Spectral cutout service

[Petr Skoda]

Dear Doug,

Thank you for confirmation of my correct understanding of SSAP

> specify the region of interest (ROI), and if the service is a cutout
> service it computes a spectra to fit the ROI.  For a spectra, BAND
> is what gives you the cutout,

>> For typical lowres survey spectra cutouts are probably not that
> useful, but it should be a useful feature for any highres spectra.
> In particular it could be used to get line profiles.

It depends on what is lowres - our spectra from 2m coude spectrograph
may be considered lowres as well (R=12000) in comparison to echelles like 
ELODIE or FEROS (~50000), but I have seen studies from only Si or Mg lines 
in red region (6300-6400 A) and of course lot of Halfa or Hbeta lines only 
(especially for hot stars).
On B[e] stars lot of interest concerns only isolated forbidden lines of Fe 
or Oxygen.
And, of course, line profiles are crucial for asterosismology.

All of these are reasons, whay I want to have cutout service operating on 
or data archives. I hope to be able to give some talk about it in 
Baltimore(if everything comes out well).

> While this is the intention, I am yet not aware of any SSAP services that can 
> do cutouts.

We have found some way how to do it using the Pleinpot (due to my 
collaboration with Philippe Prugniel) - but he wants to have exact 
definition of such a service before modifying Pleinpot.

The most interesting question from him is:

How we know that the service is a cutout service ? We do not yet have 
GetCapability implemented (and approved in RFC) so the only way I see (and 
what was confirmed by Bob Hanisch) is simply another ServiceURL (another 
name of *.cgi in our case)..
Or is there another solution how to do it now in current standards ?
Phillipe's objection is the mess in delivering the results - the user has 
to control what he really wants to do with the data - see them all or get 
the selected range -- I think that it is clear - I would simply call 
another service which will be in Registry named as "archiv xxx cutout 
service  " with different ServiceURL. But what it should give in 
FORMAT=METADATA ?

> other capabilities, e.g., for association to describe complex data
> aggregations.
It is exactly what I would like to do in the future - delivering the 
individual echelle orders (somehow preprocessed...) - some clever way of 
presenting IRAF *.ec files .....

Best regards,


Petr Skoda

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*  Petr Skoda                         Phone : +420-323-649201, ext. 361 * 
*  Stellar Department                         +420-323-620361           *
*  Astronomical Institute AS CR       Fax   : +420-323-620250           *
*  251 65 Ondrejov                    e-mail: skoda at sunstel.asu.cas.cz  *
*  Czech Republic                                                       *
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