1. 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

2. 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

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

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

5. 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

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

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

8. URSI Boulder Jan 2006 e-SRT IF Rack

9. 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 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

10. 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.

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

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

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

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

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

16. URSI Boulder Jan 2006 Mapping the local spiral arms

17. URSI Boulder Jan 2006 HI Column density sky plot

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

19. 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