More Information  · Images of Some Features

The ST-9XEI is the single sensor imaging camera only, with no internal guiding CCD. However, it does include a remote guiding head port for connecting an optional CCD camera to use as a guider, or an external guiding head such as the SBIG #RGH. In addition, the ST-9XEI may be upgraded to a dual-detector self-guiding camera at any time by returning the camera to SBIG and having them install the SBIG TC-237H tracking CCD. This single sensor ST-9XEI is an ideal way to get started with a professional quality CCD camera at a reasonable price, or for anyone who may already have a guiding solution such as the STV or another CCD camera.

The ST-9XEI is an excellent TDI imager. TDI (Time Delay Integration, or “Drift Scan” imaging) is particularly interesting because you can image large areas of the sky without guiding, so any telescope will do. Professional astronomers performing sky surveys or asteroid searches often build instruments that employ TDI with a CCD. This powerful imaging technique not only gives good results, but it can be done with a very simple telescope system. Basically, you point the camera at an area of sky and turn off the telescope drive to let the stars drift across the field of view of the unmoving telescope. As the stars drift across the CCD sensor, the CCD is clocked at exactly the right rate 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 sensor. Depending on the focal length of the telescope, 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 512 x 1000 pixels in size, or 512 x 2000, 512 x 3000, etc. The ST-9XEI’s large pixels make it quite sensitive to extended objects and very good wide field astro images can be created with no telescope tracking at all using the TDI method.

The imaging sensor is a Kodak KAF-0261E CCD with a 512 x 512 array of large 20 micron pixels. This is a Class 1 “E” CCD imaging sensor with high quantum efficiency (QE) and no column defects. The area of the array is about 80% the size of the more expensive ST-8XE and 330% the size of the array used in the ST-7XME. Anti-blooming is not available, and is essentially not needed, as each pixel’s very large full well capacity makes blooming unlikely.

When the ST-9E camera was introduced, the first users’ image SBIG received was from two amateurs, Gary Hug and Graham Bell, who discovered a ~19th magnitude comet: Comet P/1999 X1 Hug-Bell. At that time, with a single exception, it was the faintest comet ever discovered by an amateur astronomer. Gary and Graham were using a 12” SCT at f/6.3. The discovery was made while blinking 6 minute exposures taken in search of an asteroid. Subsequent 10 minute and 20 minute exposures revealed the comet’s tail. Recently SBIG was informed that UK amateur, Mark Armstrong, has discovered no less than 40 supernova using three ST-9E cameras!

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 1 chip of the ST-9XEI has no more than 10 point defects in its imaging area; no more than 4 cluster defects; and no column defects. The few possible point and cluster defects of the ST-9XEI are easily removed from an image during processing.

Pixel binning modes (1x1, 2x2, 3x3) allow the user to match the pixel size to various telescope focal lengths. The camera includes a mechanical shutter, 16-bit analog to digital (A/D) converter, regulated temperature control, and has all of its electronics integrated into the CCD head. No separate CPU is required. Communication to your PC is through new high speed analog and digital 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 less than one second.

The standard cooling configuration is a single stage thermoelectric cooler with an active fan and a newly designed heat exchanger. An optional water-cooling heat exchanger is available that includes an inlet and outlet for water circulation should the user desire to maximize the cooling performance for hot climates. Typical air cooling without water assist is -35° C from ambient. 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 for use with the optional water-cooling heat exchanger.

In addition to the remote guide head port for using an external guiding head or CCD camera, 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, and a relay adapter box for telescopes that do not have a dedicated CCD guider input.

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 with a 15-foot USB cable (commonly available and relatively inexpensive third party USB extenders are available for cable runs up to several hundred feet, something not presently possible with a USB 2.0 interface); 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 T-thread ring for attaching to T-mount photo accessories; a 1/4”-20 thread side plate for tripod mounting; and a universal 90-240VAC power supply with a remote on/off switch.

A supplied CD-ROM has sample images and software for SBIG’s CCDOPS version 5 camera control software, and Software Bisque’s CCDSoft Version 5 image processing/camera control software and TheSky version 5, level II, with telescope control for Windows. You also get an operating manual. An optional custom-designed Pelican hard carrying case with pre-cut foam is available.

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:

Detector: Kodak KAF-0261E high QE Class 1, with no column defects.
Pixel Array: 512 x 512 pixels.
Pixel Size: 20 x 20 microns.
Total Pixels: 262,000.
Full Well Capacity: ~150,000e-.
Dark Current: 4e-/pixel/second at 0 degrees C.

Readout specifications are as follows:

Shutter: electromechanical.
Exposure: 0.12 to 3600 seconds, 10ms resolution.
Correlated Double Sampling: yes.
A/D conversion: 16 bits.
A/D gain: 1.6e-/ADU.
Read noise: 15e- RMS.
Binning modes: 1x1, 2x2, 3x3.
Pixel digitization rate: up to 420,000 pixels per second.
Full frame download: <1 second.

Optical specifications with 8” f/10 (2000mm focal length) scope are as follows:

Field of view: 16.8 x 16.8 arc minutes.
Pixel size: 1.97 x 1.97 arc seconds.

System specifications are as follows:

Standard cooling: single stage thermoelectric, active fan, water assist ready, -35° C from ambient typical, air cooling only (-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 amps, power supply included.
Computer interface: USB 1.1.
Computer compatibility: Windows 98/2000/Me/XP.
Guiding: patented dual CCD self-guiding.

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 pounds/0.9 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.