[mmaimcal]Meeting

[Bryan Butler]

i would guess that we might not want to sit in the full resolution Y+
for a full 2 months.  cut that in half, perhaps.  just a thought.
unfortunately, that doesn't solve the problem, since you only gain
4 weeks per year from that.

i would attempt to up the number of moves per week, probably.  how
about 10 moves per week (3 each on M/W/F, and 1 extra one, whichever
day allows it [i.e., if it's OK on monday, do it]).  this buys you
an extra 25% on the marching.  this, along with the decreased time
in the full Y+, might save you enough to cycle through sensibly
(my rough numbers provide: 7.5 weeks COMPACT; 14.5 weeks march OUT;
3.5 weeks Y+; 14.5 weeks march IN = 40 weeks.).  hmmm.  as mark
points out, this is a 3 year cycle to go through seasons...  going
to 12 moves per week, which is 4 per day on M/W/F gives you a total
move time of 35 weeks, which gives you seasonal cycling in a 2 year
timescale - that might be quick enough.

how many intermediates are there between the outermost conway config
(4 or 5 km max baseline) and the full Y+?  we've discussed before
skipping those intermediates.  how much time is saved if you do that?


	-bryan


On 2002.12.10 15:13 Mark Holdaway wrote:
> 
> 
> Folks,
> 
> With 4 moves per day made 2 days per week, it takes about 18 weeks to go
> from COMPACT to Y+.  Making an assumption about how long you sit in the Y+
> and COMPACT arrays (15% in COMPACT, 15% in Y+),
> 
> we end up with something like:
> 
> 	7.5 weeks	COMPACT (including N-S extension)
> 	18 weeks	march OUT
> 	7.5 weeks	Y+ config
> 	18 weeks 	march IN
> ---------------------
>         51 weeks
> 
> 
> Which, at first thought, is great (ie, drink vodka for a week and we've
> got 52 weeks even), but on second thought, is BAD.
> 
> We want the arrays to cycle through the time of year.  When we MARCH
> through the intermediate arrays, we'll hit them in SPRING and FALL, or
> in WINTER and SUMMER.  It isn't quite that simple because small
> intermediate arrays will aloways be close to the compact array and will
> not be 6 months apart.  BUT, we'd like to cycle through the seasons
> in a different way, so that EVERY configuration gets to see EVERY
> source with good TAU and PHASE STABILITY sooner or later.
> 
> 
> Questions:  1) What about the assumptions of 15% of the time in Y+ and in
> 	Compact?  If these go down to 5%, the whole cycle is like 40
> 	weeks, so we cycle through the seasons roughly every 3 years.
> 	I DISAGREE WITH THIS ONE.
> 
> 	2) If we sit in Y+, Compact for LONGER, ie, 22% each, we get
> 	something like a 1.25 year configuration cycle, which will
> 	cycle through in 5 years (similar to VLA, which is 4 years).
> 	I AM GUESSING THIS IS TOO LONG, BUT COULD BE RIGHT.
> 
> 	3) Other options include moving antennas 3 days a week or
> 	   3 days every 2 weeks to speed up or slow down the cycling;
> 	WHAT DO YOU GUYS THINK? 
> 
> 	4) Or do like the VLA and MARCH the antennas one way as fast
> 	   as you can, skipping stations, to get from say COMPACT to Y+
> 	   FAST, and going liesurely the other way. 
>  	   But I believe this goes against the ideas we've gone
> 	   along with in the past:  smooth reconfigurability.
> 	I AM AGAINST THIS IDEA, BUT FOR NO GREAT REASONS.
> 
> Ultimately, observing pressure (perhaps with administrative nudges) will
> decide exactly what happens here, but it would be good to find a scheme
> that both matches observing pressure and fits nicely with our desire
> for cycling around the seasons (ie, is consistently either a fair bit
> SHORTER or LONGER than 1 year even).
> 
> 
> I'M JUST LOOKING FOR OPINIONS RIGHT NOW.
> 
> 
> Take care,
> 
>     -Mark
> 
> 
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