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The Data Products Guide describes the contents and purpose of each Chandra data product. Detailed information is available for each of the following filetypes:

• event files
• PHA/spectrum files
• images
• aspect solution
• good time intervals and the mission timeline

These pages may also be accessed from the tables of data products.

This document is a work in progress. For the most up-to-date description of the common Chandra data products, refer to the Introduction to the Data Products thread.

Primary Products

In March 2002, the data products were rearranged such that all products necessary for most analyses are in the primary directory.

Instrum	Level	Data product	File Type	Pipeline	Filename template
ACIS	L2	Events	EVENTS	ACIS2	acis*_evt2.fits
ACIS	L2	TG Events	EVENTS	TG2	acis*_evt2.fits
ACIS	L2	HIRESIMG	IMAGE	ACIS2	acis*_cntr_img2.fits
ACIS	L2	LORESIMG	IMAGE	ACIS2	acis*_full_img2.fits
ACIS	L2	Spectrum	SPECTRUM	TG2	acis*_pha2.fits
ACIS	L2	Source list	SRCLIST	ACIS2	acis*_src2.fits
ACIS	L1	Bad Pix	BADPIX	ACIS1	acis*_bpix1.fits
HRC	L2	Events	EVENTS	HRC2	hrc*_evt2.fits
HRC	L2	TG Events	EVENTS	TG2	hrc*_evt2.fits
HRC	L2	HIRESIMG	IMAGE	HRC2	hrc*_cntr_img2.fits
HRC	L2	LORESIMG	IMAGE	HRC2	hrc*_full_img2.fits
HRC	L2	Spectrum	SPECTRUM	TG2	hrc*_pha2.fits
HRC	L2	Source list	SRCLIST	HRC2	hrc*_src2.fits
HRC	L1	Bad Pix	BADPIX	HRC1	hrc*_bpix1.fits
HRC	L1	Livetime	DTF	HRC1	hrc*_dtf1.fits
PCAD	L1	Aspect solution	ASOL	ASP1	pcad*_asol1.fits
Orbit	L1	Orbit ephemeris	ORBITEPHEM	EPHEM1	orbit*_eph1.fits

Secondary Products

If you are interested in reprocessing your data, you will also need the level 1 files, which are in the secondary directory.

Instrum	Level	Data product	HDU name	Pipeline	Filename Template
ACIS	L1	Events	EVENTS	ACIS1	acis*_evt1.fits
ACIS	L1	GTI	GTI/MTL	ACIS1	acis*_flt1.fits
ACIS	L1	Mission Timline	GTI/MTL	ACIS1	acis*_mtl1.fits
ACIS	L1	Bias	BIAS	ACIS1	acis*_bias0.fits
ACIS	L1	Exp. Stats	EXPSTATS	ACIS1	acis*_stat1.fits
ACIS	L1	Mask	MASK	ACIS1	acis*_msk1.fits
ACIS	L1	Alignm. offsets	ALIGN	ACIS1	acis*_soff1.fits
ACIS	L1	Aspect offsets	ASPOFF	ACIS1	acis*_aoff1.fits
HRC	L1	Events	EVENTS	HRC1	hrc*_evt1.fits
HRC	L1	GTI	GTI/MTL	HRC1	hrc*_std_flt1.fits
HRC	L1	Mission Timline	GTI/MTL	HRC1	hrc*_mtl1.fits
HRC	L1	Livetime stats	DTFSTATS	HRC1	hrc*_std_dtfstat1.fits
HRC	L1	Alignm. offsets	ALIGN	HRC1	hrc*_soff1.fits
HRC	L1	Aspect offsets	ASPOFF	HRC1	hrc*_aoff1.fits
PCAD	L1	Aspect quality	ASPQUAL	ASP1	pcad*_aqual1.fits
PCAD	L1	OBC aspect sol.	ASOL	ASP1	pcad*_osol1.fits
Solar	L1	Solar ephemeris	SOLAREPHEM	EPHEM1	solar*_eph1.fits
Lunar	L1	Lunar ephemeris	LUNAREPHEM	EPHEM1	lunar*_eph1.fits
Angles	L1	Viewing angles	ANGLES	EPHEM1	angles*_eph1.fits

Supporting Products

The pipeline-produced supporting products are generally not needed in data analysis. These files are created by intermediate processing steps.

Instrum	Level	Data product	HDU name	Pipeline	Filename Template
ACIS	L1.5	TG Events	EVENTS	TG1.5	acis*_evt1a.fits
HRC	L1.5	TG Events	EVENTS	TG1.5	hrc*_evt1a.fits
HRC	L1.5	TG Source list	SRCLIST	TG1.5	hrc*_src1a.fits