SARA Conference 2017 20 Meter Dish Demo

20 Meter Dish Demo NRAO Conference Account - Explore! Skynet Account (free UNC Course) - Your Personal Account! Demo Example – Watch the dish move outside! SARA Analytical Section Observing Program SARA Section Open Forum

20 Meter Dish Demo Add a Radio Observation -Select an Object (Database or RA/Dec) -Minimum Elevation (Used for mapping) -Solar Separation (to prevent solar side lobe interference)

20 Meter Dish Demo Configure Receiver Low Resolution: continuum mapping/pulsars High Resolution: Spectral Lines No Filter Full Band (with interference) H1 Filter (continuum maps, 1355-1455 MHz) OH Filter (Iridium sat. interference, 1.6- 1.73 GHz)

Choose Path Setting Track On/ Off Daisy Map (Raster) 20 Meter Dish Demo Choose Path Setting Track On/ Off Daisy Map (Raster)

Output (Track) : Molecular Cloud W51 20 Meter Dish Demo Output (Track) : Molecular Cloud W51 Shows the average spectra averaged over all integrations. The upper and lower plots are for the two frequency bands and the two traces in each plot are for the two polarizations. Shows the continuum. This is the average of the central 80% of each spectrum pattern vs time. The four traces are two polarizations and two frequency bands.

20 Meter Dish Demo Output (On/Off): 3C279

Output (Daisy): Cassiopeia A 20 Meter Dish Demo Output (Daisy): Cassiopeia A The color wedge on the right represents the intensity of the source in Kelvins, not the physical temperature of the object but rather the increase in temperature the telescope feels when pointed at the source. Sharp peaks of intensity correspond to the telescope pointing directly at the source which is at the center of the daisy pattern.

20 Meter Dish Demo Output (Map): Cygnus A

SARA Sections Observation Program Development of an Observation Program 1. Types of Observations 2. Targets 3. Pre-Optimization of Observations 4. Output and Data Processing - Raw data - Raw Data processing 5. Interpretation of Data 6. Quality control 7. Goals - Database - Citizen Science

SARA Sections Observation Program Types of Observations Continuum Mode Spectral Mode (H, OH, etc.) Skynet Pulsar Mode Frequency Range (L-Band, X-Band, etc.) Track, On-Off, Daisy, Mapping Counts, Kelvins, Janskys Astronomical League’s Observing Program Effects (Doppler, Noise, Variability, Interference) Popular Radio Telescope Observing (INSPIRE, SuperSID, Radio Jove, Radio Meteors, IBT) Popular Book Observing Experiments

SARA Sections Observation Program Targets 1. List of Brightest Celestial Radio Objects 2. Sun, Moon, Planets (Jupiter), Radio Meteors 3. Satellites 4. Neutral Hydrogen 5. Masers 6. Pulsars 7. Supernovae 8. Radio Occultations

SARA Sections Observation Program Maser OH808-19 Maser – Microwave Amplification by Stimulated Emission of Radiation. OH/IR Stars: 1612 MHz, 1667 Late stages of asymptotic giant branch stars develop a super wind with extreme mass loss. Gas in the wind condenses OH radicals produced by photo-dissociation or collisional dissociation.

SARA Sections Observation Program The Sun

SARA Sections Observation Program Pre-Optimization of Observations (20 m dish) Track Set to 60 seconds for galactic hydrogen and strong pulsars On-Off Offset to a few beamwidths or 3-4 degrees Durations generally larger than optical: Use 30 to 60 seconds For hydrogen in nearby galaxies 200-300 seconds For 1.4 GHz receiver Daisy maps should have radius of 2 degrees or more Set radius to 120-180 arcmin. (3-4 beamwidths); 4 petals quick look. 0.1 – 0.2 sec integration time Raster maps no smaller than 3.5x3.5 degrees; or 6x6 beamwidths Use ¼ or 1/3 beamwidth for quick maps; 1/5 or 1/10 for detailed Map depth: time in integration is the time corresponding to the gap along the sweeps, and it will calculate the slew speed.

SARA Sections Observation Program Output and Data Processing Screens Output screen provided (Skynet 20 m dish) Widely available output screens (Radio SkyPipes, GNU Radio) User programmed output screens (Python – Princeton 18 m) Audio Paper Strip Chart Units Photon Counts Kelvins Janskys

SARA Sections Observation Program Data Processing Low resolution mode provides 1024 spectral channels in a 500 MHz band. The channel spacing is 0.488 MHz High resolution mode allows the number of channels to be selected.

SARA Sections Observation Program Data Processing When the 20m telescope observes an object it is recording data 10x a second. Time, position, and the amount of counts received by both polarizations of the telescope are recorded.

SARA Sections Observation Program Interpretation of Data Manuals and papers Cross comparisons Resolution Expectations (Can the target be resolved?) Repeating Observations by adjusting input parameters

SARA Sections Observation Program Quality Control Select correct type of observation -Track: Good for spectra in high resolution & pulsars -On-Off: Compares to a reference & good for fainter spectral lines -Daisy: Petal pattern maps for preliminary observations -Map: Back & forth detailed scans (wide band continuum observations)

SARA Sections Observation Program Quality Control Consult Manuals if available Interference Doppler Galactic hydrogen and arms Internal instrumentation noise On-Off Techniques Calibration Solar temperature effects Ground/building reflections, sky blockage, side lobes Secondary frequency: comparisons, problem identification Band width & other parameters chosen Ubiquitous neutral hydrogen

SARA Sections Observation Program Goals Database Raw data - Calibrated - Raw ASCII - Continuum Data (ASCII) - Spectrum Data (ASCII) Raw data processing Data Collection Citizen Science