[Comm2011] Filters and MIDAS procedure

[E. Helmich]

Hi John,

About the second question: I'm afraid we may have a bigger problem with the
optical quality than a simple tilt. The PSF Anisotropy plots have fairly
complex systematics in them; when I run through the MIDAS procedure with
our focus sequences I likewise see something that simply is not well
described by a plane.

The way I go though the MIDAS procedure is like this:

Sketch of each CCD:

---------------  <---- overscan
_______________
_______________  <---- step function in background
_______________
        0         <---- last subexposure (real position in focal plane,
click first in MIDAS)
        0
        .
        .
        0         <---- first subexposure
_______________

1) Split.py on Focus sequence
2) Copy the split data to working dir
3) Delete all WCS header items from those files
4) "inmidas" to start midas
5) Open up the original MEF in skycat for reference and to see the location
of the step function (go through the list of extensions from top to bottom)
6) create/display
7) load/image <same extension as in skycat> scale=fit   (if you need to
shift a little use "center=1000,1000"
8) @ tplTFocus.prg
9) Paste filename of extension
10) Click through sequence from the last subexposure to the first
subexposure, right click to finish
11) Copy MIDAS output line (the one with the filename) to text file
12) clear/display
13) clear/graph
14) Go to next extension

Ewout


On Mon, 28 Mar 2011 13:10:51 +0200 (CEST), "John P. McFarland"
<mcfarland at astro.rug.nl> wrote:
> Hi Ewout,
> 
> I hope all is continuing to go well.  I have gone through the data to get
> the specifics of the filters into the system.  I have settled on some
> names
> and taken the specs from the PAE document VST-TRE-OCM-23100-3153.  It is
> from April 2004, but it is the newest one I can find.  If you know of a
> newer one or can find out about a newer one, please let me know.  It is
> not
> urgent as I can redefine the filters at any time, but certainly desirable
> to
> have the correct info on the first go.  Here are the specs I have:
> 
> FILT1 ID ->  AW name              CWL
> ---------------------------------------
> 'PS1'    -> 'OCAM_z_SDSS'        9100.0
> 'PS2'    -> 'OCAM_g_SDSS'        4775.0
> 'PS3'    -> 'OCAM_i_SDSS'        7630.0
> 'PS4'    -> 'OCAM_r_SDSS'        6230.0
> 'PS7'    -> 'OCAM_u_SDSS'        3550.0
> 'PS9'    -> 'OCAM_B_JOHN'        4562.5, # taken from WFI #842
> 'PS10'   -> 'OCAM_V_JOHN'        5395.6, # taken from WFI #843
> 'calib'  -> 'OCAM_u_g_r_i_SDSS'  3000.0
> 
> I have taken the header item 'HIERARCH ESO INS FILT1 ID' instead of
> 'HIERARCH ESO INS FILT1 NAME' as it is supposed to be unique.  I could
> take
> the other one, but I expect conflicts there.  Please let me know if you
> see
> any issues with this listing.  Thanks.
> 
> Also, can you give me the location of your MIDAS procedure and a brief
> run-down of the MIDAS commands (e.g., image/load, etc.) I need to use it
> on
> the focus data.  I would like to replicate your results on the tilt as
> soon
> as possible.  Thanks.
> 
> Cheers,
> 
> 
> -=John