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The Iowa e-SRT laboratory

The Iowa e-SRT laboratory. Robert Mutel, Laura Spitler * , Kevin Ivarsen † University of Iowa. * Now at MPI, Bonn † Now at UNC. Summary. Astronomical lab course Mostly junior/senior undergrads 1/3 each: data analysis, optical labs, radio labs Optical half uses Iowa Robotic Observatory

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The Iowa e-SRT laboratory

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  1. The Iowa e-SRT laboratory Robert Mutel, Laura Spitler*, Kevin Ivarsen† University of Iowa * Now at MPI, Bonn † Now at UNC URSI Boulder Jan 2006

  2. Summary • Astronomical lab course • Mostly junior/senior undergrads • 1/3 each: data analysis, optical labs, radio labs • Optical half uses Iowa Robotic Observatory • Radio half used modified Haystack SRT (‘e-SRT’) • Also teach ‘science-based’ radio astronomy course • e-SRT • Hardware modifications • Optical encoders added • Digital receiver replaced with ‘traditional’ super-heterodyne receiver • Spectrometer replaced with 1024 channel autocorrelation receiver (USB interface) • Software modifications • JAVA-based Haystack system replaced with Python modules • Spectrometer control uses C • Curriculum examples URSI Boulder Jan 2006

  3. Iowa Robotic Observatory(located 50 mi SE Tucson AZ) URSI Boulder Jan 2006

  4. Radio astronomy labs:LC filter Filter ‘Lite’ Program URSI Boulder Jan 2006

  5. e-SRT Telescope modifications • Elevation axis • inclinometer (±0.1° resolution) • Serial interface • ~ $100 • Azimuth axis • 10-bit absolute encoder (US Digital) • ~ $200 URSI Boulder Jan 2006

  6. e-SRT receiver system I: Front-end Box URSI Boulder Jan 2006

  7. e-SRT Receiver II: IF Rack URSI Boulder Jan 2006

  8. e-SRT IF Rack URSI Boulder Jan 2006

  9. e-SRT III: 1024 channel auto-correlator • Uses ‘quaint’ CMOS correlator (UNM 1993, also used at GBT) • 1024 lags, 2 or 3-level, 100 Ms/s max. • e-srt mode: • 4Ms/s (2 MHz = 422 km/s range) • N x 0.523 sec integrations • Output I/O either PCI or USB • Correlator software written in C • Still in development • Overheats unless reset pulse applied on power-up • Occasional random failures • USB interface not complete URSI Boulder Jan 2006

  10. e-SRT Telescope control software • Written in Python 2.3 (with WX-Python for GUI) • Runs on Linux/Windows/Mac • More flexible control of telescope • (Probably) easier to modify on-site • Correlator control software currently in C (port to Python in progress). May not be portable. URSI Boulder Jan 2006

  11. e-SRT software: Scripting and web-scheduled operations URSI Boulder Jan 2006

  12. Lab project write-ups (available on web) URSI Boulder Jan 2006

  13. e-SRT observational projects I: Spillover temperature and telescope beamwidth using Sun FWHM = 5.1°± 0.1° URSI Boulder Jan 2006

  14. e-SRT observational projects II: Mapping HI 21cm emission along galactic plane URSI Boulder Jan 2006

  15. HI 21 cm longitude-velocity plot along galactic plane URSI Boulder Jan 2006

  16. Mapping the local spiral arms URSI Boulder Jan 2006

  17. HI Column density sky plot URSI Boulder Jan 2006

  18. Finale: Field trip to North Liberty Iowa VLBA site! e-SRT to scale URSI Boulder Jan 2006

  19. Summary • Goal: redesign SRT to more closely emulate ‘standard’ radio telescope • SRT modifications: • Telescope: optical encoders for better positioning (no homing needed) • Receiver: replace with super-heterodyne, • Add many test points, 50 ohm load, test signal injection • Correlator: replaced with 1024-channel autocorrelator • Faster than SRT receiver (all 1024 channels available) • Software: Replaced JAVA code with Wx-python • more modular, • also transportable, • added user features URSI Boulder Jan 2006

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