From help@spitzer.caltech.edu Fri Dec 19 16:04:28 2003 Date: Fri, 19 Dec 2003 15:54:14 -0800 (PST) From: Spitzer Science Center HelpDesk Reply-To: sirtf-astro@ipac.caltech.edu To: sirtf-astro@ipac.caltech.edu Cc: help@spitzer.caltech.edu Subject: SIRTF: Spitzer Space Telescope Document update and Call for Proposals +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ You are subscribed to sirtf-astro. To unsubscribe please send an email to majordomo@ipac.caltech.edu with "unsubscribe sirtf-astro " where your_email@address is the email address at which you receive this mailing. +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Contents of mailing: 1) Announcement of Spitzer Space Telescope Document Updates +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ The Spitzer Science Center (SSC) is pleased to announce the opening of the General Observer Cycle 1 Call for Proposals. The deadline for the GO1 Call is Saturday February 14, 2004 at 12:00 (Noon) PST. The Spitzer's Observer Manual (SOM) has been revised to include updates from on-orbit performance of the spacecraft and the science instruments. In some cases the on-orbit performance is still being evaluated. The SSC will post any additional updates to science instrument performance on our web pages on or before January 15, 2004 to support the GO1 Call. Some important URLs: SSC Home Page: http://ssc.spitzer.caltech.edu GO1 Call Documents: http://ssc.spitzer.caltech.edu/propkit/currentcp.html Spitzer Observer's Manual: http://ssc.spitzer.caltech.edu/documents/som/ Spitzer Reserved Observations Catalog (ROC): http://ssc.spitzer.caltech.edu/roc/ A new release of SPOT, the Spitzer Planning Observations Tool, is anticipated on December 30, 2003. If you have any questions contact us at the Spitzer Science Center Helpdesk at help@spitzer.caltech.edu Some of the highlights of on-orbit performance of the Spitzer Space Telescope and the science instruments are: Spacecraft ---------- - As commanded pointing accuracy < 1 arcseconds (1 sigma radial) - Diffraction limited at 5.5 microns - Estimated lifetime of ~ 5 years (reference: SOM V4, Section 2.3, page 7) Observing with Spitzer ---------------------- Currently, the commissioned observing modes for Spitzer are: - IRAC Mapping - IRS Stare - IRS Spectral Mapping - MIPS Photometry/Super-Resolution - MIPS Scan Maps These observing modes will be commissioned at a later date: - MIPS Spectral Energy Distribution (can be applied for in GO1 Call) - MIPS Total Power Mode (will be available for GO2 Call) IRAC (Infrared Array Camera) ---------------------------- - All four detector arrays are performing well. - The point source sensitivity of the four IRAC bands (200 seconds, 1 sigma, low background) are: 0.40, 0.84, 5.5, and 6.9 microJy at 3.6, 4.5, 5.8, and 8.0 microns, respectively. (SOM V4, Section 6.2.1, page 97) The ratios of on-orbit to pre-launch point source detection thresholds are 0.69, 0.75, 1.60, and 1.31 for 3.6, 4.5, 5.8, and 8.0 microns, respectively. - Several instrumental artifacts one should be aware of: - persistent images in 3.6 micron and 8.0 micron arrays (SOM V4, Sections 6.1.3.2.2 - 6.1.3.2.3, page 79) - point source and diffuse stray light (SOM V4, Section 6.1.2.2.2, page 72) - muxbleed, banding, and column pulldown => For full details, observers should read the IRAC chapter of the SOM. Many of the instrumental artifacts can be eliminated or significantly reduced by performing well-dithered observations. We continue to recommend covering every part of your science target with at least three images. IRS (Infrared Spectrograph) --------------------------- - All four spectrograph modules and the IRS peak-up arrays are performing well. All IRS arrays are more sensitive than pre-launch estimates. (SOM V4, Section 7.2.1.2, page 152, and Section 7.2.1.2.1, page 156) - Slit and peak-up field-of-view dimensions, as well as wavelength ranges that can be calibrated for each (sub-)slit, have been changed slightly to reflect in-orbit measurements. (SOM V4, Section 7.1.1, page 130, and Section 7.1.2, page 133) - The pointing accuracy of Spitzer is very good. Low accuracy IRS peak-ups may not be necessary if target coordinates are well known, or if peak-up images are not required. (SOM V4, Section 7.2.3.1.3, page 162) => For full details, observers should read the IRS chapter of the SOM. MIPS (Multiband-Imaging Spectrograph for Spitzer) --------------------------------------------- - The 24 micron array is performing well. - The point source sensitivity of the 24 micron array is about 110 microJy (500 seconds, 5 sigma, dark sky) or about 1.5 times deeper than pre-launch predictions. The saturation limit is estimated to be 4.1 Jy, lower than pre-launch predictions. (SOM V4, Section 8.2.2.4, page 275) - One side of the 70 micron array suffers from fixed pattern noise due to a thermally activated high resistance in a cable connection external to the instrument. It also affects one block of pixels on the good side of the array. (SOM V4, Section 8.1.2.2, page 217) - The sensitivity of the 'good' side of the 70 micron array is about 6 mJy in 500 seconds (5 sigma, no confusion), about 3 times worse than pre- launch predictions. The sensitivity of the 'bad' side of the array is a factor of 2-3 worse than the good side. Sensitivity estimates for 70 microns are still being refined. Check the SSC web pages for updates on or before January 15, 2004. - The sensitivity of the 160 micron array is still being refined. We will post sensitivity information on our web pages at it becomes available. Check the SSC web pages on or before January 15, 2004. - The 160 micron array is performing well except one block of 5 pixels does not operate properly. (SOM V4, Section 8.1.2.2, page 217) - The 160 micron array has a 1.0 - 1.6 micron spectral leak. (SOM V4, Section 8.1.2.4.3, page 219, Section 8.1.3.5.9, page 235) => For full details, observers should read the MIPS chapter of the SOM. The Photometry/Super-Resolution AOT has been optimized for the 'good' sides of the 70 and 160 micron arrays. The Scan AOT now has a few more smaller cross-scan step sizes to optimize observations for good overlap of 70 or 160 micron data. SSC Observer Support Team