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Hi,I've encountered some problem in using the TWODSPEC.LONGSLIT.FITCOORDS
task. I'm using IRAF v2.12.2 on linux/Fedora Core 4.I've run the IDENTIFY and REIDENTIFY tasks in determining the dispersion
solution every 10 lines. However, when trying to use FITCOORDS it displays
the following warning:longslit> fit
Images whose coordinates are to be fit (arc01): arclamp01
Fit arclamp01 interactively (yes): NOAO/IRAF V2.12.2-EXPORT bonitade@bonita-de-swardt.fsc.uct.ac.za Tue
10:11:37 27-Jun-2006
Longslit coordinate fit name is arclamp01.
Longslit database is database.
Features from images:
arclamp01
Warning: No coordinates found in databaseeven though the file (idarclamp01 in my case) does exist in the database
folder.I don't know what I'm doing wrong and will greatly appreciate your help.Thank you,
Bonita

Hi Bonita,When you first assign values to features in IDENTIFY, either actual arc coordinates or pixel values to calibrate in pixels or for S-distortion, these values are then carried through REIDENTIFY. However, it is possible if you are confused at the IDENTIFY stage to have features whose reference value is INDEF. FITCOORDS ignored these INDEF values. This is the most likely cause of the message. You should look into the database/id<image> file and see what it looks like and if anything seems funny to you. If you aren't sure you can post a snippet of this and I'll tell you if there is anything wrongMy only other thought is somehow you are refering to information incorrectly. That is what FITCOORDS is looking for is not what you did with IDENTIFY/REIDENTIFY. You can send me the parameters you used for IDENTIFY and FITCOORDS and maybe I would see something there.Yours,
Frank Valdes

Dear Frank,My "idarclamp01" contains the following:begin identify arclamp01 - Ap 1
id arclamp01
task identify
image arclamp01 - Ap 1
aperture 1
aplow 893.08
aphigh 1073.08
units Angstroms
features 66
114.15 3914.78462 3914.7675 12.0 1 1
156.75 3925.73261 3925.7188 12.0 1 1
168.00 3928.61875 3928.6233 12.0 1 1
183.10 3932.48625 3932.5466 12.0 1 1
236.78 3946.19784 3946.0971 12.0 1 1
247.38 3948.89903 3948.9789 12.0 1 1
262.34 3952.70636 3952.7291 12.0 1 1
323.97 3968.3632 3968.3594 12.0 1 1
348.23 3974.51183 3974.4766 12.0 1 1
367.45 3979.37597 3979.3559 12.0 1 1
417.80 3992.09527 3992.0535 12.0 1 1
428.41 3994.77271 3994.7918 12.0 1 1
470.41 4005.34935 4005.3628 12.0 1 1
504.08 4013.81287 4013.8566 12.0 1 1
585.33 4034.17508 4033.8093 12.0 1 0
603.98 4038.83554 4038.8043 12.0 1 1
660.32 4052.88691 4052.9208 12.0 1 1
737.25 4072.00117 4072.0047 12.0 1 1
866.33 4103.87449 4103.9121 12.0 1 1
903.06 4112.89712 4112.8153 12.0 1 1
979.94 4131.71399 4131.7235 12.0 1 1
1090.32 4158.56469 4158.5905 12.0 1 1I don't see any reason why it should have a problem in doing the fitting.These are the parameters I've been using for the Identify and Reidentify tasks:longslit> lpar identify
images = "arclamp01" Images containing features to be identified
crval = Approximate coordinate (at reference pixel)
cdelt = Approximate dispersion
(section = "middle line") Section to apply to two dimensional images
(database = "database") Database in which to record feature data
(coordlist = "linelists$cuar.dat") User coordinate list
(units = "") Coordinate units
(nsum = "10") Number of lines/columns/bands to sum in 2D images
(match = -3.) Coordinate list matching limit
(maxfeatures = 80) Maximum number of features for automatic identification
(zwidth = 100.) Zoom graph width in user units
(ftype = "emission") Feature type
(fwidth = 12.) Feature width in pixels
(cradius = 5.) Centering radius in pixels
(threshold = 0.) Feature threshold for centering
(minsep = 2.) Minimum pixel separation
(function = "legendre") Coordinate function
(order = 5) Order of coordinate function
(sample = "*") Coordinate sample regions
(niterate = 1) Rejection iterations
(low_reject = 3.) Lower rejection sigma
(high_reject = 3.) Upper rejection sigma
(grow = 0.) Rejection growing radius
(autowrite = no) Automatically write to database
(graphics = "stdgraph") Graphics output device
(cursor = "") Graphics cursor input
(aidpars = "") Automatic identification algorithm parameters
(mode = "ql")
longslit> lpar reidentify
reference = "arclamp01" Reference image
images = "arclamp01" Images to be reidentified
answer = "yes" Fit dispersion function interactively?
crval = Approximate coordinate (at reference pixel)
cdelt = Approximate dispersion
(interactive = "yes") Interactive fitting?
(section = "middle line") Section to apply to two dimensional images
(newaps = yes) Reidentify apertures in images not in reference?
(override = yes) Override previous solutions?
(refit = yes) Refit coordinate function?\n
(trace = no) Trace reference image?
(step = "10") Step in lines/columns/bands for tracing an image
(nsum = "10") Number of lines/columns/bands to sum
(shift = "0.") Shift to add to reference features (INDEF to search)
(search = 0.) Search radius
(nlost = 0) Maximum number of features which may be lost\n
(cradius = 5.) Centering radius
(threshold = 0.) Feature threshold for centering
(addfeatures = no) Add features from a line list?
(coordlist = "linelists$cuar.dat") User coordinate list
(match = -3.) Coordinate list matching limit
(maxfeatures = 50) Maximum number of features for automatic identification
(minsep = 2.) Minimum pixel separation\n
(database = "database") Database
(logfiles = "logfile") List of log files
(plotfile = "") Plot file for residuals
(verbose = yes) Verbose output?
(graphics = "stdgraph") Graphics output device
(cursor = "") Graphics cursor input\n
(aidpars = "") Automatic identification algorithm parameters
(mode = "ql")I've just been following the reduction procedure for longslit spectra in "A User's Guide to Reducing Slit Spectra with IRAF" (April 1992). It's quite crucial that I align the slit along each column before extracting spectra at various positions along the slit.Thanks for your help.
Bonita

