LSST Commissioning Camera¶

Citation: SLAC National Accelerator Laboratory and NSF-DOE Vera C. Rubin Observatory (2024); LSST Commissioning Camera https://doi.org/10.71929/rubin/2561361

The LSST Commissioning Camera, LSSTComCam (lsstcomcam.lsst.io), is a smaller, fully functional version of LSSTCam. LSSTComCam is also referred to as the engineering test camera.

Focal plane¶

LSSTComCam consists of only a single “raft” of 9 CCDs (charge-coupled device, also called a sensor, detector, or chip). Each CCD is 4k x 4k pixels (4000 by 4000 pixels), for a total of 144 Mpix. For comparison, LSSTCam has 21 rafts, and 189 of the same CCDs. All of LSSTComCam’s CCDs are from ITL, one of the same two vendors that supplied the LSSTCam detectors (ITL and e2v).

A visual showing the relative size of the LSST Commmissioning Camera, with just 9 detectors, compared to the LSST Camera with 189 detectors. — Figure 1: The LSSTComCam has only 9 CCDs compared to LSSTCam’s 189 CCDs.¶

Filters¶

LSSTComCam uses the same ugrizy filters as LSSTCam. LSSTComCam’s filter exchanger can only hold three physical filters at a time (compared to 5 for LSSTCam).

Key numbers¶

CCDs: 9
pixels: 144 Mpix
platescale: 0.2 arcsec / pixel
field of view: 40 x 40 arcminutes
read noise: 6.21 electrons (ITL sensors)
gain: 1.68 electrons / ADU (ITL sensors)

Visit Rubin Observatory’s Key Numbers page, and the page for LSSTCam, for more key numbers.

Known issues¶

LSSTComCam was the instrument used to facilitate early system integration for the Rubin Observatory. It was not, itself, commissioned. The image quality achieved during the LSSTComCam on-sky campaign, and of the data in DP1, is not necessarily indicative of the image quality that Rubin Observatory expects to achieve with LSSTCam.