About IMAPS Data

IMAPS-2

Currently, only the IMAPS-1 data is releaseable. IMAPS-2 was expected to become available but the data was never archived at MAST.

IMAPS-1

The original IMAPS data was stored as IDL unformatted data sets. The raw data was later converted to FITS format files by the staff members at the ADF (see NSSDC). The FITS headers were extensively modified by Goddard LASP personnel, and the resulting raw image files are now available via the WEB or anonymous FTP at archive.stsci.edu in the /pub/orfeus/imaps/data/raw directory. An effort is currently underway by LASP personnel to archive the coadded, corrected raw data. These data are corrected for image distortion, face plate artifacts, etc. but the spectra must still be extracted (although wavelength assignments will be included). IDL software will be made available to read and extract data using these files.

IMAPS data sets are uniquely defined using the "Exposure Sequence Number". The first archived file is number 079 and the last image is number 721. The current naming convention is imaps1_0nnn.fits, where nnn is the exposure sequence number. The coadded files will use the naming convention imaps1_0nnn-0mmm.fits where nnn is the first coadded image and mmm is the last coadded image. (It is assumed that all intervening images are included in the coaddition.)

A table of the IMAPS1 observations (obtained from the EXPOLOG.DAT file written by Ed Jenkins) is shown below. The total integration time is an estimate for the total amount of observation time devoted to each object. The exposure sequence numbers describe the number and sequence of the individual observations. The numbers in parentheses indicate the number of frames used in the eta UMa exposures (511 frames were used for all others). Background exposures are not included in the table.

Object Name	Total Integration Time (sec)	Exposure Sequence Numbers
gamma2 Vel	1476	89-108 239-251 323-330
zeta Ori	2412	109-124 195-214 378-408
zeta Pup	1476	125-140 276-294 440-445
gamma Cas	1872	141-148 220-238 331-355
epsilon Ori	1836	150-173 296-322
alpha Eri	2088	175-194 253-274 416-424 715-721
beta Cru	946	356-375 410-415
eta UMa (atmos. probe)	3432	447-454 (511) 455-514 (255) 515-522 (511) 525-532 (511) 533-592 (255) 594-601 (511)
kappa Ori	3456	602-649 653-700
beta Cen	288	702-713

Spectral Resolution and Sensitivity

The plot below shows the spectral sensitivity and resolution of IMAPS compared to other recent UV detectors (courtesy of Derck Massa, Raytheon STX, Goddard Space Flight Center).