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

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

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

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

URSI Boulder Jan 2006 e-SRT IF Rack

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

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

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

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

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

URSI Boulder Jan 2006 Mapping the local spiral arms

URSI Boulder Jan 2006 HI Column density sky plot

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

URSI Boulder Jan 2006 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