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Answers to common CIAO questions, including explanation of often-seen warnings and error messages.

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General

Data Products

1. When was my observation performed?
   When was the file created?
   What version of data processing was used?
2. What does the CREATOR header keyword mean?
3. What was the aimpoint of the observation?
4. What is the difference between the RA and DEC NOM, TARG, and PNT header keywords?
5. What is the focal plane temperature for my observation?
6. Why are there sometimes multiple asol1.fits files for my observation?
   How do I treat these in my analysis?
7. What is the CYCLE keyword?
   Should I be concerned if it's missing from my data?

Parameter Files

1. Why does the tool does not execute when I get the following error(s)?

   pget: parameter not found...

   parammatch : can't find parameter PARAMNAME in reference list
   parameter error?
             

2. Why should I delete my parameter files after upgrading CIAO?
3. How do I run multiple instances of a CIAO tool without clobbering the parameter file?
4. The tool is failing because ")sval" has somehow shown up in the parameter value.

Data Model

1. How do I change the MEM parameter when I get this error?

   # DMCOPY (CIAO 4.2): WARNING: Creating large image: 134 MB. Current max set at 50 MB.
   Increase maximum using [opt mem=n] or increase blocking to reduce size.
   

2. How can I define a region around a single chip?
3. Why should I filter on sky coordinates rather than the CCD_ID column?
4. How do I copy a block from one file to another?

ARDLIB

1. Why am I getting an ARDLIB error about a bad pixel file from a different ObsID?

   ***ARDLIB error: Unable to find data file acisf01842_000N002_bpix1.fits[BADPIX7]
   

2. What does this warning mean?

   ***ARDLIB warning: Filename some_file.fits does not specify an extension. 
   Assuming the first "interesting" extension.
   

3. How can I tell CIAO to use a different HRMA effective area file?

Computer Environment

1. What is a shell?
   What shell am I using?

Miscellaneous

1. Which CALDB version is installed on my system?
2. What is the limiting file size for CIAO?
3. What is the maximum size region file that CIAO can process?

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User Interface

ds9

1. Can I use a newer version of ds9 than the one packaged with CIAO?
2. How do I build polygon regions in ds9?
3. How do I rotate a region in ds9?
4. How do I display a source list on my data?

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Tools

acis_process_events

1. Why hasn't the CALDBVER keyword been updated after I run this tool?
2. Why is my level 2 event file larger than the one from the pipeline?
3. What does this warning mean?

   # acis_process_events (CIAO 4.2): The following error occurred 26941 times:
     dsAFEBADPCNTERR -- WARNING: Event island contains 1 or more bad pixels.
   

4. What does this warning mean?

   # acis_process_events (CIAO 4.2): WARNING: problem reading ctifile, cti adjustment will not be applied. Changing apply_cti=yes to apply_cti=no.
   

5. What does this warning mean?

   # acis_process_events (CIAO 4.2): The following error occurred 31 times: 
   WARNING: pulse height is less than split threshold when performing serial CTI adjustment.
   

acis_classify_hotpix / acis_run_hotpix

1. What does this warning mean?

   # acis_classify_hotpix (CIAO 4.2): WARNING: File /tmp/hotpixel_list.fits does not have any rows. 
   

aprates

1. What does this warning mean?

   # aprates (CIAO 4.2): WARNING: Large number of counts, just using Gaussian pdf 
   

asphist

1. What does this error mean?

   # asphist (CIAO 4.2): The difference of 2 asp_file counters should be 0 or 1. 
   

dmcopy

1. How can I specify the datatype of the output image?

dmextract

1. How do I extract many spectra with one command?
2. Why do I get a parse error with this region file?

   # Region file format: CIAO version 1.0	
   -rotbox(4055.375,4165.5674,4.6747966,4.4715447,63.400002)
   annulus(4059.5601,4163.4399,2.0325203,7.113821)
   

3. Why does dmextract convert arcseconds to arcminutes when I use pset?

dmimgthresh

1. How can I make a mask from an exposure file?

dmstat

1. How can I calculate the centroid of counts in a region?

dmtcalc

1. Why is the column moved to the end of the table when I try to update it in place?

hrc_process_events

1. What does this warning mean?

   # hrc_process_events (CIAO 4.2): The following error occurred 2482 times:
     dsHPEEVENTSEQERR -- WARNING: Out of sequence events discovered in hrc_evt1.fits.
   

2. What does this warning mean?

   # hrc_process_events (CIAO 4.2): The following error occurred 224 times:
           WARNING: can't find a proper degap value for this raw coord. in hrc_evt1.fits.
   

mkacisrmf

1. Since none of the files that are passed to mkacisrmf are aware of the date of my observation, how is the time-dependent gain included in the RMF?
2. Why do I get this error?

   # mkacisrmf (CIAO CIAO 4.2): ERROR: No non-zero pixels map to valid
   chip coordinates in the supplied wmap='src.pi[WMAP]' file
   

3. What does this warning mean?

   WARNING: Did not find 'GRATTYPE' in supplied header, skipping it 
   

mkexpmap

1. What does this warning mean?

   *** Warning: CYCLE not found or invalid in /tmp/imap_3.fits --- assuming 'P'
   

mkgarf

1. What does this warning mean?

   *** WARNING: The ARF was computed to be zero at all the specified energies.
                This is probably due to an incorrect source position
   

2. What does this warning mean?

   *** Warning: CYCLE not found or invalid in file.fits --- assuming 'P'
   

mkwarf

1. What does this warning mean?

   Couldn't determine chip position for pixel: (1013.000000,0.000000)
   with value=1.000000. Skipping pixel
   

tg_create_mask

1. What if the extraction regions extend beyond the detector edge?

tg_resolve_events

1. What does this warning mean?

   # tg_resolve_events (CIAO 4.2): The following error occurred 38950 times:
     WARNING: Event chip position is outside of valid range. 
     Grating coordinates not computed for this event.
   

2. What does this warning mean?

   # tg_resolve_events (CIAO 4.2): The following error occurred 10000 times:
           dsTREUNKNOWNINCOLERR -- WARNING: Not loading data from unrecognized level 1.5 input column.
   

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Scripts

fullgarf

1. Why do I get the following error?

   *** ERROR: aspect histogram acisf00459_ah4.fits[ASPHIST] contains no rows
   	  

2. Why do I get the following warnings?

   WARNING: OSIP file contains invalid data for the region
   512<=CHIPX<=768 608<=CHIPY<=640 at 0.1 keV.
   WARNING: OSIP file contains invalid data for the region
   512<=CHIPX<=768 608<=CHIPY<=640 at 0.277 keV.