Polaroid ST-7E, ST-8E, ST-9E manual 20.6x sizeum Focal length cm

		Section 4 - Camera Hardware
	CCD Used	Number of	Pixel	Array	Read	Full Well
Camera		Pixels	Dims.	Dimension	Noise	Capacity
Tracking	TC-211	192 x 164	13.75 x 16µ	2.6 x 2.6mm	12e- rms	150Ke-
CCD					20e- rms	50Ke-
ST-5C	TC-255	320 x 240	10 x 10µ	3.2 x 2.4mm
ST-237	TC-237	640 x 480	7.4 x 7.4µ	4.7 x 3.6mm	15e- rms	20Ke-
STV	TC-237	320 x 200	14.8 x 14.8	4.7 x 3.0mm	17e- rms	20Ke-
ST-6	TC-241	375 x 242	23 x 27µ	8.8 x 6.6mm	30e- rms	400Ke-
ST-7E	KAF0401E	765 x 510	9 x 9µ	6.9 x 4.6mm	15e- rms	50Ke-/100Ke-4
ST-8E	KAF1602E	1530 x 1020	9 x 9µ	13.8 x 9.2mm	15e- rms	50Ke-/100Ke-4
ST-9E	KAF0261E	512 x 512	20 x 20µ	10.2 x 10.2mm	13e- rms	200Ke-

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 PCs and Macintosh computers offering graphics resolutions of 320 x 200 to 640 x 480 with good grey scale, the CCDs used in the SBIG cameras offer a good trade off between cost and resolution, matching the computer's capabilities well.

Pixel Dimensions - The size of the individual pixels themselves really plays into the user's selection of the system focal length. Smaller pixels and smaller CCDs require shorter focal length telescopes to give the same field of view that larger CCDs have with longer focal length telescopes. Smaller pixels can give images with higher spatial resolution up to a point. When the pixel dimensions (in arcseconds of field of view) get smaller than roughly half the seeing, decreasing the pixel size is essentially throwing away resolution. Another aspect of small pixels is that they have smaller full well capacities.

For your reference, if you want to determine the field of view for a pixel or entire CCD sensor you can use the following formula:

8.12x size (µm)

Field of view (arcseconds) = focal length (inches)

Field of view (arcseconds) =

20.6x size(um)

focal length (cm)

where size is the pixel dimension or CCD dimension in millimeters and the focal

4The Kodak CCDs (KAF0400 and KAF1600) are available with or without Antiblooming Protection. Units with the Antiblooming Protection have one-half the full well capacity of the units without it.

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