Thermal Infrared Multimode Instrument


TIMMI-2 data products

Raw data products

One observation of a scientific target typically contains many chopping (M2) and (one or more) nodding(telescope offsets) cycles. The number of video frames per nod position (FITS header keyword: HIERARCH ESO PRO REDU XPECT VIDEO, HIERACH ESO ...) and the number of nod positions (HIERARCH ESO PRO REDU XPECT MINOR, or HIERARCH ESO ....) are defined within the observing block. The final number of video frames for one observing block is then equal to VIDEO*MINOR (see also the explanation given here.

The format of the data cube has changed: the firts plane now contains the HCYCLE1 frame while the secoind plane contains the chopped image. PLease see note ofn the pipeline for data reduction.

The directory structure is defined as follows:

A so_called major number of the filename is derived from the time (UT) of the start of the observing block in the format ymmddhhmm (year/month/day/hour/minute). The observing mode corresponds to the mode describing the observing block (e.g. IMAGING or SPECTRUM or POL). A root directory of the type major_mode_object is created that contains all data logically connected to this observing block. (E.g. 104100151_imag_HD108903 means that object HD108903 (HIERARCC ESO OBS NAME) has been observed in imaging mode on 2001-Apr-10 at 01:51 UT). Within this directory, a number of subdirectories are created, one for each nodding position, and numbered by 5 digits nnnnn. E.g. 00001, 00002, 00003 and 00004. The total number of nodding position is contained in the fits keyword MINOR. Finally, these directories contain the individual video frames written in this nod position, as defined with the fits keyword VIDEO. Each individual video frame corresponds to one physical fits image (320*240*2) written to disk (plane 1: chopped image; plane 2: staring image background). The filename convention is major-minor-sequ_in.fits.gz, sequ being a 4 digit running number.

All the ESO VLT-compliant are available in the FITS headers. We are working such that the ISAAC/SoFI keywords be included such as CUMULOFFSET and RELOFFSET.

Pipeline processed data:

The version of the pipepline delivered by Vienna is no longer compatible with the new data format, please contact ls-infrared@eso.org for informations. The new version does not include any of the TUI's anymore, since they have become obsolete.

The raw data cubes are processed in an online pipeline for coadding and nodding correction. Bad pixels are removed, and an effective area of 300*220 pixels is extracted. The results are two dimensional, simple FITS images, intended for a fast look of the data. Successfully processed data are stored in a subdirectory called result/major.fits.

Because the pipeline "expect" a certain number of frames, only the observations successfully executed are being completely reduced (hence stored in the result directory). The next step will be to include nonetheless the "aborted" sequences.

Caution: these so_called "pipeline" processed data are NOT intended to save a careful off-line reduction by the user that should include additional steps like bad plane removal, noise filtering, or shift and add processing.

WE do not forsee any problem with the IR reduction software Eclipse, however it has not been tested yet.


New log files are provide with the copy of the data CD for the observer. Here is a exemple:


Observation name
<------- File name --------> <--Program--> <-Template->
ExpTim <-- RA --> <-- Dec --> <-- LST--> <-- UTC--> <Airm> <CHOP ampl> <NOD ampl>
Instrument and Optical elements
Detector N/DIT and Lamps
V838Mon - 70.D-0660(C) SCIENCE IMAGE Reduced
0.02s 07:04:05 -03:51:05 05:24:48 05:43:51 - - arcsec - arcsec
TIMMI2: 0.2arc/pix N-imag_0.2/pix OUT 0. 10.4_OCLI
IRACE: 80x[2* 60]* 3x 0.02msec

This is under developement and should be ready for December 2002.

Data distribution

Each morning, 3p6 telescope day operation staff produce CD-Rs containing nightly TIMMI-2 data. The CD-Rs are given to the visiting astronomer before leaving the mountain. A typical observing night with TIMMI2 produces 2GB of raw data. The CD-Rs contain all raw data recorded that night as gzipped FITS files, and the pipeline processed data. The 3p6 stores backup copies, and in case of problems reading the data, the visiting astronomer can approach the team (ls-infrared@eso.org)


Send comments to <ls-infrared@eso.org>
Last update: 12 Mar 2001 
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