Date: Tuesday 30 Sep 2008 03:42:16 PM PDT Subject: Important notes regarding preparation of Spitzer Cycle-6 proposals For those of you currently preparing proposals for the Spitzer Cycle-6 Exploration Science General Observer program deadline on October 10, we are providing in this email some important notes that you should know before submitting the final version of your proposal. 1) In the Call for Proposals and the Spitzer Observer Manual (SOM) we have indicated that the maximum duration of IRAC AORs in Cycle-6 will be 24 hours. If you have attempted to create an AOR with a duration greater than 8 hours with the IRAC Post-Cryo Mapping AOT, you may have already noticed that you still are receiving a warning that you have exceeded the 8-hour limit (the limit for Cycle-5 IRAC AORs) and are unable to obtain an accurate resource estimate for that AOR. We are modifying the maximum duration from 8 hours to 24 hours in our database. However, that modification will not have been accomplished in time for the upcoming proposal deadline. What we recommend you do, instead, is to create n AORs, which correspond to the equivalent time greater than 8 hours that you desire for one AOR, and chain these n AORs together (ignore the warning that you will obtain, saying that you have exceeded the 8-hour limit on chains), and then subtract [n - 1] * 215 seconds from the total duration of this AOR chain (subtract [n - 1] * 515 seconds for AORs observing moving targets), to estimate the total time for the equivalent 8-hour AOR. 2) You are reminded that the increase to a 24-hour maximum duration for the IRAC Post-Cryo Mapping AOT for Cycle-6 is primarily intended for staring observations at a single target (e.g., observing an exoplanet transit). Most observations involving mapping will actually be limited first by the number of spacecraft commands allowed for a single AOR. If you exceed the command limit, Spot will give you an error message. For AOT frame times of 12 seconds or less, the practical AOR duration for mapping is, therefore, about 5 hours or less (the equivalent of about 630 individual dither positions). Maps of >8-hour durations will also be possible. For the moment, please break the larger map into 8-hour chained segments. Please also note that single (or chained) requests that are a significant fraction of a nominal period between downlinks (approximately 22 to 24 hours) will be more difficult to schedule. 3) The 200- and 400-second frame times have not yet been characterized. This will happen during the instrument characterization period immediately prior to the commencement of Cycle-6 science observations. The SSC is reasonably confident that the 200-second frame time will prove useful, but the 400-second frame time is more of a contigency. For the purposes of proposal preparation, you should use frame times 200 seconds or less to achieve the equivalent integration time. If the 400-second frame time has been proven effective, observers with approved Cycle-6 proposals will be allowed to modify their AORs using these longer frame times. This will inevitably mean that the observing efficiency will improve slightly, and observations will be deeper (or wider). In the event that the 200-second frame time proves less useful, observers may be asked to replan using the 100-second frame time. The Cycle-6 Call for Proposals and other information regarding the Call are available at http://ssc.spitzer.caltech.edu/propkit/currentcp.html. A reminder that the Cycle-6 Exploration Science proposal deadline is Friday, 2008 October 10, 5 PM Pacific Daylight Time. If you have any questions regarding these points above and observation planning, in general, for Cycle-6, please do not hesitate to contact us at the Helpdesk, help@spitzer.caltech.edu. Spitzer Science User Support