuing corrections to the mount in +X, -X, +Y or -Y directions during an imaging session.
- Adaptive Optics and Filter Wheels: Due to the sizes of some of the planned CCDs, a new AO and Filter Wheel will be designed for the STX cameras. Filters for most of these chips will need to be larger than 1.25-inch. Some need to be larger than 2-inch or 50 mm round.
About the Kodak KAF-16803 Monochrome Sensor: The KAF-16803 image sensor is a redesigned version of the popular KAF-16801E image sensor (4096 x 4096-pixel resolution) with enhancements that specifically target the needs of high-performance digital radiography applications. Improvements include enhanced quantum efficiency for improved DQE at higher spatial frequencies, lower noise for improved contrast in areas of high density, and anti-blooming protection to prevent image bleed from overexposure in regions outside the patient. Utilizing Kodak's proprietary single gate ITO process and micro-lens technology, the KAF- 16803 image sensor with its large imaging area and small pixel size provide the sensitivity, resolution, and contrast necessary for high-quality digital radiographs. To simplify device integration, the KAF-16803 image sensor uses the same pin-out and package as the KAF-16801E image sensor.
From the intricacies of microscopy to the far reaches of astronomy, KODAK Full Frame CCD image sensors deliver high-performance results. With outstanding quantum efficiency across the visible spectrum, these sensors are ideal for demanding imaging applications that can accommodate a mechanical shutter or strobe illumination, such as electronic still photography, medical X-ray, and inspection.
Kodak KAF-16803 Monochrome Sensor Specifications:
- CCD: KAF-16803
- Pixels: 16 Megapixels
- Array: 4096 x 4096
- Pixel: 9 microns
- Monochrome or Color: Monochrome
- Notes: full frame, ABG, micro-lens
Self-Guiding Cover for STX Filter Wheels: This is an attachment for the FW7-STX or FW5-STX filter-wheels designed to turn said products into self-guiding filter wheels. The STX Guider is a simple object that attaches to the front of the FW7 or FW5, modifying them as mentioned. Self-guiding is agreed upon by the vast majority to be the best and most accurate way to guide long exposure astrophotos, most especially so with commercial SCTs. Yet a common complaint plagues self-guiding- the difficulty in finding bright stars when guiding through dark or narrow-band filters. However, the STX Guider remedies this by incorporating a KAI-0340 CCD with 640 x 480 pixels at 7.4 microns, which attaches to the front of the STX Filter Wheel so that the guider picks off light from the intended guide stars before passing through filters. Indeed, you may recognize this guiding CCD as the very same sensor used in the ST-i autoguider. To further augment the effect of this Auto-Guiding conversion, the optical elements that transfer the light from the pick-off mirror to the CCD act as a 0.7x focal reducer. The result? The field of view of the guiding CCD is doubled, resulting in a correspondingly greater selection of guide stars, and remedying one of the main issues of most auto-guiding systems. Also of note are the two smaller adjustment knobs on the STX Guider; one for focus and the other for moving the pick-off-mirror to avoid vignetting. A third and final knob on the side of the unit locks these adjustments into place once your optimal focus is achieved. In addition, a short cable is provided to connect the STX Guider to the remote guide head-port on the camera, and the STX Guider is fully compatible with the AO-X adaptive optics accessory. At the light weight of a single pound, the STX guider is highly portable; and it only consumes 3/4-inch of back focus, requiring absolutely no additional adapters to function.
- Attachment turns filter-wheels into Self Guiding Filter-wheels
- KAI-0340 CCD works to mitigate primary issue of self-guiding filters
- Only consumes 3/4" of back focus
- Requires no additional add-ons
SBIG Seven Position Filter wheel for the STX: The Ultimate Package includes this seven position filter wheel that is sized for 50 mm filters. It integrates perfectly with the Self Guiding cover that was mentioned earlier and is, of course, compatible with the STX 16803 camera. It enables you to freely shift between seven pre-selected filters at your leisure, and with the Self Guiding cover attached it becomes a party to the many benefits listed above!
AO-X Adaptive Optics System: The AO-X is a large aperture Adaptive Optic designed to be compatible with all STX and STXL series cameras, including the STX-16803, STXL-16200, STXL-11000, and STXL-6303. The AO-X requires minimal backfocus while offering a large 3-inch aperture optical element, which is large enough to cover the KAF-16803 CCD sensor.
The AO-X will stack on top of the Filter Wheel and the STX Guider in your setup, working to provide the full benefit of adaptive optics to your imaging pleasure. It provides a definite stabilizing effect to jitters in your image capture.