The ALMA Observation Support Tool Adam Avison UK ALMA Regional Centre Node
Overview • • Introduction to the OST Breaking the 4 th wall Simulation inputs Breaking the 4 th wall (reprise) Output to users ALMA cycle 0: An Education ALMA cycle 0: How things went
ALMA: A very brief introduction • When in full operation ALMA will consist of 66 dishes operating between ~90 GHz and ~1 THz, on the Chajnantor plateau, Chile. • Full operation is expected sometime in 2013. • As of 10 days ago ALMA began Cycle 0 observations with ~16 dishes.
ALMA Observation Support Tool • The OST is a web based ALMA simulator. Accessible from any standard web browser. • Designed for those who are not interferometry experts. • Written by Ian Heywood (Oxford). • http: //almaost. jb. man. ac. uk
USER @ HOME/OFFICE Browser + e-mail Client INPUT WEBFORM OST @ MANCHESTER Python/CASA backend OST WORKFLOW SUBMISSION NOTIFICATION inc. Live. Validation SERVER SIDE CHECKS ADAM @ REST USER’S EMAIL SIMULATION OUTPUT WEBPAGE SIMULATION COMPLETE! OST ADMIN
Breaking the 4 th wall - OST simulation of under illuminated Lunar surface
User Input. • • • Array: Selects the array configuration. Currently has the two Cycle 0 configurations, the ACA and one called ALMA*. Sky Setup: • Source Model. Can select from OST library or user Uploaded FITS file. • Declination==Declination • Image peak For rescaling input image peak value. Observation Setup: Standard observing characteristics e. g. Frequency, BW, resolution*, etc.
User Input. • Corruption: User can select from 3 PWV values. Good, Bad or Ugly. Behind the scenes: Noise is calculated using eqn 1. Comparison to simdata fairly good. • • Imaging: Standard interferometric parameters. Image Weighting, CLEAN application and output file format (FITS or MS). E-mail Address: Possibly the most important parameter.
Breaking the 4 th wall (reprise) - OST Simulation of ‘Super’ M 4 R 10 Galaxy
Cycle 0: The results • Over the ~95 Day call period 2064 jobs we submitted and completed successfully. Excluding IH and AA == 1846 by users. • 19. 4 jobs per day (average). • 261 jobs caught in Live. Validation or server side checks. • ~60 jobs for unique users caused the OST to fail. With only 6 remaining unresolved at the end of call*. Daily OST usage: Solid blue line total number of successfully completed submissions. Dashed purple line total minus testing by OST admin. Solid Orange seven day running average. Vertical green denotes Cycle 0 proposal call, vertical red Cycle 0 deadline, vertical black separates months • Mostly FITS file issues see later slide.
Cycle 0: The results • OST seems to have been well received internationally. A fun, though erroneous, statistic would be there are ~2 OST submission per Cycle 0 proposal submitted : D. • The largest number of jobs came from the UK, then from the. com TLD (which is tricky to pin down). • The largest number of unique users use the. com TLD followed by. uk and. jp. • Both figures exclude AA and IH
Cycle 0: An Education • FITS Headers: ‘Flexible Image Transport System’ or ‘Frustration Incarnate, Telephone Samaritans’. – 3 methods (at least) of defining WCS. – BITPIX values. (GIMP!) – Rotation, currently not handled by OST. • Expect the unexpected: … and don’t expect all submitted jobs to make sense! Future upgrades: – – – Separate Hour Angle coverage. Rotation handling. Bigger library. Some behind the scenes bits (mostly already done!). Enhanced mosaicking capability.
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