How to focus the detector at F1 and F3
Make sure the Dewar of the detector is completely filled with
liquid nitrogen. Be careful with N2!
1. But the odometer on the frame of the mount of the F1 focus such
that it pushes the mount of the detector. There is a mark
on the mount which gives the rough position of the focus. Use this
position as a first guess.
Focussing F3 is slighly more complicated. For F1 the position
of the detector is changed to focus. For F3 the mirror in front
of the detector (about 1 meter off=3 feet to the east) is moved
to reach focus. To move this mirro, first unscrew the mount, than
move the mirror and plate, and than tighten the screws again. The
odometer gives the position.
2. Put the narrowest slit (#1) in slit 2 (which leads to F1 and F3)
3. In the Coude room (one floor below the laser room):
make sure that the light from the ThAr lamp is reflected into
the spectrograph. If not rotate the mirrors so that it will do.
Use slit 2 position by rotation to "#5 Mirror (Sliver), slit #2)"
If you want to beam the SKY (after opening the SKY cap) to
the F1 or F3 focus put the rotating plate on "Slit #2, Solar Mirror"
4. Go to the laser room and turn the ThAr lamp on:
* "turn the "COMPARISON LAMP SUPPLY" on
* Voltage at 250 V
* Current at 15 Amp
* put the "STANDBY" switch on "ON"
5. One panel below the "COMPARISON LAMP SUPPLY" is the control box
for the mirrors.
* put "LAMP STAGE" on "CS2". Light from the lamp will now be
fed to spectrograph
* put "GUIDER" on "SLIT"
* the "MASK A" and "MASK B" switch should be out of order (no light burning)
6. goto "atlas" and go to subdirectory "ICE"
7. start IRAF by typing "cl" (command language)
8. within IRAF load package ICEX by typing "icex"
9. and go to your data directory by typing "cd /data2/atlas/ejb"
10. edit "detpars"
(firstcol = 1) First column of data (device coordinates)
(lastcol = 2048) Last column of data (device coordinates)
(firstrow = 1) First row of data (device coordinates)
(lastrow = 2048) Last row of data (device coordinates)
(colbin = "1") Column binning factor
(rowbin = 2) Row binning factor
(preflash = 0) Preflash time in seconds
(gain = 0) Instrumental gain setting (0 for default)
(detinfo = "") Optional image header info about detector
(detcap = "runlib$detcap") Detector capabilities file
(detname = "tk3") Detector name
(detpix = "l") Data type of detector pix (u=16-bit l=18-bit)
(integrator = "2") Detector integrator (1=slow 2=medium 3=fast)
(amplifier = "1") Detector amplifier
(nframes = "") IRDetector sum/average nframes
(angle = 0) Detector angle from nominal
(regions = "") Selected regions of the detector to readout
(mode = "ql")
11. edit "instrpars"
if using F1 + E2 cs21-e2
if using F3 + E2 cs23-e2 and typically tiltpos=5818 order=0
if using F1 + E1 cs21-e1
if using F1 + E1 cs23-e1
(instrfilters = "") filter bolt positions
(aperture = "") aperture
(tvfilt = "") tv filter
(complamp = " ") comparison lamp
(probepos = " ") probe position file
(disperser = "") disperser
(tiltpos = "") tilt position
(order = "5328") spectral order (0 = most efficient)
(decker = "0") decker
(instrfocus = "") instrument focus
(posangle = "") position angle
(dispaxis = "") dispersion axis
(fts = "") filter translation
(filtoffs = "") filter offset values
(polarizer = "") polarizer angle in degrees
(instrinfo = "") Optional image header info about instrument
(instrcap = "runlib$instrcap") Instrument capabilities file
(instrname = "cs21-e2") Instrument name
(mode = "ql")
12. edit "telpars"
(dateobs = "") date (dd/mm/yy) of observation
(ut = "") universal time (hh:mm:ss)
(st = "") sidereal time (hh:mm:ss)
(ra = "") right ascension (hh:mm:ss)
(dec = "") declination (dd:mm:ss)
(epoch = "") epoch of ra and dec
(ha = "") hour angle (hh:mm:ss)
(zd = "") zenith distance (dd:mm:ss)
(airmass = "") airmass
(telfocus = "") telescope focus
(telfilters = "") filter bolt positions
(rotangle = "") rotation angle
(pressure = "") barometer
(teltemp = "") telescope temperature
(windspeed = "") wind speed
(winddirectio = "") wind direction
(humidity = "") humidity
(seeing = "") seeing
(pointsrc = "") point source info
(pointdir = "") optional point source directory info
(pointtype = "mean") point type header info
(aperture = 0.) telescope aperture size (m)
(focalratio = ) telescope focal ratio
(telinfo = "") Optional image header info about telescope
(telcap = "runlib$telcap") Telescope capabilities file
(telname = "mcd107") Telescope name
(mode = "ql")
13. edit "obspar"
exposuretime = 120. Exposure time (seconds)
imagetype = "comp" Image type
objecttitle = "ThAr" Object title
nfexpo = 7 Number of focus exposures
shtype = "detector" Shift type
focmode = "manual" Focus mode
fstart = Starting focus value
fdelta = "" Focus increment
nrvrows = 30 Number of rows to reverse shift
(rootname = "ejb") Image root name
(sequence = 316) Sequence number
(setfilters = no) Query and set filters?
