Re: Fwd: [Aavso-photometry] pipeline

[Thomas Droege <tdroege2@earthlink.net>]

Fraser,

Some interesting ideas.  I assure you I am not trying to take "bad" data. 
I just don't know what makes some data better than others or even how to
select "good" data from bad.

> The (naive) test for this hypothesis is to compare your I data from
> the 2001 "no flying" period with your recent I data of the same
> starfields.
>

All the data is there for anyone interested to try such an experiment.  I
will shout encouragement to anyone who tries any such thing.

Tom 


> [Original Message]
> From: Fraser Farrell <fraser@trilobytes.com.au>
> To: tass <tass@listserv.wwa.com>
> Date: 1/3/2004 6:25:28 PM
> Subject: Re: Fwd: [Aavso-photometry] pipeline
>
> On Fri, 2 Jan 2004, Thomas Droege wrote:
> >The solution is to take as much data as possible with as much information
> >as possible as to how the data was taken.  Then as time goes on and the
> >data is studied, then it might be possible to sort out the things that
are
> >important for taking good data.  Then it will be possible to select the
> >good data.
> >
> >At the moment, I have very little indication as to what will make good
> >data.  I am particularly suspicious of the I data since I think things
are
> >going on in the sky that causes big problems with the I data.
>
>
>
> Tom,
>
> Scientific history is full of bad data that turn out to be useful
> after all. Possibly in another context. So keep on taking those images
> and archiving them.
>
> The example most readily to mind is observations of ancient eclipses;
> where a typical report reads something like "During the 9th year of
> the reign of King Aarrgh, the sun turned black and stars were seen
> over the city in the daytime". By modern data-collecting standards
> this observation is "bad" (no timing of totality, no images, etc) but
> nonetheless it can be used to investigate topics such as:
>
>  - the Earth's rotation rate, and associated geophysical phenomena
>
>  - secular accelerations in the Earth-Moon system
>
>  - and of course the actual dates of King Aarrgh's birth/reign/death,
> and associated events.
>
> I doubt that the ancient scribes and historians would have considered
> the data-collecting standards needed for the first two topics. But
> note that they didn't need atomic clocks and lunar laser reflectors
> to produce a useful data point anyway!
>
>
>
> As for your I data, I wonder if aircraft contrails, not necessarily
> visible to the eye, are affecting it? I recently read a climate report
> describing a small but consistent drop in air temperatures, over the
> continental US, during the last quarter of 2001. The authors
> attributed the cooling to the grounding of commercial aviation at the
> time, and the consequent -absence- of the usual aircraft contrails
> that reflected outgoing heat back to the ground. I note that from your
> location you're probably looking through some rather busy flight
> corridors?
>
> The (naive) test for this hypothesis is to compare your I data from
> the 2001 "no flying" period with your recent I data of the same
> starfields.
>
>
>
> cheers,
>
>
> Fraser Farrell
>
> ----------------------------------
> http://astronomy.trilobytes.com.au
> ----------------------------------
>
>