[Comm2011] Filters and MIDAS procedure

[E. Helmich]

Oh, something else about Tilt:

Koen quickly realised that we missed something important: 1 millimeter
shift by the M2 does NOT equal 1 millimeter shift at/of the focal plane.
Koen and Pietro determined that there is a factor of almost exactly 10 in
between (1mm M2 = 10mm focal plane).

Another factor is the M2 step size. We've used several values: 0.02mm,
0.01mm, and 0.005mm, but they are not stored in the header. The focus image
I've analysed is
FOCUS087_0004

this morning I'll do
FOCUS087_0005

They were only observed last night, so I'm not sure they've arrived in
Garching yet. For Focus sequences of night 086, well I wouldn't use them
(though they can be used to confirm/deny the qualitative statement that
we're dealing with more complicated effects than a plane). Some of them
have best focus outside the range, because we used 0.005mm steps, other
issues as well.

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