Specifications

Section 4 – Camera Hardware
Page 47
How these features affect the average user are discussed in the paragraphs below:
A/D Resolution - This is a rough indication of the camera's dynamic range. Higher precision
A/D Converters are able to more finely resolve differences in light levels, or for
larger CCDs with greater full well capacities, they are able to handle larger total
charges with the same resolution.
Temperature Regulation - In an open loop system like the original ST-4 the CCD cooling is
either turned on or turned off. While this provides for adequate cooling of the
CCD, the CCD's temperature is not regulated which makes it important to take
dark frames in close proximity to the associated light frame. Closed loop
systems regulate the CCD's temperature to an accuracy of ±0.1° C making dark
frames useful over longer periods.
Electromechanical Shutter - Having the shutter in the Research Series cameras gives streak-free
readout and allows taking dark frames without having to cover the telescope.
While the minimum exposure is 0.11 seconds, repeatability and area uniformity
are excellent with SBIG's unique unidirectional shutter.
Filter Wheel - The internal Filter Wheel allows you to take color images or separate UBVRI for
photometric measurements automatically.
Electronic Shutter - Having an electronic shutter involves having a CCD with a frame transfer
or interline region. In frame transfer or interline CCDs at the end of the
exposure, the pixel data from the Image Area is transferred into the Storage Area
very rapidly where it can be read out with a minimum of streaking.
In addition to the system level differences between the various cameras, Table 4.3 below
quantifies the differences between different CCDs used in the cameras:
Camera CCD Used Number of
Pixels
Pixel
Dimensions
Array
Dimension
Read
Noise
Full Well
Capacity
TC237 Tracking CCD TC-237 657 x 495 7.4 x 7.4 µ 4.9 x 3.7 mm 15e- rms 20Ke-
STL-4020M KAI-4020M 2048 x 2048 7.4 x 7.4 µ 15.2 x 15.2 mm
15e
-
rms 40Ke
-
STL-1301E KAF-1301E 1280 x 1024 16 x 16 µ 20.5 x 16.4 mm
15e
-
rms 120Ke
-
STL-1001E KAF-1001E 1024 x 1024 24 x 24 µ 24.6 x 24.6 mm
15e
-
rms
200Ke-
STL-6303E KAF-6303E 3072 x 2048 9 x 9 µ 27.6 x 18.4 mm 15e- rms
100Ke
-3
STL-11000M KAI-11000M 4008 x 2745 9 x 9 µ 36.1 x 24.7 mm 12e- rms 50Ke
Table 4.3- CCD Differences
How these various specifications affect the average user is described in the following
paragraphs:
Number of Pixels - The number of pixels in the CCD affects the resolution of the final images.
The highest resolution device is best but it does not come without cost. Larger
CCDs cost more money and drive the system costs up. They are harder to cool,
require more memory to store images, take longer to readout, etc. With typical
3
Some Kodak CCDs (KAF1301E and KAF6303E) are available with or without Antiblooming
Protection. Units with the Antiblooming Protection have one-half the full well capacity of the units
without it.