20 March 1997

HRC-I was turned on at about 6pm (3/19/97 CST) and the High Voltage slowly raised to the operating point over two hours. The MCP background rate is remarkably low - 2.6 cts/sec over then entire image (1 ct arcsec-2 fortnight-1)! This is almost twice as low as we saw in Cambridge and we think it is due to the excellent vacuum at XRCF and the large distance of the HRC from any naturally occurring radiation. We are extremely happy with this performance. There are no hot spots or warm spots in a 3600 second background test, another encouraging result.

At about midnight CST the HRC saw first light from the HRMA! The image was a 25 mm out of focus run with one quadrant shutter closed on shells 3 and 4 (different quadrants). This was a low flux run lasting 500 seconds. The quick look (undegapped0 image is being placed in pool space as soon as we can set up to make the transfer! From this image we were able to immediately determine that the HRC is in front of the focus by 25-27mm (better values will come later), and that we understand the sense of the facility coordinate system relative to the HRC. We all breathed a sigh of relief and after a very brief celebration got down to the real work of HRC calibration.