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 Chandra Electronic Bulletin No. 47 ******************************************************************************** | | | CCC XX XX OOO | Chandra | CC XX XX OO OO | CXC Electronic | CC XXX OO OO | Number 47 Bulletin | CC XX XX OO OO | February | CCC XX XX OOO | 2006 | | ******************************************************************************** Welcome to the Chandra X-ray Center's Electronic News Bulletin Number 47. CXC Web site: http://cxc.harvard.edu If you would like to unsubscribe from this alias, simply reply to this message to let us know. Please use this website to update your address or email: http://cxc.harvard.edu/cdo/udb/userdat.html Contents: 1. Update to Procedure for Charging Slew Tax on Raster Surveys in Cycle 8 ------------------------------------------------------------------------------- Item 1. Update to Procedure for Charging Slew Tax on Raster Surveys in Cycle 8 ======================================================================== The following text has been included as an erratum to the Cycle 8 Call for Proposals, and can also be found on the website under "CfP Errata" http://cxc.harvard.edu/proposer/CfP/cfp_errata.html Section 7.1 is updated as follows: An observing efficiency including slew and settle time will be used to determine the amount of time available for observations. To evaluate time required by a given proposal, a "slew tax" of 1.5 ksec will be added to each proposed target within the peer review process; this added time closely represents the average observatory slew and set-up time required for each observation. The Peer Review takes the slew tax into account along with the requested time when assessing the resources requested to accomplish a proposed research project. For a large set of short exposures this slew tax can substantially increase the "cost" in terms of time needed for a project. Starting with Cycle 8, this policy is modified as follows: For a series of contiguous or nearly contiguous pointings (maneuver from one observation to the next of less than or equal to 1 degree), with no change in instrument set-up or observing mode, the slew tax for the first observation will remain 1.5ksec, while for observations 2 through n (where "n" is explained below) will be assessed at 0.5ksec. The series of pointings will be assembled into one or more groups comprised of a set of closely spaced pointings with maximum exposure time per group of 30 ksecs, including the slew tax. The value of "n" is the number of observations which can be done including the slew tax without exceeding 30 ksecs. Thus proposals requesting more time than 30 ksecs (including slew tax) will be assessed slew tax in several groups, the first observation of which will be charged 1.5ksec slew tax. Proposers should set the RPS flag {\it Is this target part of a raster survey?"} to be "Y" (yes). The formula for slew tax is included here to enable proposers to understand the total time which they are effectively requesting; however the time on target is all that the proposers should include in their proposal. The CXC will compute the slew tax and provide the information to the Peer Review. Please note that observations taken as part of a raster survey are not constrained and therefore are not guarenteed to have the same (or similar) roll angle. Proposers must also include a group or roll constraint if they wish to ensure the individual observations have roll angles within particlar tolerances. ------------------------------------------------------------------------------- This Electronic Bulletin is used for the dissemination of important announcements and information about the Chandra X-Ray Observatory to members of the community. If you wish to unsubscribe from the list, simply reply to this email to let us know.