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Help about noao.onedspec.deredden

SongHuang wrote on May 01, 2007

the deredden procedure need to know the A_v value to caculate the extinction, but if there are many spectrum to handle, is there any way can get the A_v value easier than check it by the position on NED site, the position of the objects in ra,dec have already been there in the header.

Thank you very much :shock:

SongHuang wrote on May 01, 2007

:cry: :cry: :cry: :cry: :cry:

Seem like no one notice my question.....

Mike Fitzpatrick wrote on May 01, 2007

Don't you know patience is a virtue 8-)

You would probably need to write a small script to do the processing, but as a first step see the DUST service at IPAC: http://irsa.ipac.caltech.edu/applications/DUST/

What I'm thinking is you would use the HSELECT task to extract the RA,DEC from each of the images to create the position table for upload, e.g.


cl> hselect *.fits ra,dec yes > coords


You would then need to edit this by hand to put it into the proper format for the upload (see the "service help" link on DUST for the format). Hit Submit to get the values for all the positions and then "Download Table" to get a text file of results. This gives you a table of positions and extinction values. The scripting part is in looping over this list to get the A_v value for the given position. Or, if you plan to run deredden by hand you've at least got a table of values you can enter quickly. Hope this helps.

Cheers,
-Mike

SongHuang wrote on May 01, 2007

Very helpful....Thank you very much

I'm just learn using IRAF, so maybe the question seem like a little stupid ,hope you don't mind :oops: :D

Last post on May 01, 2007