Date: Mon, 29 Sep 2003 15:45:40 -1000 From: Douglas Toomey To: denault@jeans.ifa.hawaii.edu, techgroup@jeans.ifa.hawaii.edu, Jim or Pat Harwood , irwin@galileo.ifa.hawaii.edu Subject: Re: TCS3 Requirements Meeting. Comments on the requirements document 1) section 1.5 Offsetting and Scanning Accuracy of <= 1 arc sec for offset less that 1 degree we should be able to offset with an accuracy much better than 1 arcsecond for small offsets. I would think that for offsets around 80 arcseconds or less we would want around 0.1 arcseconds accuracy. 2) there are no comments related to safety. Does this document represent all of the requirements or are there other documents as well. I would expect a safety document but there should be one requirements document that brings it all together. For example I expected to see a requirement like " the system must be designed such that the telescope cannot run away. The sensors that detect this condition must be redundant in nature so that a single sensor failure would still not allow the system to run away." My opinion is that the safety to people and hardware issues should generate requirements for the system that should be represented in this document. You do have some safety related software items at the end but I think the requirements should be stated in a more global sense as above. 3) Sky coverage - there are observing coverage limits and also maintenance coverage limits are there not?