How this all started.

[Tom Droege <tdroege@veriomail.com>]

Michael may remember that shortly after Shoemaker-Levey crashed into 
Jupiter I posted to sci.astro "Would an all the sky all the time survey to 
mag 15 be useful?"  Michael answered back "Yes!" , and I have been trying 
to do it ever since.  Now he says that Mag 12 is OK.  ;^)

I a quite happy to go where the science is.  I suppose one could cover more 
fields with the present program by moving up and down in 
Declination.  Start tracking a field, take 4 declinations, take them again 
while still following, ... for 3 or so hours.  I can't do this with TOM1, 
but could with TOM2 and TOM3.  This would get 10 or so measurements spaced 
over 3 hours for the fields measured.

The same could be done while getting the flat field data to cover more area 
with single exposures.

Would this be a better program?

I keep getting the impression that it offends astronomers to not look at a 
specific spot in the sky.  I figure that for a survey, one piece of sky is 
as good as another.  One just needs a strategy that eventually gets everything.

Yep, I am definitely more a marathon runner than a sprinter.  Still, I am 
71 years old, and need to start reducing data if I am ever to publish.  As 
I recall, the original marathon runner died as he crossed the finish 
line.  ;^)  I would like to get something done before then.

Tom Droege

At 03:48 PM 10/17/01 -0400, you wrote:


>   Tom said:
>
> >  If we don't go as deep as we can, then we run the risk of
> >  only measuring previously well studied objects.
>
>   Arne wrote:
>
> > ... So you have to look at what is unique about the Mark IV and
> > make the uniqueness work for you.
> > In my mind (and I've told Tom this before), the unique aspects
> > are the simultaneous V&I exposures and better angular resolution. ...
>
>   <soapbox>
>
>   I agree 100% with Arne: the Mark IV _can_ do "real science"
>even at mag 12, or mag 10.  Yes, (almost) every object which is
>mag 12 has been seen and recorded before by someone --- BUT
>so what?  In (almost) every case, the recorded and catalogued
>measurements are
>
>           a) years old
>           b) a very few epochs
>           c) taken only in the V-band, or the "photographic" passband
>
>   What we _don't_ have is a set of accurate and precise photometric
>measurements, at the 3-5 percent level, of thousands of stars in
>the V-band and the I-band.  Nor do we have knowledge of the variability
>of all these stars.  And, and, in just a FEW cases (say, 1 in 10 million),
>we don't even have accurate positions, because the stars are moving
>_so_ fast that they move an arcsecond every year, and matching up
>such extremely fast-moving stars on different plates taken years
>apart is really hard (Arne knows a lot more about this particular
>item than I do, of course, and I hope he'll correct me if I'm way
>off here.   But I do think that is the possibility to catch the
>one-in-10-million or 1-in-100-million shot here).
>
>   Anyway, I second Arne's claim that repeated observations of
>even bright stars -- with proper photometric calibration -- is something
>rare in astronomy.  Most astronomers don't have five years to make
>a proper study of such things: they have to produce a result in
>six months, in time to write the next grant proposal.  TASS members
>can beat (most of) the pros at this game, no problem.
>
>   Arne mentions ROTSE, for example.  The ROTSE team use a robotic
>telescope with a scad of CCDs to measure stars in a huge field,
>16-degrees on a side.  Their primary goal is to find optical
>counterparts to gamma-ray bursts, and they have done so for
>exactly one GRB.  They also measure stars, on the side, as it were.
>You can read their first paper describing their stellar measurements
>in ApJ, April 2000, vol 119, p. 1901, or at
>
>  http://www.journals.uchicago.edu/AJ/journal/issues/v119n4/990545/990545.html
>
>   Now, they present an impressive number of observations in this
>paper.  Note the following sentence:
>
>         "... Photometric calibration is somewhat more complex.
>          The Tycho catalog includes only B and V photometry,
>          and ROTSE-I images are obtained with unfiltered CCDs ..."
>
>   Yes, they do find a lot of variable stars.  That is good, and in now
>way do I wish to demean their work.  But, if one wants to know more
>about any particular system, one may be stuck: there is no measurement
>in a standard passband (such as B, V or I), and there is also no
>indication of stellar color (and hence temperature).
>
>   Should we throw up our hands and say, "Gosh, what's the point,
>ROTSE has already seen all the variable stars"?  I reply, "No."
>
>   Oh, in addition, you might note that they have published the analysis
>for stars in only 9 of their 160 patrol fields across the sky.
>
>   Anyway, please don't give up hope that "we can't do any good science
>without pushing the limits."  Other people are going to beat us
>to any particular limit --- but few will be able to stay the course
>in the long term.  I look at TASS as a marathon runner: not as fast
>as a sprinter, but longer lasting.
>
>   </soapbox>
>                                                   Michael Richmond
>
>
>
>