Lots of software and software-engineering discussion in this blog today.
Reed Riddle's Talk
Reed gave a nice talk about robotic astronomy. The key point is an essential
one. It requires deep though to design something that is efficent,
maintainable, and flexible. It is challenging to make a system behave well.
Software often grows organically, sometimes organic growth works. Reed argues
that best performance comes from good design -- though this is never
demonstrated. The talk was architected to demonstrate both sides of the coin,
first with TMT second with robo ao.
TMT Site Testing
Pre-selection of five candidate sites based on satellite studies of cloud cover
and water vapor. Used identical equipment with emphasis on proper
- TMT Candidate sites:
- Tolar, Armazones [VLT], Tolonchar, San Pedro, and Maunea Kea.
Out of a suite of 12 instruments there was one seeing monitor and then some
kind of turbulence or environmental monitor. The sites are environmentally
tough so software has to be robust. The site-testing software was significant
with 7 operating systems plus 12 scripting and programming languages. All of
this grew organically.
The organic growth meant that there was no way to design the system. As a
result, the operations were sequential requiring blocked state. But as a result
there was no coordination between the instruments and efficiency is low with
something like 30% science time. It was also to difficult to maintain this
Learned that there is no single right way to create a system. Early design
decision affect the operational efficiency. No initial planning for software.
It was hard to find time to make the system robust. Ultimate lesson: temporary
fixes become permanent fixtures. Perfect is the enemy of good enough.
Fully automatic adaptive-optics system. Lots of good details at the robo-ao
website. End result is that seeing-limited images of 1" are converted into
fraction-of-an-arcsecond images produced by Robo AO.
'Half the resolving power of HST at less than a ten-thousandths of the cost'
Robotic ao operations usually require a large staff. The vis AO at magellan has
a team of engineers and staff monitoring the AO system.
Robo-ao uses a modula control software syste. Robotic system, watchdog, system
monitor, data system, and status system. Each subsystem is a demon and the
demon has inherited a variety of code from one and other.
Performance of robo-ao is impressive! Over half the observing time is science