[Aavso-photometry] Chart id's

[Aaron Price]

 The copyright on the chart is going to be replaced with a date. The main 
reason for the system is so that researchers can get easy access to the charts 
used by the observers. Right now it is a very difficult and time consuming process 
that requires the researchers to contact HQ, HQ to contact the observer (sometimes 
because the chart ID they submitted is vague), HQ to look up the chart and e-mail 
it back to the researcher. Now, anyone can see any chart *exactly* as the observer 
saw it by just typing in the Chart ID (or clicking on the link in the Quick Look 
file). The Chart ID also allows us to eventually reach the age-old dream of having 
a system that checks to see if someone is using an old chart and automatically 
e-mailing them if the chart has been updated. We've been talking about that for almost 
ten years now. Finally the infrastructure is now in place to do it, we just need 
to code it - that's the easy part. 
 We struggled with using the date as the base index of the system and debated it 
internally. The decision was made to use the chart database version as the index 
because it is shorter than the date. In order to use the date and remain unique, we 
would need to code the date down to the second - which was making for extremely 
long Chart IDs. Even if we used digits for the YYMMDD and the the alphabetic base for 
the hours, minutes and seconds we were running into 12 digit Chart IDs that were 
ugly: 080720aabdjapq. That is just inviting user error. We will put the date in the 
copyright field. That will be done very soon, we're waiting on someone to return from 
vacation. But the date should become less important as the tool goes online to automatically 
tell you if your sequence is out of date.
 Note that this system is not neccessarily easier for IT staff. The Chart ID program 
is one of the most complicated programs I have written and was quite frustrating at times. 
It would have been easier to just leave things as-is. But I do love the capabaility 
we now have. 

Aaron


On Mon, Jul 21, 2008 at 07:52:24AM -0700, Kate Hutton wrote:
> Wheww ... this system may be easier for the IT staff & I'm sure it is, but
> the user/observer now lacks a basic & intuitive piece of information ... how
> old is the chart I'm using?  Does not using the date as a chart identifier
> uniquely determine the sequence?  Guess I don't really understand the reason
> for this change.
> 
> Kate HTN
> 
> On Mon, Jul 21, 2008 at 7:32 AM, Aaron Price <aaronp at aavso.org> wrote:
> 
> > > This id changes every time you reload the webpage. It appears to
> > > increment. Why so? Are they keeping a record of every request to the
> > database?
> >
> > Yes it is keeping a record of every request. That is because every request
> > can be different.
> > You can change the field of view a tiny bit, tweak the limiting magnitude,
> > etc. Remember we
> > don't have "set" sequences and charts now. What we have is a database of
> > comparison and field
> > stars with dynamic sequences and fields that change based upon the user's
> > specifications. With
> > a unique chart ID, we can recreate the chart and/or sequence that you used.
> > For some more info
> > on how we are doing this read these earlier posts to AAVSO-Discussion:
> >
> > http://mira.aavso.org/pipermail/aavso-discussion/2008-July/014439.html
> > http://mira.aavso.org/pipermail/aavso-discussion/2008-July/014471.html
> >
> > Aaron
> > _______________________________________________
> >
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> >

-- 

Aaron Price
Technical Assistant, Technology
American Association of Variable Star Observers
www.aavso.org