Re: Useful Research?

[Martin Nicholson <Martin@crozet.demon.co.uk>]

>
>>It seems to me that there are four main stages in useful astronomical
>>research.
>>
>>In brief they are:
>>1) Deciding on the project
>>2) Collecting the data
>>3) Processing the data
>>4) Publishing the data in a manner acceptable to the wider astronomical
>>community
>
>This is the way you do it if you are doing sponsored research.  If you ask 
>for money then you have to have a plan and stick to it.  If you are doing 
>things on your own, then you can be an opportunistic adventurer and take 
>big risks and do things just because you can do them.  One might or might 
>not win doing this.  But it is then an individual's choice.
>

If you are self funded I accept that you can do what you like. However
missing out any of the four stages I identified runs the risk of
reducing the value of the research - perhaps even to the point of almost
zero value.




>>I have used the phrase "useful astronomical research" quite deliberately
>>since much time and effort is wasted by amateur astronomers on projects
>>that are rendered pointless when the participants ignore one or more of
>>the basic principles of science. "One variable at a time" is a well
>>established doctrine that astronomers should ignore at their peril.

I didn't make this clear. Suppose you are taking photos of the globular
cluster M3 with a view to looking for variable stars. I claim it would
be better science to keep other variables - such as the exposure time,
filters used or the temperature of the CCD - constant. If lots of
factors are varying at the same time it is difficult to isolate the
effect of each of them individually.

I read recently that CCD obtained magnitude estimates of variable stars
made without the standard filters ( V filter?) in place have a greatly
reduced value. I assume the intention is to eliminate problems due to
the variable response of different CCD's? 

>
>>Calibrating every value on every image against the results obtained for
>>ten or a dozen known non-variable stars that appear on the same exposure
>>might be helpful.
>
>The frames I took last night had 403 calibration stars.  That is 25 per 
>square degree.  This is typical for a sparse field.   There are many more 
>as we go through the Milky Way.

Good, one concern can be crossed off the list.

>
>>I read recently that the vast majority of scientific data is never
>>looked at by those responsible for collecting it. Whatever processing
>>methodology TASS decides to adopt it needs to involve as many people as
>>possible. Too few "data crunchers" can mean that data is coming in
>>faster than it can be processed. The backlog then never gets cleared.
>
>As of last night I had caught up on processing all the data taken since the 
>engineering run became stable last December.  I had last night's rather 
>slim data processed to a star list by 8 AM this morning.  I have now 
>completed the analysis of roughly 18000 images.  I have only had a working 
>analysis pipeline for a few weeks.  While I expect to reprocess all the 
>images again after we make further improvements in the pipeline, the data 
>is good enough to make measurements as indicated by TN-83.

Better still, another concern can be crossed off the list.

>
>>Moving on - suppose we are satisfied that a star is variable. Without
>>accurate information on the position, the period and the amplitude of
>>the variation then this information is hardly worthy of note.
>>Information on a minimum of two complete cycles should be regarded as
>>the qualification for publication. This might take the best part of two
>>years of data collection for long period variables.
>
>I think we disagree here.  The position measurement appear to be good to an 
>arc second which is good enough to match them to more accurate position 
>catalogs like UCAC2.  I think just collecting measurements and making them 
>available in an archive is a useful scientific result.  It is not all the 
>work, but it is some of the work.  So I am content to make 100,000,000 or 
>so photometric measurements on 3,000,000 stars a year from my installation 
>and put them in an archive.  I will attempt to collect a variety of 
>epochs.  There are some that are hard for me.  This is my primary 
>goal.  For amusement on the side I may try to identify and catalog 
>variables.  This is not my primary goal.  I figure that once I get enough 
>measurements in the archive that it will be actively used.  But that is 
>just my bet.

The hard core of active and skilled TASS members will already have known
this excellent news. I, although in TASS terms neither active nor
skilled, love looking through collections of data (we call it data
mining in the United Kingdom) for stars of interest.

The point is - and I made the same point some years ago - that people
outside the hard core might benefit from the creation of a short but
structured summary of what is going on. How is the data collected, how
is it processed, what equipment does a person need to get involved in
data processing etc etc.

I simply would not know where to find out the key facts that might
influence my degree of participation.

For example you write

"I just sent out 26 copies of the data taken between 6 an 8 hrs at +7."

I would like to know:-

1) In what format is the data - list of positions and magnitudes? - I
might have read it somewhere but I honestly don't know what to expect if
I asked for a copy.

2) Readable on a PC using Windows or do I need Unix?

>
>>Once the information is of the required quality and quantity where
>>should it be published so that other astronomers can find it? It seems
>>to me that although most enthusiasts have heard of the GCVS there is
>>still some uncertainty as to exactly how to get information included in
>>the catalogue. There are lots of variable results floating around on any
>>number of web sites that have clearly never been submitted to any third
>>party.
>
>Bohden Paczynski was one of the people who prompted me to do this work.  I 
>just sent him a disk with millions of measurements.  Early on he said that 
>if I took measurements, he would find a way to archive them.  He is now 
>working on it.  Nothing like shoving data at someone to get them away from 
>talking about how to do it and into actual doing.
>

I agree. However the type of person who likes collecting data might not
have the skills to process it and the person who like processing it
might not have the time or inclination to create scientific papers based
on the results.

Martin Nicholson, Daventry, UK

International Astronomical Union's Minor Planet Centre - Observatory Code 456
http://www.gcse-ict.info/astronomy/front.htm