The Construction of a Multi CCD Camera
Abstract
Sky surveillance projects require the largest possible sky coverage. Doing so with a given image sampling (number of arc seconds per pixels) and a given telescope require the largest possible detector. There are three ways of installing large charge coupled device (CCD) detectors at the focus of a telescope: (1) use a single intrinsically large detector; (2) build a large CCD matrix using buttable devices; or (3) build a multi-CCD camera, provided the field of view of the telescope is large enough. The final solution is the one on which the authors have worked for the last 2 years, i.e. placing several individual CCDs in a large focal plane to recreate a single continuous image using multiple exposures. With the Sloan Digital Sky Survey project, which used 30 2K devices in great circle scanning, 2 exposures were required to produce a continuous image of the sky. In this case, taking into account the specificity of the telescope (a 30x30 cm curved field of view), the authors thought that using 9 2K CCDs to create a pseudo array 5 degrees high would be the most cost-effective solution. The general arrangement of this array has been described elsewhere (the OCA CCD controller). The development of the multi-CCD controller took more time than expected, as did the development of the required detection software. When an initial system started to work, regular observations started to take a substantial part of the authors' time. Nevertheless, between the time this contract was awarded and today, several projects were undertaken to further the construction of such a multi-CCD camera. While it is likely that the authors are going to replace their current 2K device with a larger 4K device or a 7Kx9K one, they believe the technology development they did around this idea was valuable. It is noted that a single 7Kx9K device covers almost the area of 10 2K CCDs, and both its installation and use at the telescope is easier than using 9 individual chips. (11 figures)
Document Details
- Document Type
- Technical Report
- Publication Date
- Jan 01, 1996
- Accession Number
- ADA411575
Entities
People
- Alain Maury