Data Set Overview : This data set contains raw spectral images of Comet 9P/Tempel 1 obtained with SpeX, the low- to medium-resolution near-IR spectrograph and imager at the NASA Infrared Telescope Facility (IRTF) on Mauna Kea, Hawaii. In addition to the spectral images of Tempel 1, numerous flat field and Argon lamp images are included that are required to process the comet data.  The SpeX instrument is fully described in papers by Rayner et al. (2003,2004) [RAYNERETAL2003, RAYNERETAL2004]. For the Comet 9P/Tempel 1 observations, a number of slit and prism / grating combinations were used, producing spectra with resolving powers ranging from 100 to 1500, and covering the two spectral regions from 0.8 to 2.5 microns and from 2 to 5.5 microns. The lowest resolution spectra, taken in the LowRes Prism mode, cover the wavelength interval from 0.8 to 2.5 microns in a single, continuous spectrum. The higher resolution modes SXD (covering the interval 0.8 to 2.5 microns), LXD 1.9 (1.9 - 4.2 microns), LXD 2.1 (2.1 to 5.0 microns) and LXD 2.3 (2.3 - 5.5 microns) use gratings and prism cross-dispersers to separate overlapping spectral orders. In these higher-resolution modes, there is sufficient wavelength overlap between adjacent orders to produce spectra with continuous coverage over the entire interval from 0.8 to 5.5 microns. Diagrams showing the spectral position on the array for LowRes Prism (LRes15_spec_layout.jpg), SXD (SXD_spec_layout.jpg), LXD1.9 (LXD19_spec_layout.jpg) and LXD2.3 (LXD23_spec_layout.jpg) modes are provided in the documents directory.  The spectrograph utilizes a 1024x1024 Aladdin 3 InSb array. The spatial (along-slit) image scale for all of the slit / grating combinations of the spectrograph is 0.15 arcsec / pixel. The gain is fixed at 13.0 electrons / ADU. The array is linear to about 5 percent up to 4000 DN per read. Each fits image contains the sum of all non-destructive reads and coadds acquired during the exposure, and thus will normally contain count levels much higher than 4000 DN. To obtain the average counts per read, a normalization value is provided in the image header (keyword : DIVISOR) that is the product of the non-destructive reads and coadds.  Observations were typically obtained as A - B nodded pairs, in which the telescope position was shifted about 7.5 arcsec along the direction of the 15-arcsec long slit, producing an offset in the target spectrum between the A- and B-beam images. These image pairs allow for mutual sky subtraction between the A - B and B - A image combinations. The beam position for each image is integrated into the fits file name, with the extensions of '_a.fit' and '_b.fit' referring to A- and B-beam positions, respectively. While most of the comet spectra were taken with slit widths of 0.5 and 0.8 arcsec, some of the standard star observations were made using wider slit widths, ranging up to 3.0 arcsec, as a means of determining accurate flux calibrations.  The following standard stars were observed for the purpose of flux calibration and telluric (atmospheric) corrections. Catalog abbreviations are: HD : Henry Draper Catalogue, HR : Harvard Revised Bright Star Catalogue. The V magnitudes listed are from various catalogues. References are given (when available) for the spectral classification.  Star V mag Spec_type HR 4689 3.89 A2IV [COWLEYETAL1969] HR 5107 3.40 A3V [COWLEYETAL1969] HR 5255 5.76 A0Vs [COWLEYETAL1969] HR 5332 (: HD 124683) 5.53 A0V [HOUK&SMITH-MOORE1988] HR 5959 5.53 A0Vs [COWLEYETAL1969] HR 6787 4.36 B2IV [LESH1968] HD 116960 8.00 A0V [WOOLLEYETAL1969] HD 122749 8.31 A0V [HOUK&SMITH-MOORE1988] HD 123309 9.40 A0V [HOUK&SMITH-MOORE1998] HD 144873 8.50 G5  On the nights of July 2 - 4 UT, low-resolution (prism-mode) spectra were rapidly recorded in 'movie mode'. For these observations, the telescope was not nodded (images acquired in the A-beam only), a sub-frame readout of the array was used in order to reduce the read time overhead, and the image sequences were stored in the form of 3-D fits image cubes. Each image cube has the dimensions 512x122x16 pixels. The fits header associated with each image cube contains the start and end times for the first and last frames contained in that cube. A text file associated with each image cube gives the GPS-derived time (minutes and seconds) at which the last pixel is read for each image plane stored in the cube. A near-infrared light curve of Comet 9P/Tempel 1 has been derived from the movie-mode data taken on July 4 (Fernandez et al. 2007) [FERNANDEZETAL2007].  The document directory also contains log files (plain text) for each night that spectra were obtained. These logs contain descriptions of the sky conditions and list the circumstances for each image frame (or image cube) including target name, start and end times, airmass, slit and grating. The last column contains a flag (Y or N) indicating whether spectroscopic and imaging data (with the guider array) were recorded simultaneously. When data were recorded simultaneously, the spectra can be directly compared to the on-slit images contained in the companion dataset, IRTF Near-IR Imaging of Comet 9P-Tempel 1 V1.0, in order to derive spectrophotometric results. By comparing the off- and on-slit images of the Comet and Standard stars in the imaging dataset, one can constrain the flux fraction passing through the spectrograph slit as a function of time. This is particularly useful in analyzing the spectroscopic 'movie' sequences taken around the time of the DI impact event.  While various spectral reduction packages exist, an IDL program called Spextool was developed specifically to reduce and extract spectral data taken with SpeX. The Spextool program is described in Cushing et al. (2004) [CUSHINGETAL2004]. The software is publicly available and can be download from the IRTF website.  These data were obtained through a coordinated effort by the following observers: Michael S. Kelley Neil Dello Russo Alan Tokunaga Carey Lisse Yan Fernandez

Confidence Level Overview : SpeX is a very stable instrument that produces consistently high quality data within the limits of instrument sensitivity. The spectrograph array is relatively clean of bad pixels, except for a cluster of hot pixels centered near array coordinate X : 605 Y : 770. In addition, there are two diagonal lines of dead pixels, roughly 2 pixels wide, that traverse the array. These lines can be masked and corrected for as part of the data reduction process (a procedure to deal with these lines is built into the Spextool reduction algorithm). The time stamps given in the image headers are accurately derived from a GPS signal.