[mmaimcal]Re: reconfiguring

[Min S. Yun]

Hi Gang,

Most of these issues were discussed at some level before, and
it is interesting which idea has survived the test of time.
My recollection as an early participant in this work and as an
ASAC observer is that the reconfiguration cycle time discussed
in the past (at least when the configuration style and reconfiguration
modes were being decided) were shorter. There were discussions of 
going to Y+ configuration only every other times or so, because of the
large overheads in the reconfiguration, etc.  

I don't think the whole ASAC would care to look at all these e-mail
exchanges, but I suspect many members of ASAC have an opinion on 
this.  If someone can put together a straw reconfiguration plan
and a summary of the relevant discussions (e.g. Bolivian winter),
I would like to forward it to the ASAC and hear some of their voices.
What do you think, Al?


					-- Min

-----------

Min S. Yun				e-mail: myun at astro.umass.edu
Assistant Professor			phone:  (413) 545-2215
Astronomy Department			FAX:    (413) 545-4223
University of Massachusetts             http://www.astro.umass.edu/~myun
Amherst, MA 01003



On Fri, 13 Dec 2002, John Conway wrote:

> 
> Hi,
> 
> On Thu, 12 Dec 2002, Al Wootten wrote:
> 
> > I think we all agreed with a cycle of less than a year, so if Fred makes
> > that decision it will be because he had good advice.
> > 
> > Al
> 
> 
> Hi,
> 
> (1)  Yes I think with a cycle time of 9 months you get 
> quite good properties, the time to cycle the seasons
> is 3 years, so 18 months to go to being the  opposite season 
> - but since the compact array and most extended arrays 
> are of order 6 weeks long, the time between the end 
> of one compact array and the start of another is 7.5months
> (similiary for the most extended array), so you get an approximate 
> shift  from day to night observations for your favorite 
> source on the shortest possible timesclale.
> 
> (2) A year can be divided into 8 periods of 6.5 weeks 
> With an exact 9 month schedule, the compact array 
> only every occurs in 4 out of these 8 calendar periods.
> (similary for the most extended array)
> This can be used to advantage if there were periods 
> of order 6.5 weeks long one wanted to avoid for 
> particular arrays.
> 
> If on the other the 
> object is to give every configuration a 'fair shake'
> and sample all parts of the year equally then you would like to advance
> the cycle by about 6.5 weeks over 3 years, so a cycle period of around 41
> weeks would accomplish this. This would ease transporter
> load but it would then be longer between end of a compact array 
> and the start of one (35 weeks) but still give some day/night
> cycling within a single year.
> 
>   John
> 
> 
> 
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