Ah. You don't want Astro::FITS::Header, you want this page:
http://fits.gsfc.nasa.gov/fits_standard.html
It's at GSFC so you may or may not be able to get it today!
The main things that may trip you up are:
-all keywords are case-insensitive - if you're making a FITS header from a
perl hash that isn't tied to Astro::FITS::Header, you should make them ALL CAPS
-non-alphanumeric characters are mostly not allowed (hyphens and underscores
*are* allowed)
-8 characters is the max length of a keyword.
-FITS headers come in increments of 24 80-character fixed-length Hollerith
card images WITH NO RETURN-CARRIAGE AT THE END. That's because FITS was
invented when Hollerith cards were commonly found around computers.
-69 characters is the max length of a string value (80 per card image; 8 of
them are for the keyword, 1 for the '=', and 2 for the quotes around the
string).
A basic minimum header for an image is:
$h = {SIMPLE=>T,
NAXIS=>2,
NAXIS1=> $im->dim(0),
NAXIS2=> $im->dim(1),
DATATYPE => -32, # for float type; use -64 for double
END => ' '
}
Keyword order matters, so if you're using a Perl hash you need to write
particular keywords in a particular order into the FITS file. Have a look at
PDL::IO::FITS - the wfits method contains some contingency code in case
Astro::FITS::Header isn't available.
On Oct 1, 2013, at 4:24 PM, duckyphysics <[email protected]> wrote:
> Thanks. I gave the referring URL in my initial message:
> http://pdl.perl.org/PDLdocs/Core.html
>
> The Astro package is referenced several times on that page. I'm actually
> trying to obtain (or at least read the documentation for) Astro::FITS::Header
> because I want to create a valid FITS header from scratch that will behave
> correctly in SAODS9. When I try to set keywords in a perl hash, not all of
> them are propagated through to the final image that DS9 sees.
>
>
>
>> You'll have to give the URL of the page referring to the dead
>> link for it to be removed or fixed. Astro::FITS::Header is not
>> in the PDL distribution so maybe that is why the link doesn't go
>> anywhere. The docs are available via perldoc if you have the
>> module installed, or http://search.cpan.org or http://metacpan.org
>> if needed.
>>
>> --Chris
>>
>>
>> On Mon, Sep 30, 2013 at 8:00 PM, duckyphysics <[email protected]> wrote:
>>> Hello,
>>>
>>> I was following a link from http://pdl.perl.org/PDLdocs/Core.html to
>>> http://pdl.perl.org/Astro/FITS/Header.html, but the latter is dead. Upon
>>> further investigation, everything under /Astro gives 404. The page provides
>>> the following error text:
>>>
>>> --
>>> An error has been encountered in accessing this page.
>>>
>>> 1. Server: pdl.perl.org
>>> 2. URL path: /Astro/FITS/Header.html
>>> 3. Error notes: NONE
>>> 4. Error type: 404
>>> 5. Request method: GET
>>> 6. Request query string: NONE
>>> 7. Time: 2013-09-30 23:47:36 UTC (1380584856)
>>> --
>>>
>>> Thanks.
>>> _______________________________________________
>>> Perldl mailing list
>>> [email protected]
>>> http://mailman.jach.hawaii.edu/mailman/listinfo/perldl
>
>
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