The one trillionth byte saved by the NOAO "Save the Bits" archive was announced in the March 1995 NOAO Newsletter. It took just two and a half years for KPNO (and NSO nighttime) observers to compile that impressive total from "first byte" on 20 July 1993. One year later, however, NOAO observers have already doubled the total.
As of mid-January 1997, the total number of NOAO science images archived is 860,000, for a data volume of 2.03 Terabytes. These images break down as 540,000 program object exposures and 320,000 calibration images. An exact estimate of the total shutter-open exposure time for the half million program object frames is not currently available - due to image header keyword issues that were resolved this year - but this should be significantly in excess of 20,000 hours.
Careful readers have noted the distinction between KPNO and NOAO observers in the first paragraph. Indeed, the big news this year for NOAO archiving is that CTIO data are now being saved from all four CTIO optical/IR imaging telescopes. The other major addition to the NOAO nighttime data stream is, of course, the first full year of WIYN operations.
A summary of the Kitt Peak archive statistics for 1996 is shown in the table below. (The "KPNO" totals include data from the NSO McMath nighttime program.) A detailed breakdown of the CTIO statistics will appear in a later Newsletter after all CTIO telescopes and instruments have reached full archive operation. NOAO observers flirted with archiving a full Terabyte in 1996, but did not quite reach the mark. This milestone should be easily surpassed in 1997.
Telescope Total Object Calib Exposure
No. Mb No. Mb No. Mb Time (hrs)
4-m 41636 71959 28224 32177 13412 39785 1186:27
WIYN 26012 159067 9639 47816 16373 111253 1109:15
2-m 59375 38556 45684 22029 13691 16528 1024:33
Coudé Feed 31029 33417 16447 11709 14582 21708 1355:21
McMath 10374 577 4009 227 6365 350 480:07
0.9-m 22579 135929 13117 72447 9462 63481 900:23
Schmidt 20764 132999 10854 59533 9910 73466 890:03
KPNO 1996 211769 572504 127974 245938 83795 326571 6946:09
NOAO 1996 283512 994145 172363 480175 111149 513972 9236:57
KPNO to date 793353 1614544 497033 752600 296320 861968 N.A.
NOAO to date 865096 2036185 541422 986837 323674 1049369 N.A.
Rob Seaman