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Choosing a CCD camera for astrophotography

Choosing a CCD camera for astrophotography

by eng.izajJanuary 16, 2018

Choosing a CCD camera for astrophotography is’t not a big deal. you just need to know few things such as what is you budget, size of camera, field of view, Sensitivity, resolution, cooling and dark current noise, guiding and which software are you use etc. So let’s start learning baseline of  Choosing a CCD camera for astrophotography.

What is CCD Camera?

Best Ans from Wikipedia: A charge-coupled device (CCD) is a device for the movement of electrical charge, usually from within the device to an area where the charge can be manipulated, for example conversion into a digital value. This is achieved by “shifting” the signals between stages within the device one at a time. CCDs move charge between capacitive bins in the device, with the shift allowing for the transfer of charge between bins.

Types of CCD Camera?

Camera Expertise divide Four types of CCD Camera Liner, Interline, Full-Frame and finally Frame-Transfer

Liner: Linear CCD consists of a single row of pixels–all in one line. To define an image, a Linear CCD must be scanned across the plane of the image, building the picture row by row. It is, obviously, a much slower process than using a sensor that captures the entire image simultaneously. And, it requires the use of stepper motors, which increases the complexity of the system, the potential for mechanical misalignment and breakdown, and greater noise.

Interline:  Interline CCD, each pixel has both a photodetector and a charge storage area. The storage area is formed by shielding or masking part of the pixel from light and using it only for the charge transfer process. The masked areas for each pixel form a vertical charge transfer channel that runs from the top of the array to the horizontal shift register.

Full-Frame: Full-Frame CCDs devote the entire pixel to image capture. Therefore, when the charge transfer occurs, the pixel is busy and cannot continue to capture photons. To keep the pixels from continuing to read additional light when they are involved in charge transfer (which can lead to light smear on the image), digital camera designers usually put a mechanical shutter between or behind the camera lens.

Frame-Transfer: Frame-Transfer CCDs are similar to Full-Frame, but they mask out half of the array to provide temporary storage for the electric charges, aptly called the “storage array”. Once an integration period ends and the photosensitive pixels have acquired their charges, they are quickly transferred to the storage array, and can operate without shutter delay. This makes them very fast capture devices.

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