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You will be prompted for information on the detector:
DETECTOR - Detector type (CCD or IPCS) /'ccd'/Answers are for the UHRF_X4 window. These values are used by the software to convert between pixels and mm - enter your<RET>DPIXEL_SIZE - Dispersion pixel size (microns) /24/24CPIXEL_SIZE - Cross-dispersion pixel size (microns) /196/96Do you want to run setup procedures [No] ?no
You cannot centre UHRF on any arbitrary wavelength. A control file must exist for your required wavelength centre.
The list of control files (complete to April 2000) is given in Section 2.4 and Appendix A4, and are held in the UCLES VAX account at DISK$USER:[UCLES.UHRF] (or /vaxuser/ucles/uhrf from unix machines). To check the current list, type:
If the file you need is missing, but you know the settings (e.g. in /epping/ras/uhrf/uhrf.settings) you can create a new control file:
DCL DIR DISK$USER:[UCLES.UHRF]
NOTE: If you need a new setting you should have contacted your support astronomer well in advance (> 1 week) so he/she can calculate a new file. The procedure for determining a new wavelength file is very time-consuming (see Appendix C11). However, small wavelength shifts (within the CCD frame) are not a problem.
creates a new UHRF control file. Specify the EMPIRICAL option when prompted, and enter the values requested, in encoder units. STILL WORKS? WHERE DOES IT GO?
USE DISK$USER:[UCLES.UHRF]filename Adopt the named control file.
CONFIG Configure the hardware using the control file specified by USE.
DISP or DISPLAY
displays spectrograph configuration. Check that the filters selection is correct (usually out of the beam). Items in motion are marked by asterixes (*'s). Reverse video emphasizes anything in an unusual state.
ADD AN EXAMPLE
DISP OUTPUT= filename
writes the display to an ASCII file.
reads a specific item, in default units e.g. R UG
RU item units
reads an item in specified units e.g. RU SW PIX
lists current configuration parameters
Many mechanisms have a limited range of travel. MIN and MAX are valid values to set them to their limits, e.g.SL MIN to obtain the shortest possible slit length. See Appendix C6 for a complete list of commands, and their limits.
Configure spectrograph to wavelength of interest and use a narrow binned window ( e.g. UHRF_X4).
There are two routines available:
Start the AAT utilities menu on aatssf by logging into obsred and typing AAT. The focus routine can be found under "setups" ? Run FOCUS and note the shift given in pixels (but IGNORE the prediction for the new collimator setting!).
Or run the FIGARO routine foc_unix.com. Copy /epping/ras/uhrf/foc_unix.com to your working account. Edit the file. It will contain a procedure something like:
Change the extract and ystract dimensions to match the location of the laser line. To run, type:
chmod u+x foc_unix.com
Make it executable
assign D /vaxdata/ccd_1/YYMMDD/ or correct path for exposures
foc_unix.com a b to run on dummy frames a.sdf and b.sdf
Calculate the focus shift from either routine by:
For every +1 pixel shift resulting from the cross correlation SCROSS
hp_up, move UFC/UFF by
-50 ADU at R = 1.0M,
-80 ADU at
R = 0.6M, and -170 ADU at R = 0.3M.
UFC and UFF read the same encoder, but differ in their positioning accuracy, so UFF must be used for setting within 50 ADUs. Moreover, UFF will position poorly for motions less than about 20 ADUs, so should be driven away by 50 ADUs and back again if necessary. MORE DETAILS
(Note that the HP UP configuration produces brighter spectra than the HP DOWN configuration.)
You should be able to achieve shifts of ~0.02 pixels. TRUE?
If at the laser wavelength, take exposure, YSTRACT a spectrum, and run EMLT to see the FWHM. For UHRF this should be about 50 um, = 2 Tek pixels UPDATE!
Repeat the procedure with the ThAr lamp at each required wavelength
The most likely parameters to change are:
adjust echelle dispersion position
Increasing UG moves the spectrum to the right. The Tek width in UG is about 1200 at R=0.3M; 600 at R=0.6M; 400 at R=1.0M.
Increasing UT moves the spectrum down. The Tek height in UT is about 2500 at R=0.3M; 1300 at R=0.6M; 800 at R=1.0M.
ADD MITLL2&3 - TABLE?
Once satisfactory grating and focus settings are obtained, they can be locked into the control files with
The geometric structure of the image slicer modulates the signal in the spatial direction. Also, all CCDs show some level of fringing in the far red wavelengths. This is clearly visible in the UHRF laser, ThAr, and quartz lamp exposures. Observers may find it useful to take flat field exposures not only through the image slicer but also through the slit, using the maximum slit length. These will provide more uniform illumination in the spatial direction which makes it easier to identify pixel-to-pixel variations.
switches to the slit
sets maximum slit length for continuous coverage.
ARC QUARTZ OK? - CHECK
turns on the lamp
Take flat field exposures.
turn off lamp
returns to slicer for observations.