Record of clocks/biases (from 2018_sep)

 On loose paper in the cabinet, with electronics drawings, found notes regarding clocks & biases from 9/2018 that I think were written down by Kevin Hanna when we were having detector issues.  Preserving them here for posterity.  Provides a little more information than Ed's post from 4/2018 - the function for each clock/bias channel.

Low mode dispersion with positive and negative orders

 Did a comparison of low resolution in order = +1 and order = -1.  Looking at wn0 = 399 cm-1 with H2O lines from the gas cell.  Used slit 1 to limit light and dekker ~33 degrees for short slit.  

Note that dispersion direction is reversed from what we're used to in negative orders.

I rotated the order=-1 image by 180 degrees so it was the same orientation as the +1 image.  I then rectified by hand (slightly different angle required: 5.88 degrees for +1 order and 5.85 degrees for -1).  I then extracted 11 rows near the center of each spectrum and summed.  I subtracted off the median and took the absolute value so now got emission spectra.

Looking carefully, you can see that the negative order dispersion is less than the positive

I fit gaussians (with baseline) to all 7 lines in both spectra.  I then called the centroid of the first line on the left as pixel 0.  I found the difference in separation between the leftmost line and the rightmost line and took the ratio.  The order = -1 dispersion was 98% of the order = +1 dispersion.  

After correcting for the dispersion to first order, the lines lie pretty much on top of each other.

Spring 2021 Window + Wheel Updates

Window Update

 Installed new CsI window (replaced spare window which was flown with during Feb 2020 series)

Wheel Update

Wheel Slot Filter Filter 1 open Filter 2 BBP5500 + MgF2 Filter 3 N07904 + MgF2 Filter 4 Reading 6.2um + MgF2 Filter 5 N07053 + CaF2 Filter 6 N07466 + CaF2 Filter 7 BP14100 Filter 8 Soifer Filter 9 OCLI ‘O’ + CaF2 Filter 10 Reading 18um Filter 11 Filter 12 BP13465 + BaF2 Filter slot 12 is wider Dekker 1 Dekker 2 BP6000+BaF2 Dekker 3 BP6600+MgF2 Dekker 4 removed BBP5030+MgF2 Lens 1 OPEN Lens 2 BP13465+BaF2 Lens 3 N04679+MgF2 Lens 4 BP6000+BaF2 Lens 5 BP6600+MgF2 Lens 6 BBP5030+MgF2

Recalculating Spatial scale for cross-dispersed modes, HIGH_MED and HIGH_LOW using header keywords

(correct) SLTH_PIX=                   65 / Slit height in pixels                          

(wrong) SLTH_ARC=               11.173 / Slit height in arcseconds     

The final pipeline products have these keywords, but the second one is wrong because of a misstep in the EXES_READHDR and EXES_TESTTORT routines. The past data archive is too large to correct without a concerted effort, but using Matt's email below, we can find the correct slit height in arcsec with just the information available in the headers of the pipeline products.

SLTH_PIX is correct. It is the average number of spatial pixels found on the orders of flat field, and adopted for the reduction. 

The other header keyword "ECHELLE" is the input angle, alpha and that lets us correctly calculate the slit height in arcsec, accounting for the anamorphic magnification

These lines of IDL will return a better value for the slit height

hdr=headfits("*SPC*") ; or "*WVM*

npix = sxpar(hdr,"SLTH_PIX")

alpha = sxpar(hdr,"ECHELLE")

pixscale0=0.201 ; arcsec

delta=5.43

slitheight=pixscale0 * cos((alpha + 5.43)*!dtor)/cos(alpha*!dtor)*npix

print, slitheight

Matt's email, Feb 3, 2021

"Hi Curtis (I added everyone else since anamorphic magnification is, I think, an interesting optical property of using gratings in plane diffraction (as opposed to Littrow)),

If you want to read all the details, it is in this post and its comments:  

http://codgermmck.blogspot.com/2016/08/hi-med-spatial-plate-scale-with-fcls_26.html

If you just want the formula, it is:

observed platescale = platescale * cos(beta)/cos(alpha) 

where 

platescale = 0.201"/pixel

alpha = input angle (from header)

beta = alpha + delta = output angle

delta = 5.43 degrees = difference between input and output beams.  

delta, remember,  was supposed to be, I thought, 2.715 degrees or half of the number required to fit the data.  I wonder if I got the half angle stuck in my head.  Curtis, do you remember how far apart the input and output beams are on the cross-disperser mirror?  

John's drawing of zemax beams on the acad components (optics+zemax.jpg in eE/optics is probably the best place to see it) makes it look like a little less than 2" between beam centers. With 40" as the distance from the echelle grating to the mirror, atan(2/40.) = 2.86 degrees which is close to my 2.715 degree number, so I'm still confused unless the input/output beams are more like 4" apart.

-matt"

End plate screwdriver map

When we just recently opened up EXES, the sticky notes with screwdriver directions were coming off.  I took a picture and created this drawing as a record.

CD042 Filter and Dekker Wheel Config

CD042 Filter and Dekker Wheel Config

Wheel	Slot	Filter
Filter	1	open
Filter	2	BBP5500+MgF2
Filter	3	N07904+MgF2
Filter	4	Reading 6.2um + MgF2
Filter	5	N07053+CaF2
Filter	6	N07466+CaF2
Filter	7	N04679+MgF2
Filter	8	Soifer
Filter	9	OCLI 'S' + BaF2
Filter	10	Reading 18um
Filter	11	BP14100
Filter	12	BP13465+BaF2
Dekker	1	OCLI ‘O’+CaF2
Dekker	2	BP6000+BaF2
Dekker	3	BP6600+MgF2
Dekker	4	BBP5030+MgF2