Pipeline 3 processing will employ darks compiled from long-period
runs of nightly darks of similar electronic response. As a first step in
this analysis, the darks history has been studied to see at which dates
the darks structure has changed significantly. Images of
Northern and Southern canonical
averages are collected separately.
Read1 Darks are not presented on this graph but largely followed the behavior of the read2 darks. However, one additional hardware break was warranted after 980411n, and several bands that showed no change in read2 at a break did show jumps at read1 (and were therefore broken at that date). Overall, any significant change in behavior of the darks in either read1 or read2 was considered sufficient to break the running average for that band.
A summary of these breaks and associated events in the log file
is given below.
a 970000 970830 JHK summer shutdown b 970901 971114 JHK work during rain at telescope for several days c 971115 971224 J holiday shutdown d 971225 980411 JH zener diodes added (read1 changes) e 980412 980719 JHK summer shutdown f 980720 980924 JHK Leach test at start of night g 980925 981014 H camera pumped down (only 3 days of darks; no break) h 981015 981022 H Leach replaces GATIR electronics i 981023 981118 J K Leach eprom change (actually before obs on 18th??) j 981119 990427 JH Leach software upgrade k 990428 990612 JH slight warmup of camera l 990613 990720 J K summer shutdown m 990721 991202 JHK H banding problems show in darks? n 991203 000322 H camera pumped down o 000323 000724 K summer shutdown p 000725 020101 JHK end of ops
The three dates on which darks show significant changes are summarized
below (notes refer to event marking end of hardware period).
970000 990117 JHK electronics maintenance 990116 990226 JHK Leach installed 990227 990506 JHK Leach eprom upgrade 990507 020000 JHK end of survey