[Aavso-photometry] Color Photometry

[Chuck Pullen]

Stan - while I fully give you that it is your data to send to  
whomever you want, who sees your data now if it isn't sent to an  
archive?  Who will see it in the future?

I understand your concern, but I doubt anyone does much science with  
the presentations in the Quick View or the light curve generator.   
Anyone who is going to do much will ask for all the data on a given  
object from JD X to JD Y.  Your BVRI data will be there, and obvious  
to them, if that is what they are looking for.

So while our advertising isn't so hot, I wouldn't use that as a  
reason for not contributing to the Int. Data Base.

Chuck Pullen


On Mar 27, 2007, at 9:00 AM, aavso-photometry-request at mira.aavso.org  
wrote:

>
>
> Today's Topics:
>
>    1. Re: color photometry (Stan Walker)
>
>
> ----------------------------------------------------------------------
>
> Message: 1
> Date: Tue, 27 Mar 2007 15:15:09 +1200
> From: "Stan Walker" <astroman at xtra.co.nz>
> Subject: Re: [Aavso-photometry] color photometry
> To: "Michael Koppelman" <lolife at bitstream.net>
> Cc: AAVSO photometry <aavso-photometry at aavso.org>
> Message-ID: <001101c7701e$9aaa4b90$345036d2 at your5139538146>
> Content-Type: text/plain; format=flowed; charset="iso-8859-1";
> 	reply-type=original
>
> Hi Michael,
>
> Recognising that there are sets is the first step in putting the  
> colours
> back together. Still, if a user marked only the UBVRI boxes he'd  
> get some
> idea of what was there. But reassembly is not as easy as it sounds  
> - you
> have to sort to get the matching pairs or sets. I have this  
> experience with
> Doug West's JH listings. If the colour sets are mixed with the odd  
> single
> colour measure, as would usually be the case, it gets rather complex.
>
> As for timing, it's normal to make the measures symmetrically.  
> VBUUBV or
> similar would constitute a set timed at the moment midway in the U  
> readings.
> The number and integration time in each filter is set by the type  
> of target.
> In any case a slightly less than accurate time is not a problem in  
> most
> cases - certainly not with Miras and Cepheids. CVs call for faster  
> work but
> not many people are doing colour photometry of these - it was done
> extensively in the 70s and 80s and the colours behave much the same  
> in most
> cases.
>
> Regards,
> Stan
>
>
>
> ----- Original Message -----
> From: "Michael Koppelman" <lolife at bitstream.net>
> To: "Stan Walker" <astroman at xtra.co.nz>
> Cc: "AAVSO photometry" <aavso-photometry at aavso.org>
> Sent: Saturday, March 24, 2007 4:17 AM
> Subject: Re: [Aavso-photometry] color photometry
>
>
>> Hey, Stan.
>>
>> You know, of course, that a researcher who downloads that data  
>> can  easily
>> put it back in differential form. I totally see the economy of   
>> storing
>> the measurements in individual bandpasses separately. In  almost  
>> every
>> case the individual measurements are taken at a slightly   
>> different JD, as
>> well, so the time window of the differential color  is preserved  
>> if the
>> measurements are stores separately.
>>
>> I guess I don't see why this would cause you to withhold your
>> observations.
>>
>> Best,
>> M.
>>
>> PS - This was sitting unsent in my mail app. I hope I didn't send it
>> twice!
>>
>>
>> On Mar 15, 2007, at 4:05 PM, Stan Walker wrote:
>>
>>> At present I do not contribute data to the AAVSO for a different   
>>> reason.
>>> I
>>> have mentioned to Arne my concerns at the way the database is   
>>> arranged.
>>> The
>>> Star of the Season - RR Tauri - illustrates this point. In his  
>>> article
>>> Laszlo Kiss discussed the colour changes of this star when  
>>> mentioning
>>> 'blueing' and photometric measures. But if I send in UBV  
>>> measures  of RR
>>> Tauri (which can be observed from NZ) my V, B-V, U-B colour data   
>>> will be
>>> separated into separate V B and U curves which are not nearly so
>>> informative. In this area the historical methods of the AAVSO   
>>> hinder the
>>> natural progress of something like colour photometry. One of his   
>>> themes
>>> was
>>> that by using a wide range of disciplines visual, pep, nir,   
>>> polarimetry,
>>> spectroscopy, you get a fuller picture. So this is one area  
>>> where  change
>>> would be helpful.
>>
>
>
>
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> End of Aavso-photometry Digest, Vol 40, Issue 33
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