[INSTRM-484] Update FITS headers based on Subaru feedback of MCS example PFSC00005800

Relates — Mon, 29 May 2023 03:06:21 +0000

In the email [PFS-Soft-Subaru:551] Hisanori Furusawa raised the following comments on the MCS FITS file example supplied by cloomis. These comments should be reviewed and implemented.

General comments to the whole headers

1. Could you provide a keyword dictionary that describes a range of values
and value format for each keyword?

2. We recommend to add WCS to the 2nd HDU (compressed image extension),
since it would benefit PFS commissioning as well as users, considering
this is the only data representing fiber positions on a 2-d plane without
dispersion.

Comments to HDU1

3. Missing mandatory keywords (labeled 'Common' in the current Subaru Basic
FITS header dictionary)

DET-TMP
GAIN (recommend a typical value here, and use W_XXX keywords for
different amplifiers)
LST

*1) except NAXIS1, NAXIS2; these two are always required in the current
rule,
but the new rule will not require this if NAXIS=0)
*2) missing keywords relevant to image extension are listed in the HDU2
section

4. Check value range for the below 4 keywords:

OBS-ALOC
OBS-MOD
FOC-POS
IMR-TYPE

We need to confirm that these keywords follow the rule and make sure
values are surely registered in the rule.

5. Inconsistent inline comment for UT and HST keywords

should be "HH:MM:SS.SSS ..." not "..SS.SS ..."
UT = '00:25:27.402' / HH:MM:SS.SS typical UTC at exposure
UT-STR = '00:25:27.402' / HH:MM:SS.SS UTC at exposure start
UT-END = '00:25:28.402' / HH:MM:SS.SS UTC at exposure end
HST = '14:25:27.402' / HH:MM:SS.SS typical HST at exposure
HST-STR = '14:25:27.402' / HH:MM:SS.SS HST at exposure start
HST-END = '14:25:28.402' / HH:MM:SS.SS HST at exposure end

6. Registration of the new keywords to the Basic FITS header dictionary
is required:

M2-POS3, M2-ANG3

7. Instrument-specific keywords (W_*) are not separated from a set of
basic keywords by appropriate comment lines

e..g, W_VISIT, W_M2OFF[1-3]

The new rule will allow similar/related basic & W_* keywords are
grouped in a place without separation.
Still appropriate comment lines are recommended.

8. If MCS camera uses any filter in the light path, we recommend to add
keyword 'FILTER01'

9. M2-TYPE should be 'IR'. Subaru plans to fix Gen2 for this.

10. Inline comment is required for these keywords:

EXTEND, DET-ID

11. Inline comments for FRAMEID and EXP-ID are the same.
More appropriate comments to describe the difference would be preferred.

12. General comment to Inline comment:
Inline comment wording should be derived from the Basic FITS header
dictionary for basic keywords whenever possible.
For archive users, the same keywords should have the same comments across
the instruments and data kinds.

13. EXP-ID should have 'E' in the 4th letter

14. DATA-TYP=ACQUISITION is recommended. To be discussed with PFS team

15. Make sure DETECTOR should be an identifier for a detector
If replaced, it will have a different value.

16. Wrong keyword names:

ADC-TYP --> ADC-TYPE
IMG-TYP --> IMG-TYPE

17. Inconsistent format of values

Please have them reviewed by PFS team.

ADC-STR (F20.3)
AZIMUTH, ALTITUDE (F20.5)
AIRMASS (F20.3)
DOM-PRS DOM-WND (F20.2)
EXPTIME (F20.2)
FOC-VAL (F20.3)
INST-PA (F20.3)
INR-STR, IMR-STR (F20.3)
M2-POS[1-3], M2-ANG[1-3] (F20.3)
MJD, MJD-STR, MJD-END (F20.8)
OUT-PRS OUT-WND (F20.2)
SEEING (F20.2)
TRANSP (F20.3)
ZD (F20.5)

18. Unnecessary keywords may be omitted
It might be worth considering to remove them to avoid potential confusion.

e.g., IMR* (if IMR is not used) , ADC* (if ADC is not used)

Comments to HDU2

19. Missing mandatory keywords (labeled 'Common' in the current Subaru
Basic FITS header dictionary)

BIN-FCT[1-2]
BLANK
BUNIT
WCS keywords - we recommend to include the WCS keywords for MCS data
CRPIX[1-2], CRVAL[1-2], CTYPE[1-2], CUNIT[1-2]
and (CD[1-2] or (PC[1-2][1-2], CDELT[1-2])) etc.

*) relevant to image extension only

20. Inline comment is required for these keywords:

BSCALE, BZERO

21. Subaru will update FITS rule including multi-extension FITS

22. There seem no problem with keywords for Tile Image Compression

23. Please make sure if ZPCOUNT, ZGCOUNT are necessary.

24. Please make sure keywords relevant to 'image data' as they are
in this HDU, in addition to the keywords for Tiled-image compression.
This would include:
BZERO, BSCALKE, WCS keywords etc.

PFS-JIRA

[INSTRM-484] Update FITS headers based on Subaru feedback of MCS example PFSC00005800