(setfocus = no) Query and set focus?
(setscanrows = no) Query and set nscanrows? (short scan mode)
(filtype = "telescope") Type of filters to use
(foctype = "telescope") Type of focus to use
(pixtype = "l") Data type of IRAF pixels
(observers = "ejb") Observers
(comments = "") Comments
(comfile = "") Observer header comments file
(obsinfo = "") Optional observing information for image header
(observatory = "MCDONALD") Observatory name
(command = "display %s 1") Postprocessing command
(preallocate = 60) Preallocate image (0=no 1=yes N=if exptime > N)
(preprefix = "imdir$") Preallocate image prefix
(longexpo = 300.) Long exposure time (seconds)
(verbose = yes) Type out image name?
(debug = no)
(mode = "ql")
14. check echelle status by typing "instrument". This will move
the echelle and prism to the required position. If you
get an error message type in "flpr" (=flipper) and try it
again. If you still get an error. goto 13 and loop again.
16. Make sure you have ximtool or saoimage running. If you
don't, then go to another window and type under unix "ximtool &"
or "saoimage &". This will pop up a display window.
15. You're now set to make a test integration.
go to the directory where you want to store your data: e.g,
"cd /data2/atlas/ejb"
edit "epar test"
nexpo = 1 Number of exposures
imagetype = "object" Image type
exptime = 180. Exposure time (seconds)
(objecttitle = "test") Object title
(verify = no) Verify image deletion?
(verbose = yes)
(mode = "ql")
Type in "test" and respectively "1" "object" and "180"
OR if you want to save the CCD frame in a numbered file
on disk:
type "observe"
(obspars = "") observing parameters
(detpars = "") detector parameters
(instrpars = "") instrument parameters
(telpars = "") telescope parameters
(mode = "ql")
16. After 180 seconds and 55 seconds reading type the image
will be displayed on ximtool.
17. in iraf type "imex" to stars imexan program
18. goto the display and put the cursor (circle) on top of a
spectral line and type in "j". A plot window will pop up
showing a Gaussian fit to the spectral line. In the right
upper corner of the plot the FWHM is give in number of pixels
This should be of the order of 2.2 to 2.8 pixels.
Do this for about 6 isolated lines and take the average.
19. Now change the focus position (the odometer) by 0.20 and
repeat the test.
20. Change the odometer again and find the position at which
the FWHM is smallest. This gives you the focus position.
Leave the F1 focus at that position. If you change central
wavelength there is no need to focus again. Just leave it
the way it is.
21. The resolution is given by: R=5328/(FWHM*24e-3*0.40)
For FWHM=2.83 this gives R=195000
F1 June 9 1996 F1 Aug 10 1996
cs21-e2+TK3 cs21-e2+TK3
tiltpos=5328, order=65 4234.5 #81
dlambda/dx=0.40 dlambda/dx=0.335
slit width R(June 9) R(Aug 9)
1 86mm 0.20 " 203,000 216,000
2 145 0.34 182,000 195,000
3 251 0.59 137,000 139,000
4 511 1.20 74,000 69,000
5 765 1.79 52,000 48,000
6 1010 2.37 40,000 37,000
-Note that for Echelle E2, only slit #1..6 can be used. For slit
which are longer the orders will overlap.
-R=lambda/(FWHM*24e-3*dlambda/dx).
-about averaging over 7 ThAr lines per slit.
F3 June 10 1996
cs23-e2+TK3
tiltpos=5382 angstrom, order=64
R=5382/(FWHM*24e-3*1.789)
(averaging over 6 ThAr lines per slit)
slit width FWHM R (5382 and 1.780A/mm)
1 86mm 0.20arc-sec 1.47pixels 86,000
2 145 0.34 1.50 84,000
3 251 0.59 1.60 79,000
4 511 1.20 2.17 58,000
5 765 1.79 2.78 45,000
6 1010 2.37 3.62 35,000
last update: June 11 1996 by ejb