Polaroid ST-8E, ST-9E, ST-7E manual Glossary

Section 8 - Glossary

can be changed. Subsequent downloads will be of the area inside the box resulting in a much faster update rate.

Quantum Efficiency - Quantum Efficiency refers to the fractional number of electrons formed in the CCD pixel for a given number of photons. Quantum Efficiency is usually plotted as a function of wavelength.

Readout Noise - Readout noise is associated with errors generated by the actual interrogation and readout of each of the CCD pixels at the end of an exposure. This is the result of fixed pattern noise in the CCD, residual charge in the readout capacitors and to a small extent the noise from the A/D converter and preamplifier.

Resolution Mode - The resolution of a CCD camera is determined by pixel size. Pixel size can be increased by combining or binning more than one pixel and displaying it as one pixel. Doing so decreases the effective resolution but speeds up the download time of the image. Maximum resolution is determined by the size of the individual CCD pixel. The ST-7E/8E/9E can run in High, Medium, Low and Auto resolution modes.

Response Factor - Response Factor is a multiplier used by CCDOPS to calibrate CCDOPS to a given telescope for photometric calculations. The Response Factor multiplied by 6700 is the number of photoelectrons generated in the CCD for a 0th magnitude star per second per square inch of aperture.

Saturation - Saturation refers to the full well capacity of a CCD pixel as well as the maximum counts available in the A/D converter. The pixel is saturated when the number of electrons accumulated in the pixel reaches its full well capacity. The A/D is saturated when the input voltage exceeds the maximum. The saturation values for the various cameras are shown in the table below.

	Full Well	Maximum	e-/Count7
Camera	Capacity	A/D Counts
ST-5C	50,000e-	65,535	1.25
ST-237	20,000e-	4,095	3.4
ST-6	400,000e-	65,535	6.7
ST-7E/ST-8E8	50,000e-	20,000	2.3
High Res	160,000e-
ST-7E/ST-8E		65,535	2.3
Med/Low Res	150,000e-
ST-7E/8E/9E		65,535	1.3
Tracking CCD	200, 000e-
ST-9E		65,535	2.8

Sky Background - The sky background illumination or brightness is the number of counts in the image in areas free of stars or nebulosity and is due to city lights and sky glow.

7

8

The e-/Count shown are for the High Resolution readout mode. These numbers can be different for other readout modes. Use the Parameters command in the Display menu to see the actual value for images acquired in other readout modes.

The Non-ABG versions of the ST-7E and ST-8E have twice the full-well capacity of these values shown.

Page 49