Spitzer Documentation & Tools
IRS Instrument Handbook

6.2  File Naming Convention

6.2.1             Raw and Level 1 (BCD) Data

The Raw and Level 1 (BCD) files within the raw/ and bcd/ download directories (see Table 6.1) adhere to the following naming convention:

SPITZER_S+module_aorkey_expid_dcenum_version_type.suffix

where

·         S+module = S0, S1, S2, or S3. These correspond to Short-Low (SL), Short-High (SH), Long-Low (LL), or Long-High (LH), respectively. S0 also corresponds to peak-up data.

·         aorkey = Unique ID number for each AOR.

·         expid = Exposure ID number. This denotes a distinct array exposure command. The value of expid depends on how many FOV positions (see Section 6.6.4) are used. For example, with all 4 modules exercised in staring mode, there would be the following values of expid:

SL2 nod 1:  expid=1

SL2 nod 2:  expid=2

SH nod 1:   expid=3

SH nod 2:   expid=4

LL2 nod 1:   expid=5

LL2 nod 2:   expid=6

LL1 nod 1:   expid=7

LL1 nod 2:   expid=8

LH nod 1:     expid=9

LH nod 2:    expid=10

If only LL2 and LH are exercised:

LL2 nod 1:  expid=1

LL2 nod 2:  expid=2

LH  nod 1:   expid=3

LH  nod 2:   expid=4

For a 2x2 map in SL1:

SL1 center, posn 1: expid=1

SL1 center, posn 2: expid=2

SL1 center, posn 3: expid=3

SL1 center, posn 4: expid=4

·         dcenum = The nth exposure in a sequence, at a given spatial position.

·         version = A counter that is incremented each time a data set is re-processed, starting at 1 for the first processing.

·         type = The type of pipeline product, e.g. bcd, coa2d.

·         suffix = The file format, e.g. fits, tbl.

For example, one might find the following file in the archive:

SPITZER_S0_21247232_0005_0002_7_bcd.fits

In this case,

S+module = S0, indicating that this is a SL or peak-up observation.

aorkey =  21247232

expid = 0005.

dcenum = 0002.

version = 7, meaning that these data have been reprocessed 7 times, though various versions of the Spitzer pipeline (see Chapter 5).

type = bcd, meaning that this is a Basic Calibrated Data file.

suffix = fits, meaning that this is a FITS format file.

6.2.2             Level 2 (PBCD) Data

The Level 2 (PBCD) files within the pbcd/ download directory (see Table 6.1) adhere to a naming convention similar to that used for Level 1 (BCD) data (see 6.2.1). The parameters aorkey, expid, and version are still used to identify the observation. However, dcenum is not used. Instead, an additional “ensemble number” (“E” for ensemble product, or “A” for ancillary ensemble product, followed by the ensemble product ID) is inserted. An example of a Level 2 (PBCD) file is:

SPITZER_S0_21247232_0005_7_E5138813_coa2d.fits

S+module = S0

aorkey =  21247232

expid = 0005.

version = 7, meaning that these data have been reprocessed 7 times, though various versions of the Spitzer pipeline (see Chapter 5).

ensemble product ID = 5138813

type = coa2d, meaning that this is a co-added data file (see Chapter 5).

suffix = fits, meaning that this is a FITS format file.

6.2.3             Calibration Data

Because the calibration files used to produce the data products are the same for many different AORs they appear without any reference to AOR, cycle number, etc.