CCD

[matcat]

I know what a CCD camera is, I need to know what the letters stand for.

 

[zavvy]

Charge Coupled Device....

 

[tfwthom]

From SBIG http://www.sbig.com/sbwhtmls/online.htm<br /><br />Raw CCD images are exceptional but not perfect. Due to the digital nature of the data many of the imperfections can be compensated for or calibrated out of the final image through digital image processing.<br /><br />Composition of a Raw CCD Image.<br /><br />A raw CCD image consists of the following signal components:<br /><br />IMAGE SIGNAL - The signal from the source.Electrons are generated from the actual source photons.<br /><br />BIAS SIGNAL - Initial signal already on the CCD before the exposure is taken. This signal is due to biasing the CCD offset slightly above zero A/D counts (ADU).<br /><br />THERMAL SIGNAL - Signal (Dark Current thermal electrons) due to the thermal activity of the semiconductor. Thermal signal is reduced by cooling of the CCD to low temperature.<br /><br />Sources of Noise<br />CCD images are susceptible to the following sources of noise:<br /><br />PHOTON NOISE - Random fluctuations in the photon signal of the source. The rate at which photons are received is not constant.<br /><br />THERMAL NOISE - Statistical fluctuations in the generation of Thermal signal. The rate at which electrons are produced in the semiconductor substrate due to thermal effects is not constant.<br /><br />READOUT NOISE - Errors in reading the signal; generally dominated by the on-chip amplifier.<br /><br />QUANTIZATION NOISE - Errors introduced in the A/D conversion process.<br /><br />SENSITIVITY VARIATION - Sensitivity variations from photosite to photosite on the CCD detector or across the detector. Modern CCD's are uniform to better than 1% between neighboring photosites and uniform to better than 10% across the entire surface.<br /><br />Noise Corrections<br />REDUCING NOISE - Readout Noise and Quantization Noise are limited by the construction of the CCD camera and can not be improved upon by the user. Thermal Noise, however, can be reduced by cooling o <div class="Discussion_UserSignature"> <font size="1" color="#3366ff">www.siriuslookers.org</font> </div>

 

[nevers]

And I thought it was CAMERA'S that COST DOLLARS!?!?!?!? <img src="/images/icons/wink.gif" />

 

[tfwthom]

I still want to get a CCD cameras. I want to see one of those new Meades but I really want an ST 2000. Got to win big in Vegas in May lol. <div class="Discussion_UserSignature"> <font size="1" color="#3366ff">www.siriuslookers.org</font> </div>