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Dear IRAF,I have two questions that I'd like your help with please.1. I have a POSS fits image that I've 'display'ed and would like to run
'imexamine' on in order to get the RA and Dec coordinates for certain
stars. When I type 'a' to get a stellar position, the output is not of
sufficient accuracy in RA: for example, it gives 7:34:32.4 and I'd like at
least one more significant figure for the seconds. How do I get this?
(The Dec is fine, since 0.1" accuracy is sufficient. But 0.1s isn't.)2. I've taken some time now to learn to use daophot in IRAF with great
success. I have confidence I'm doing things correctly. Where my problem
lies is that I have photometric observations in 4 filters of the same
field. I'm having trouble combining the xxx.als.n files for the various
filters into one table or file so that information for any given star is
readily available in a single row/record. At this point, I have four
xxx.als. files and I have to edit these by hand in Excel to ensure they
have the same number of rows and then sort them in order of star ID or
whatever and then concatenate by hand, etc. Very time consuming and
unsatisfying. Can you tell me how I might do this more elegantly and
efficiently?Thanks very much.Michael (De Robertis)======================================================================
Michael De Robertis
Assoc. Dean, Faculty Affairs & Research
Faculty of Science and Engineering E-mail: mmdr@yorku.ca
York University Phone: 416-736-5051 (voice)
4700 Keele St. FAX: 416-736-5950
Toronto, ON M3J 1P3 URL: www.science.yorku.ca

[quote:b38d8fbdbe]1. I have a POSS fits image that I've 'display'ed and would like to run
'imexamine' on in order to get the RA and Dec coordinates for certain
stars. When I type 'a' to get a stellar position, the output is not of
sufficient accuracy in RA: for example, it gives 7:34:32.4 and I'd like at
least one more significant figure for the seconds. How do I get this?[/quote:b38d8fbdbe]Try something like[code:1:b38d8fbdbe]cl> imexam wcs=world xformat="%.2H" yformat="%.2h"[/code:1:b38d8fbdbe]will give you two decimals in each coordinate. See the IMEXAM help page description of the parameters for details.[code:1:b38d8fbdbe]
2. I've taken some time now to learn to use daophot in IRAF with great
success. I have confidence I'm doing things correctly. Where my problem
lies is that I have photometric observations in 4 filters of the same
field. I'm having trouble combining the xxx.als.n files for the various
filters into one table or file so that information for any given star is
readily available in a single row/record. At this point, I have four
xxx.als. files and I have to edit these by hand in Excel to ensure they
have the same number of rows and then sort them in order of star ID or
whatever and then concatenate by hand, etc. Very time consuming and
unsatisfying. Can you tell me how I might do this more elegantly and
efficiently? [/code:1:b38d8fbdbe]Try the TMATCH task if you're able to match on e.g. the star coordinates. Since you're matching multiple catalogs you'll probably want to do this in stages within a script. TJOIN is another option is there is a common column with the same value. Both tasks are in the TABLES external package.-Mike[/quote]