For New List Members

[Tom Droege <tdroege@veriomail.com>]

There is not a big turnover on this list, so most of you probably know what 
is going on.  This message is for newer members of the list for which the 
last several messages must have seemed like pure gibberish.

The Amateur Sky Survey is an informal group interested in making all sky 
photometric measurements of the stars.  Photometric means "how 
bright".  But it means more than that.  It means "how bright" measured in a 
way that is useful to professional astronomers.  The result is that we give 
up on sensitivity in order to measure brightness through calibrated filters.

To do this, I am building a bunch of telescope systems.  These are then 
given away to those that I think might operate them, take good data, and 
process it to a catalog that it useful to astronomers.  This project is not 
funded.  I just buy stuff and try to build telescopes.

The systems consist of a computer controlled mount with two 400 mm f/4 five 
element refractor telescopes.  These have been designed and built to 
optimize the design for accurate photometry.  Each telescope has a 2k x 2k 
CCD camera and electronics to read it out.  Both cameras can be read out in 
46 seconds.  A commercial value for one of these systems is $25,000 to 
$50,000.

Each camera covers a 4 x 4 degree field.  It is possible to take 20 or so 
exposures per hour.  Assuming 80 good nights a year and 6 operating hours a
night (good locations will get more), a system can cover about 60,000 
square degrees a year in two filters.  This is enough to get an average of 
3 measurements on each star in a hemisphere.  If we get a dozen or so 
systems spread north and south, then we can cover all the stars in the sky 
to our sensitivity (about mag 15) 20 or so times a year in each of two filters.

The above is just a possible plan.  There are no rules so different 
operators will alter their programs to optimize what is interesting to 
them.  There will be no directive from above telling us what to do.

I am building telescopes and giving them away for the obvious advantages of 
a standard survey camera design.  Anyone can join in this work.  If you 
have a telescope and a ccd camera and want to work with us, you are 
welcome.  We are a bit technical, and the kitchen gets hot at times. No one 
will tell you what to do.  But if you want to measure stars, then you have 
found a home.  The group will have it's ideas of what constitutes good 
data.  But so will you.  We are working at science, and we will work it out.

The prototype has been working here in Chicago for a year or so, and the 
first two systems have been recently delivered to Flagstaff AZ and 
Rochester, NY.  We should get four more systems out this year.

We hope to start taking real science data this year.

Do not be bashful about making posts to this list.  But don't make stupid 
posts frequently.  This is not a list to discuss relativity, or black 
holes, or to bash astrology.  This is a working list.  We consciously try 
here to expose the process that goes on in any University science 
project.  I find that what goes on in the discussions of this list is 
little different that what goes on at science meetings at Fermilab.  (The 
High Energy Physics laboratory from which I retired).  If you really work 
on this project, you will do the same sort of thing that is done for the 
experimental part of a PhD program.  We have many good advisors who will 
keep you on the right track if you ask for help.  We discuss here the work 
of building telescopes, analyzing data, finding/writing programs to analyze 
data, classifying stars, write papers, etc..   Our home page is at 
http://www.tass-survey.org

Tom  Droege