Polaroid ST-7E, ST-8E, ST-9E manual At the Telescope with a CCD Camera

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Section 3 - At the Telescope with a CCD Camera

Color imaging places some interesting requirements on the user that bear mentioning. First, many color filters have strong leaks in the infrared (IR) region of the spectrum, a region where CCDs have relatively good response. If the IR light is not filtered out then combining the three images into a color image can give erroneous results. If your Blue filter has a strong IR leak (quite common) then your color images will look Blue. For this reason, SBIG incorporates an IR blocking filter stack with the three color band filters.

Second, since you have narrowed the CCD's wavelength response with the interference filters, longer exposures are required to achieve a similar signal to noise compared to what one would get in a monochrome image with wide spectral response. This is added to the fact that tri-color images require a higher signal to noise overall to produce pleasing images. With black and white images your eye is capable of pulling large area detail out of random noise quite well, whereas with color images your eye seems to get distracted by the color variations in the noisy areas of the image. The moral of the story is that while you can achieve stunning results with CCD color images, it is quite a bit more work.

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Contents Operating Manual Page Table of Contents Technique Quick Tour IntroductionRoad Map of the Documentation Ccdops Software Ccdops for Windows or MacintoshCCD Camera Page How CCD Detectors Work Introduction to CCD CamerasCameras in General Full Frame and Frame Transfer CCDs Camera Hardware ArchitectureCCD System Block Diagram CCD Special Requirements CoolingDouble Correlated Sampling Readout Dark FramesFlat Field Images Pixels vs. Film GrainsGuiding Electronic Imaging Black and White vs. Color Page Attaching the Camera to the Telescope At the Telescope with a CCD CameraStep by Step with a CCD Camera Focusing the CCD Camera Establishing a Communications LinkCamera Back Focus Displaying the Image Finding and Centering the ObjectTaking an Image Processing the ImageSub-Frame Readout in Focus Crosshairs Mode Photometry and AstrometryAdvanced Capabilities Track and Accumulate Autoguiding and Self GuidingAuto Grab Color ImagingAt the Telescope with a CCD Camera Connecting the Relay Port to the Telescope Connecting the PowerConnecting to the Computer Camera HardwareUsing Mechanical Relays Push to Make Switch Modification Modular Family of CCD Cameras Joystick ModificationSystem Features 20.6x sizeum Focal length cm Camera Hardware Connecting the older model CFW-6 filter wheel to the Camera Battery Operation Page Deep Sky Imaging Advanced Imaging TechniquesLunar and Planetary Imaging Terrestrial ImagingBuilding a Library of Dark Frames Changing the Camera ResolutionTaking a Good Flat Field Flat Fielding Track and Accumulate Images Tracking Functions Advanced Imaging Techniques Page Accessories for your CCD Camera Cooling BoosterFocal Reducers Tri-color ImagingCamera Lens Adapters and Eyepiece Projection AO-7 and Lucy-Richardson SoftwareWindows Software Third Party Products and ServicesSGS Self-Guided Spectrograph Image Processing SoftwareSbig Technical Support Common Problems Common Problems Common Problems Page Glossary STV Glossary Glossary Sbig Tracking Interface Cable TIC-78 Appendix a Connector ad CablesAppendix a Connector Pinouts Figure A1 CCD Connector for TIC Mating Regenerating the Desiccant Appendix C MaintenanceCleaning the CCD and the Window Page Appendix C Capturing a Good Flat Field TechniquePage Index IBM PC Separations