Proposed FITS header for sensor (CCD) images (as of Oct. 2015)


(Jon Thaler) #1

Here EOTest_File_Spec_v5.pdf (343.1 KB) is the proposed FITS header for E2V sensor data. It has 16 extensions, one per amplifier.

The ITL sensors are slightly different:
“For example, I believe the e2V segments are each 512 x 2002 pixels, while the ITL segments are each 509 x 2000 pixels.” Craig Lange (cslage@UCDAVIS.EDU).


(Tony Johnson) #2

Hi Jon, the document you posted in mostly correct, but it is slightly out-of-date and for the details of current fits files from the test stands the sample files I previously sent you, which are also attached here:

https://confluence.slac.stanford.edu/display/LSSTCAM/More+fits+files+headers

are probably better references. The images attached there are simulated images, a similar image from a recent test stand run can be found here:

http://srs.slac.stanford.edu/DataCatalog/dataset.jsp?dataset=14162233

I am still actively working with Stuart to produce a raft level set of files using the most recent standards, we are very close but still don’t have a final file to send you.


(marshall) #3

For discussion regarding coordinate features in the viewer:

For both raft and CCD scale image viewing we would want:
1.) orientation:
- default to columns vertical on screen
- default to WCS- coordinate (1,1) at lower left of displayed image
- should be as though one is looking into the test-stand dewar from outside as opposed to from the detector plane looking out.

2.) Views:
- CCD:
- x,y in nominal pixel units (x parallel to serial register), w/overscan region displayed and switch for on/off of overscan coords and values
proposed
- x,y in nominal pixel units with overscan removed (call this one “trimmed”)
- Raft:
- x,y in nominal pixel units (x parallel to serial register), w/overscan region displayed and switch for on/off of overscan coords and values
- x,y in nominal pixel units with overscan removed (call this one “trimmed”)
- x,y in millimeter units reflecting as-built metrology (in the lab).

3.) Viewer capabilities to include (lots of other things, just calling out a few here)
- Ability to display 2+ sets of coords at a time (eg. CCD, amp, raft)

4.) Questions:
- naming conventions are needed:
- something like WCSNAME:PRIMARY for the wcs set that represents a whole “file” at whatever size we are using.
- and then WCSNAMEa:AMPLIFIER, WCSNAMEc:CCDTRIM, WCSNAMEd:CCDw/OSC, … this needs discussion
- will need to spec “wcsname, ctype?, cunit?, cdelti, PCi_j, crpix?”, are there others (and datasec, detsec?)