iraf.net

Hello! Having a slight problem with IRAF here (running X11 port on Cygwin for Windows XP). I'm analyzing a star field with imexamine, and when I try to do a , on certain stars, I get "ERROR: arithmetic exception", and the program leaves the package. I can measure some objects in the field, mostly dimmer ones. Many of the brighter objects give me this error. Does anyone know why this is happening, and how to fix it (if that's possible)? Thanks!

Without seeing the data or your parameters it's hard to say more than an 'arithmetic exception' is something like a divide-by-zero, log() of a negative number, etc. It is sometimes a coding error but in a heavily used command/task more often it is data or parameter related. Try unlearning the task and resetting the params slowly to see whether it makes a difference. You might also look at the pixel values with the 'z' key to see if they "should work". Otherwise, please post a url to the image and your parameters (i.e. "cl> dpar imexam").Cheers,
-Mike

Thanks! I used "z" and here are the pixels on one of the "bad" stars, taken as close to its center as I could get it:[code:1:f680c8c196] 390 391 392 393 394 395 396 397 398 399 400
442 55.99 70.72 89.43 112.7 128. 159.9 162.1 173.8 175.7 146.9 122.1
441 63.19 79.76 102.3 127.6 169.7 192.6 216.3 220.1 214.1 189. 142.7
440 69.85 83.83 114.9 151.7 196.2 221.7 249.9 253. 240.5 221.1 183.6
439 73.39 100.2 134.8 162.5 198.1 247.6 263.1 276.8 267.9 222.9 199.4
438 74.57 104.6 133.4 159.8 213.1 230.8 272.8 275.3 263.3 225.2 178.1
437 76.65 95.43 123.3 169.1 195.7 214.4 250.8 249. 230.2 205. 166.7
436 69.11 93.4 112.9 141.6 175.3 199.2 209.5 226.2 215.2 174.5 151.9
435 68.15 80.59 93.79 123.1 149.3 165.7 175.3 170.3 167.7 148.4 128.1
434 56.72 62.53 89.11 96.17 118.7 126.2 141.9 135.1 126.9 114.9 101.1
433 45. 46.08 62.15 80.17 88.81 99.65 107.7 110.8 96.94 81.88 73.7
432 45.2 45.09 52.54 61.61 60.27 73.38 76.12 87.75 66.8 65. 54.75
[/code:1:f680c8c196]So I see nothing wrong but maybe I'm missing something. My parameters are:imexamine.input = "*10-25.fits"
imexamine.frame = 1
imexamine.image =
imexamine.output = ""
imexamine.ncoutput = 101
imexamine.nloutput = 101
imexamine.logfile = "log.txt"
imexamine.keeplog = yes
imexamine.defkey = "a"
imexamine.autoredraw = yes
imexamine.allframes = yes
imexamine.nframes = 0
imexamine.ncstat = 5
imexamine.nlstat = 5
imexamine.graphcur = ""
imexamine.imagecur = ""
imexamine.wcs = "logical"
imexamine.xformat = ""
imexamine.yformat = ""
imexamine.graphics = "stdgraph"
imexamine.display = "display(image='$1',frame=$2)"
imexamine.use_display = yes
imexamine.mode = "ql"
rimexam.banner = yes
rimexam.title = ""
rimexam.xlabel = "Radius"
rimexam.ylabel = "Pixel Value"
rimexam.fitplot = yes
rimexam.fittype = "moffat"
rimexam.center = yes
rimexam.background = yes
rimexam.radius = 3.
rimexam.buffer = 12.
rimexam.width = 12.
rimexam.iterations = 1
rimexam.xorder = 0
rimexam.yorder = 0
rimexam.magzero = 25.
rimexam.beta = INDEF
rimexam.rplot = 8.
rimexam.x1 = INDEF
rimexam.x2 = INDEF
rimexam.y1 = INDEF
rimexam.y2 = INDEF
rimexam.pointmode = yes
rimexam.marker = "plus"
rimexam.szmarker = 1.
rimexam.logx = no
rimexam.logy = no
rimexam.box = yes
rimexam.ticklabels = yes
rimexam.majrx = 5
rimexam.minrx = 5
rimexam.majry = 5
rimexam.minry = 5
rimexam.round = no
rimexam.mode = "ql"(Included rimexam since I changed its parameters a bit, too).For some reason, pressing "a" works fine, I don't get the same error. Any thoughts are appreciated, thanks!

The profile fitting algorithm is complex and is known to occasionally have problems with certain data. If you can extract a subraster (imcopy with an image sections) that continues to reproduce the error I would be glad to diagnose it. Send me an email with the small image attached or else place it at ftp://iraf.noao.edu/pub and let me know about it.Yours,
Frank Valdes