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Filter mapping

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spp
spp's picture
Filter mapping

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spp
spp's picture
Filter mapping

In the telescope profiles setup there is an option for fits header FILTER mapping.   I'm starting a project in which I'll be using filters from different manufacturers.  I'd like to indicate the fliter sources in the header, but have VPhot use the standard filter name.  

Does the mapping tool recognize wildcard characters in the header value, i.e  *V or ????V, where the wildcards would indicate the filter manufacturer?  Thus,  the FILTER values ADONV (for Astrodon V) and CHRMV (Chroma V) would both be mapped to V for VPhot.

Phil

MZK
MZK's picture
Experiment?

Hi Phil:

Theoretically, I could look in the VPhot code and see how the Fits Header "value" is read and what format is expected. However, I think it would be easier to just try it? Fits headers certainly can have alphanumeric characters and some symbols as can be seen in the Telescop header that includes ACP<... So there is some hope that VPhot would read the header terms that you are proposing. The question is whether VPhot was coded to "only read/accept" specific values. That is certainly true in the sense that VPhot will only understand specific filter values but I think it will read/report them but just be misunderstood? So, if you set up the mapping terms correctly, I think it would work? Try it out and tell us! Should only take a few minutes. 

Ken

spp
spp's picture
wildcards don't work

Ken,

I edited the header of an old photometry V image, changing FILTER value from V to ASTDV (for Astrodon V}.  I set the filter mapping rule for ????V  = V, and saved the change.   When I uploaded the image, the Filter column in available images showed ASTDV. 

No soap.

Is there a VPhot  "things to change someday when we get around to it" list?  I think being able to use wildcards in filter mapping would be useful.

Phil

 

 

MZK
MZK's picture
ASTDV

Phil:

I assumed that you would try to map ASTDV to V, not ????V to V. As you noted, VPhot was smart enough to read ASTDV in the header. You will not have an infinite number of different header values so I would think using the specific header filter value would be okay. Can't you map the few (?) specific values you need. I don't think this is something many people would need/want to do? No?

Ken

spp
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wild cards in FILTER mapping

"I assumed that you would try to map ASTDV to V, not ????V to V."

Ken,

The experiment was not to see if the the FILTER mapping tool worked for any explicit value for FILTER.  It was to see if wild card characters worked.  Using "ASTDV" was the test to see if VPhot would convert that to V.  It didn't.

"You will not have an infinite number of different header values so I would think using the specific header filter value would be okay. Can't you map the few (?) specific values you need?" 

I don't know how many specific value mappings VPhot will allow, but in my case that would be quite inconvenient even if it were possible.  There are other ways to do this (keep track of the manufacturer of each filter).  I think using wild cards for the FILTER value would have been good because it would keep the manufacturer information in the header.

"I don't think this is something many people would need/want to do?"

I don't know if others would find it useful.  I know it would have been helpful to me.

Phil

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