NAIC AUSAC Meeting – April 19-20, 2010 Pointing Date Az Err (arcsec) Za Err (arcsec) Total Err (arcsec) 2003 mod mod mod Jul08-feb Mar09-jan Mar10-> Pointing model made dec07/jan08 after painting shutdown.
NAIC AUSAC Meeting – April 19-20, 2010 Mar09-jan10 data before break –Errs vs za –Errs vs az (1 az term y08-09 removed in model) Mar10: after beam repair: –Errs vs za (limits: 3.5 to 12 deg za) –Errs vs az (looks like 1az term..) RmsError: –Before break: 4.9,6.3 (za,az). Tot: 8.0 asecs –After break: 9.0, 10.6 (za,az). Tot:13.9 asecs Pointing Errors: mar09-mar10
NAIC AUSAC Meeting – April 19-20, 2010 Gain,SEFD,Tsys:lband,cband Data mar09 - mar Mhz 5000 Mhz Gain Tsys Sefd Beam width Lband 1400 Cband 5000 Gain K/Jy Tsys K28 K27 K SEFD2.5 Jy3.3 Jy bmWidth202”56”
NAIC AUSAC Meeting – April 19-20, Mhz rcvr Installed jul to dec09. penn state feed –Cooled to 70K, cavity filter in front of lna. –Gain,Tsys: Tsys high.. Cavity filter, over illuminates tertiary. –Sefd,BeamWidth –Rfi: Chn 67 (879 Mhz) LP tv. Helped buy parts for lp dtv so they would go off the air BYU single pol rcvr 5% smaller bm width –Still working on dual pol mode. Running out of time for clean band: –Emg services: , ready to go.
NAIC AUSAC Meeting – April 19-20, 2010 Alfa Alfa tsys measured during survey runs: –4048 measurements mar09 thru mar10. –Each color is a different project: White:A2010 (alfalfa), Red:A2048(ages), Green:A2433(auds), Blue:(A2453) –PolA on left, polB on right. –Beams 0-3 –Beams 4-6 –Beam 2a has unstable Tsys.
NAIC AUSAC Meeting – April 19-20, 2010 observing limitations The weights and distances on az arm. –Za for dome center of mass: 1.9deg below optic axis za –Ratio DomeWeight/ChWeight = 6. For constant moment arm: dzaCh = 6*dzaDome. How we observe: –Ch sits at 8.8 degrees, dome moves in za. –Azarm imbalance changes with dome za. –Elevation rails shimmed high so imbalance tilts receiver in dome, onto the paraxial surface. –3 tiedowns keep the average platform height fixed with temperature (no tilting of platform done by td’s)
NAIC AUSAC Meeting – April 19-20, 2010 The problem: Max allowed imbalance:15000 kip-ft –Various configs for ch, dome motion: BUT: max allowed imbalance depends on td tension –Td tension relieves tension in beams. Td tension used to keep avg platform height in focus. –This is a function of temperature since main cables change length with temp. Examples showing za range vs temp: –Dome tracks: Ch at stow: normal astronomy –Dome tracks: Ch tracks dome above 8.8 deg za –Dome tracks: Ch at 0 (aeronomy az swings).
NAIC AUSAC Meeting – April 19-20, 2010 What we can do: Removing weight from the dome –decreases the unbalanced moment arm Removing weight from the platform – Allows more tension in the tiedowns Installing the tertiary motor drives. –Lets you make the optical axis longer –This lets you increase the td tension (pull down on platform) to get back in focus. 1 platform inch is 2-3 kips per corner 1 deg F is.75 kips per corner.
NAIC AUSAC Meeting – April 19-20, 2010 Datataking:new functionality Mock single pixel observing –7x172Mhz covers 1Ghz IF with 20Khz res. 1 Ghz, 10Khz res. Possible with 2 nd 7x172 set –Different settings allowed for 7 bands: Center freq, channels, bw, config:sumPols, 2pol, stokes. Mock file server upgrade: –3.2 -> 5.5 Tb/server. TotalDisk:14*5.5=70 Tb online. Mock aeronomy sampling system –6 bands: 32Mhz widest, –Example:10 sec clp spectra (ch)
NAIC AUSAC Meeting – April 19-20, 2010 Alfalfa extragalactic search, short integrations, large area Ages – extragalactic search, median integration Auds – extra galactic search: long integration Zoa : zone of avoidance Galfacts: galactic polarization survey Rrl: recombination line survey Togs- galactic survey Palfa: pulsar search. Datataking:Commensal PrimaryCom1Com2 alfalfa/wappTogs/galspectPalfa/mock1* Ages/mock1Togs/galspect Palfa/mock1Zoa,rrl/mock2 Galfacts/mock1Zoa/mock2 Igalfa/galspectGalfacts/mock1Zoa/rrl/mock2 Survey names: Routine survey commensal observing: Example: Igalfa/galfacts/zoa,rrl: may09-sep hour sessions Igalfa- galactic survey galspect, Galfacts: mock,full stokes, 300 Mhz Bw. 65Mb/sec *7 =455 Mb/sec, 4Tb/night Zoa/rrl:mock2, 300 Mhz Bw,.1 sec integrations.
NAIC AUSAC Meeting – April 19-20, 2010 Future:Backends Vlbi: Digital BackEnd: dbe –2: 1 for 305meter, 1 for 12 meter –Has mode to run 500 Mhz bw spectra Aeronomy –Integrate mock device with datataking. Planetary radar with mock: –Needs fgpa programming (or use regular baseband sampling with pdev).
NAIC AUSAC Meeting – April 19-20, 2010 Future:Backends Mock single pixel Baseband sampling: –Need to add functionality to cima –Work on pdev headers. –7 or 14 boxes.. –Bandwith per box: Bits1pol Mhz 2pol Mhz
NAIC AUSAC Meeting – April 19-20, 2010 Future:12 meter 12 meter telescope –Integrate with vlbi station observing using dbe –Allow non vlbi usage of telescope with 305m Needs pointing program IF signal needs to be piped into standard backends. Software to support it.
NAIC AUSAC Meeting – April 19-20, 2010 Summary Telescope performance: –Pointing: rmsError: za: 9.0 az:10.6 tot:13.9 asecs Need to fix 1 az term from tilted platform –Gain,Tsys,sefd,Tsys Sefd:800:13.Jy, lbw: 2.5Jy, Cband : 3.3Jy –Get 800 antenna replaced Tsys alfa K (vs za). fix bm2a. –Limitations: Za 3.5->12, daytime fixed position. Future: –12 meter integration. –Backends: Integrate aeronomy, do planetary radar, mock baseband sampling.