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Images showing as not calibrated

Ed Wiley_WEY's picture
Ed Wiley_WEY
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Joined: 2010-08-30

I have had all images that were reduced with API4WIN showing as "uncalibrated" when uploaded to VPhot. Is this usual when reducing with API4WIN? Or am I missing something in the fits header that I should be including during the reduction process? From the header "History Calibrated."

Thanks for any input, Ed

uncalibrated
spp's picture
spp
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Joined: 2010-07-25

Ed,

VPhot wants an standard FITS "keyword" in the header to determine if the image is calibrated.  A comment in the "History" field won't do it.

Katy asked your question during the course.  You'll find it in the "Plate solving and WCS" thread in the VPhot course forum.

Here's the answer from Mike.

"To Katy From Geir,

There are different ways, but the easiest is to put 'BDF' into a field named 'CALSTAT' in the header. B for bias subtracted, D for dark and F for flat. Or DF if only dark and flatted, etc."

 

(me again)

But it's not that simple.  The syntax has to be exactly right.  The keyword has to be left justified 8 characters.  Since CALSTAT is only 7 character you must include a space at the end, also lots more rules.  You can find the rules on page 61 of the "Handbook of Astronomical Image Processing" (Berry and Burnell), 2nd edition.

I believe the proper syntax is:      CALSTAT = 'BDF     '        (At least I think this works.)

That is: C,A,L,S,T,A,T,space,Equalsign,space,singlequote,B,D,F,space,space,space,space,space,singlequote

(Then you must put your right index finger in your left ear and pat your head with your left hand while reciting:

"Owa Tagoo Siam")

Phil

 

  

    

 

uncalibrated
Ed Wiley_WEY's picture
Ed Wiley_WEY
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Joined: 2010-08-30

Thanks, Phil, and thanks for the email. I guess I am not too concerned unless VPhot calculates errors differently if it thinks the image is uncalibrated. This does not seem to the the case. I will fool with the fits header to see if I can force it. In the meantime, I wonder if Berry and Burnell might think about "fixing" AIP4WIN. I will contast them.

Ed

uncalibrated
spp's picture
spp
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Ed,

Have you been able to get VPhot to process your images?   I was under the impression that VPhot would not process images at all unless VPhot thinks they are calibrated.

Yes, yes, please ask Richard to include this in AIP.  I'll also ask him.  (I believe that Burnell is no longer participating in AIP.)

If anyone else is reading this thread, I'd like to know if MaximDL automatically adds the calibration keyword.

Phil

photometry solving
LuisMartinez's picture
LuisMartinez
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Joined: 2014-06-13

I was about to post a question as to why VPHOT won't solve when I click on VIEW PHOTOMETRY REPORT

but I guess this is the answer? all my images show as red, uncalibrated.

 

luis

Spoke too son, added calstaT
LuisMartinez's picture
LuisMartinez
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Spoke too son, added calstaT bdf to fits header, changed to green, but still get a 0.000 for mag when Iclick on VIEW PHOTOMETRY REPORT.

Vphot pre processing
TCB168's picture
TCB168
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LuisMartinez wrote:

I was about to post a question as to why VPHOT won't solve when I click on VIEW PHOTOMETRY REPORT

but I guess this is the answer? all my images show as red, uncalibrated.

 

luis

Vphot still processes the images even if it thinks they are unprocessed. I preprocess my images with Mira before uploading them and the photometry measurements work with no problems.

Terry

VIEW PHOTOMETRY REPORT
LuisMartinez's picture
LuisMartinez
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Joined: 2014-06-13

thanks terry. Iam a new user trying to generate my first photometry report but all I get are 0.000 under mag.

Images showing as "uncalibrated"
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Richard Berry
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Joined: 2012-06-08

Hi Ed--

I've been meaning to log into the AAVSO discussion group more often. Thanks for bringing this issue to my attention.

As you may have heard, Jim has nor been active in maintaining and updating AIP4Win for several years now. Especially now that Windows XP is defunct, I'm dealing with installation issues spawned by the increase security measures in Windows 7 and Windows 8.

I do understand that VPhot requires a very specific keyword and value in the FITS header before it will accept an image:

CALSTAT = 'BDF     '  / image has been bias, dark, and flat-frame calibrated

AIP4Win users currently have one of three versions: v2.4.0, v2.4.1, and v2.4.8. Versions 2.4.0 and 2.4.1 are official releases, and are essentially identical. We did something trivial like correcting some spelling errors between the two version.

Version 2.4.8 is the current beta release. It's been available to the AIP4Win-Photometry Yahoo group for well over a year. The major difference between it and the official releases is several enhancements to the MMT (Magnitude Measurement Tool) for photometry. It was released as a beta, but it is very stable.

After that beta, I set out to handle DSLR and color images images more fully, and this has resulted in sweeping internal changes in the program. My current working version is v2.4.35. Several DLLs are new, and to handle Win 7 and 8 issues, v2.4.35+ will not be entirely backward compatible with earlier releases. Furthermore, it requires a complete new installation, so it will come from the publisher as an official release rather than as a "beta release" from me.

The net result is that it's not possible to make an incremental change and release only a new executable file, as I had done for many beta trials. Programmers will understand why I am NOT willing to go back to the source code for v2.4.8, make a "tweak" that could easily involve touching the code in twenty places, and release an untested "fix." This type of "tweak" is actually rather invasive, and could easily lead to chaos.

Many programs are capable of calibrating images, so VPhot is effectively asking every one of them to add a novel FITS keyword and value. It would make more sense to change the way VPhot determines whether images are calibrated or not. Perhaps the simplest is a checkbox that overrides checking the CALSTAT keyword and value. This could default to "Check calibration keyword" so minimize the danger of accepting uncalibrated images by accident.

The next official release of AIP4Win through Willmann-Bell will of course support the CALSTAT keyword and value.

--Richard

 

Calibration keyword(s)
Tonisee's picture
Tonisee
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Joined: 2011-06-23

Richard Berry wrote:

Many programs are capable of calibrating images, so VPhot is effectively asking every one of them to add a novel FITS keyword and value. It would make more sense to change the way VPhot determines whether images are calibrated or not. Perhaps the simplest is a checkbox that overrides checking the CALSTAT keyword and value. This could default to "Check calibration keyword" so minimize the danger of accepting uncalibrated images by accident.

I agree, that override at the VPhot upload page could be nicest solution.

From e.g. Iris, i wouldn't get any information about calibrations done. At the same time, IRAF provides quite a detailed information (when using ccdproc task from ccdred package while plain file arithmetics doesn't create any extra keywords):

TRIM    = 'Apr 28 14:01 Trim data section is [1:2048,1:2048]'
OVERSCAN= 'Apr 28 14:01 Overscan section is [2050:2097,1:2048] with mean=1226.3'
ZEROCOR = 'Apr 28 14:01 Zero level correction image is Zero'
DARKCOR = 'Apr 28 14:01 Dark count correction image is mdark60 with scale=0.999'
FLATCOR = 'Apr 28 14:01 Flat field image is FlatI.fits with scale=22309.37'
CCDSEC  = '[1:2048,1:2048]'
CCDPROC = 'Apr 28 14:01 CCD processing done'

 

Yet, both cases are pretty useless in VPhot at the moment... Still, seems that missing preprocessing information doesn't cause any problems when analyzing images.

Tõnis

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