Hello Bonita,Thank you for the additional information. What I see is that you have[code:1:c5acdf775d]begin identify arclamp01 - Ap 1[/code:1:c5acdf775d]This indicated that identify thought it was working on an extracted 1D spectrum. You probably ran APEXTRACT? Note that even if you have extracted multiple spectra into a "multispec" image, which looks like a 2D image, the code treats this not as a longslit image but as a collection of 1D spectra. In this case using the long slit methods of FITCOORDS and TRANSFORM is not correct. Instead you continue calibration with 1D tasks such as DISPCOR.Note that when you trace a 2D long slit image the database results from IDENTIFY/REIDENTIFY look like:[code:1:c5acdf775d]
# Mon 09:59:00 03-Jul-2006
begin identify demostd[*,256]
id demostd
task identify
image demostd[*,256]
units Angstroms
features 1
50.01 50.0058708 50. 4.0 1 1# Mon 09:59:00 03-Jul-2006
begin identify demostd[*,246]
id demostd
task identify
image demostd[*,246]
units Angstroms
features 1
50.21 50. 50. 4.0 1 1
shift -0.2089080810546875# Mon 09:59:00 03-Jul-2006
begin identify demostd[*,236]
[/code:1:c5acdf775d]Let me know what you did to your data prior to running IDENITFY if you are still not sure what to do. Following the guide is a good idea but be sure to see that it primarily talks about extracting stellar spectra with APEXTRACT. The case of working in 2D is, I believe without consulting the document, in an appendix.Yours,
Frank

Hi Frank,Your previous comments were very helpful. It seems that reidentify created an output file called "arclamp01" in the database subdirectory. When I ran the fitcoords task, it was looking for an output file "arclamp01[1]" which includes the image extension. So, the problem was with the naming of the output file.I think that I'm not naming my files correctly because I now have the "transform" task giving an error saying "no user coordinates". I'm quite sure that the output of fitcoords is OK but could you please check it for me. I'm not sure if there is a problem with the fitcoords output file or the naming of my files, even though I've checked that I'm using the correct fc<file name> in database.This is the output fitcoords gives (it names the file "fcarclamp01[1]"): # Thu 10:23:50 06-Jul-2006
begin arclamp01[1]
task fitcoords
axis 1
units angstroms
surface 44
1.
6.
6.
1.
1.
3162.
1.
2049.
4255.607761837479
368.1375569846769
-10.95546617701304
-0.5348731374142966
0.1069095297717146
-0.08022543346351081
-0.4698049734944008
-0.1634181064416855
0.8637280463729169
-0.8574805745526482
0.9952927076616798
-0.4953547287507184
-8.961625350450356
-0.193334711552735
0.05366421936042482
-0.05555247666919418
0.1475520226546977
-0.121551175062965
-0.2362034630130662
-0.09865828778717634
0.4649735835277021
-0.4723945646180846
0.5569869633448213
-0.2710863595565997
0.06706642359529548
0.05529995471513079
0.01008267668093476
-0.02013200514011926
0.04513953560274697
-0.03544802029877148
-0.06118864646161261
-0.03044635016452341
0.1178667690802925
-0.1200374750595047
0.1429402220012306
-0.06589566279011181At the moment, I want to use the transform task to align the comparison lines exactly with the y-axis. But I'm not sure why it's not finding the output of fitcoords.Thanks,
Bonita

Hi Bonita,Frank is on vacation at the moment, but your last message rings a bell with me. Try updating to the V2.12.2a patch (or the V2.13 beta), there were changes made to fitcoords following the V2.12.2 release specifically to deal with extensions in the filenames. You can get the patch files fromftp://iraf.noao.edu/iraf/v212/PCIX/patch2a/You'll need a new set of binaries (the ib.rhux.x86 and nb.rhux.x86 files) and the source patch file 'patch2a.tar.gz' that you should unpack in the iraf root directory. Hope this helps.Cheers,
-Mike