NetNews Usenet Archive 1992 #27/NN_1992_27.iso/spool/sci/astro/12212

Internet Message Format | 1992-11-19 | 1.6 KB

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From: [e-mail] (Mike Newberry)
Newsgroups: sci.astro
Subject: Re: st6 images wanted
Message-ID: <[e-mail]>
Date: 19 Nov 92 21:45:24 GMT
References: <[e-mail]>
Sender: [e-mail]
Organization: University of Arizona, Tucson, AZ
Lines: 22

In article <[e-mail]> jscherer@db (John Scherer) writes:
>
> recently downloaded st6 images from sunlight.physics.uiowa.edu, but found that
> the images are 8-bit.  From what I know about the st-6, it is capable of 16-bit images.  I would like to see some 16-bit images if there available..
>
> John Scherer
> [e-mail]

You should fetch the *.fts.Z files instead of the *.gif files.  You'll have
to use the unix uncompress to turn the .Z file into a binary uncompressed
data file. This file will be in "FITS" format, a standard used throughout the
astronomical world. If you do not have software which will read FITS format,
you can use the following recipe:

Skip the first 2880 bytes of the file, as this contains the file information
"header" in FITS format. Starting at byte offset 2880 will be found binary,
uncompressed, unpadded pixel data. The pixels are unsigned 16-bit integers,
so watch out if unsigned integers might choke your software--these images do
have values above 32767. To turn this binary raster file into a 2-dimensional
image, note that there are 375 2-byte pixels in each row. There are 242 rows.

Mike Newberry