From Tbalonek@mail.colgate.edu Tue Aug 14 10:30:48 2001 Date: Wed, 1 Aug 2001 00:55:12 -0400 From: Tom Balonek To: 'Roban Hultman Kramer' , "'Martin, Stephan E'" Cc: "'Pasachoff, Jay'" , "'Kwitter, Karen'" Subject: RE: Roper Scientific / Princeton Instruments SPE headers Roban & Steve, I have looked over your IDL scripts and images available on your web page. I agree that you've extracted values correctly and your comments on the web page, Roban, on the date format and exposure length are correct. Turns out that since you are using WinView 2.4.4, whereas I'm using 2.5.3, there is a difference in our header structure! My code is based on version 2.5.3 with the header format I emailed you in a previous email (cheader.h file). Thus the output from my program of your sample image (the email I sent July 31 at 6:32 pm) has a few errors in the parameters: headver, contver, intrface, timelocl and time_utc (the time is stored in a different location for the two versions), shutcont; and a few header parameters which appear for my system but not for yours. I won't be able to get to it this week (my summer students are leaving at the end of the week and I need to spend some more time with them), but I think I can generalize my code to be able to see the difference between 2.4.4 and 2.5.3 headers. Now that I have sample images from each system I should be able to "reverse engineer" some of Roper's assignments (i.e. a "20" seems to correspond to Controller Interface type PCI Timer!). I do have a copy of version 2.4.8.7 of their code, so I can also do some tests of that version sometime. I will be modifying my code so that one can just extract the image header if one wants. Then you could attach this image header to your current FITS files... . For the future, I recommend you (Williams College) get version 2.5.3 of WinView/32 from Roper since there appears to be information that the new version puts in the spe header. Two important parameters included in the new header are: the time of exposure (in local and UT time) is in a more convenient format, the chip temperature. It looks like version 2.5.3 can read version 2.4.4 files, since I was able to open your image and read the header. If you want to probe the Roper SPE header, you can use the octal dump command on a Linux/Unix machine. In case you don't know about octal dumps, use examples: od -j 30 -N2 -i filename returns hour of time of exposure od -j 10 -N4 -f filename returns the exposure time od -j 20 -N9 -s filename returns date of exposure ddmmmyyyy Note -j means jump (skip) bytes, -N means number of bytes, -s means string of characters, -f means floating point number, -i means integer. "man od" in Linux/Unix gives you more information on octal dump. Using octal dump is how I deciphered the Roper header (and thus finding where their printed manual was wrong!). Do you folks use the calibration header parameters? I don't do any of these conversions, but notice your code does. I can add this to my program if needed. Thanks for getting images and files to me. It really helped -- and hopefully I have helped you. If you need to chat more about this, let me know. I'm around afternoons. Tom *-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*- Thomas J. Balonek Dept. of Physics and Astronomy email: tbalonek@mail.colgate.edu Colgate University http://astronomy.colgate.edu/ 13 Oak Dr. phone: 315-228-7767 Hamilton, NY 13346 fax: 315-228-7187 *-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*- > ---------- > From: Roban Hultman Kramer > Sent: Tuesday, July 31, 2001 4:36 PM > To: Tbalonek@mail.colgate.edu > Cc: Jay.M.Pasachoff@williams.edu; Stephan E. Martin > Subject: Re: Roper Scientific / Princeton Instruments SPE headers > > Hi, > I am a Swarthmore student doing a Keck fellowship at Williams this > summer. I'm working on the experiment that used the VersArray with > WinView and spent some time wrestling with the headers, as well. My notes > on what I've done, along with the sample files and header info you wanted > are available here: > http://www.sccs.swarthmore.edu/~roban/temperature/conversion/conversion.ht > ml > > I'd like to talk with you more about what problems you've encountered in > your own efforts. It sounds like you've already achieved much more > generality than I have at this point. Let me know if I can do any more to > help. > > -Roban Hultman Kramer > Swarthmore 2003 > Astrophysics >