Appendix C: Connection between AOTs, OSNs, Files and Measurements

Though the connection is described in the IDUM (Isophot Data User Manual), a brief summary is given here. We will not pay too much attention to the file name systematics; instead we will try to explain the connection between the structures.

As an example, let us consider a set of AOTs, the TDT-number of each AOT being 013014 (concatenated AOTs). The AOTs are distinguished simply by the OSN:

The raw data of each AOT/OSN are stored in a single ERD file. However, the "unit" on which programme processing works is a measurement (and not a file) and one file may contain several measurements. The information about the measurements can be obtained from the Compact Status Files . PIA provides an easy look at them. Of course, the results of various measurements may be combined later in the Astrophysical Applications.

Let us consider two examples:

1. Example for the AOT PHT03 (OSN 01):

The Edited Raw Data are stored in the ERD file PPER01301401.FITS. This file contains 9 measurements corresponding to the various wavelengths (and detectors):

• There are 5 measurements with detector P1, namely 1 FCS measurement and 4 "target" measurements at 3.6, 10, 11.5, 16 micron.
• There are 2 measurements with detector P2, namely 1 FCS measurement and 1 "target" measurement at 25 micron.
• There are 2 measurements with detector P3, namely 1 FCS measurement and 1 "target" measurement at 60 micron.

The Standard Processed Data are stored in the 3 Pipeline SPD files PP1S01301401.FITS, PP2S01301401.FITS and PP3S01301401.FITS (corresponding to the three detectors P1, P2 and P3). These files contain only 6 (=4, 1 and 1) measurements corresponding to the 6 target measurements. (The 3 FCS measurements of the ERD file are no longer contained in the SPD files.)

Within PIA the storing is done into one SPD file per measurement, e.g.: PPmm01301401.ISPD with mm = number of the measurement - 1

2. Example for the AOT PHT22 (OSN 03):

The Edited Raw Data are stored in the file P1ER01301403.FITS. This file contains several (actually 9) measurements according to the different wavelengths:

• There are 3 measurements with detector C100, namely 2 FCS measurements and 1 "target" measurement at 60 micron which itself is composed of 9 different pointings (it is a raster map).

The same "construction" is repeaated for 90 and 100 micron:

• There are 3 measurements with detector C100, namely 2 FCS measurements and 1 "target" measurement at 90 micron.
• There are 2 measurements with detector C100, namely 2 FCS measurements and 1 "target" measurement at 100 micron.

The Standard Processed Data are stored in the Pipeline SPD file PC1S01301403.FITS. This file contains 3 measurements corresponding to the 3 maps. (The 6 FCS measurements of the ERD file are not contained anymore in the SPD file.)

Within PIA the storing is done into one SPD file per measurement, e.g.: C1mm01301401.ISPD with mm = number of the measurement - 1

Independently of the different storing systematics, PIA is able to read all the Pipeline files. Though there may remain some questions, these remarks should have attracted the user's attention to the difference between files and measurements, and how to identify his data.