[mmaimcal]Re: reconfiguring

[John Conway]

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