CABB ObservationsPreparations and Observing

Mark Wieringa

Preparing for the observations

• Plan Frequencies• 20/13 – not yet

• aiming for summed L+S or single 2 GHz band covering both

• 6cm – 5500 MHz

• 3cm – 9000 MHz

• mm – more freedom – two frequencies no more than 6 GHz apart• At 7mm, both frequencies need to be on same side of 41 GHz

• Decide on single/dual freq

• No zoom bands yet, no choice in channel width yet• In progress: 4 zooms per band; 64 MHz channels (for NASA & VLBI)

• RFI• Now unavoidable in lower freq bands (e.g. 5100 MHz)

• Trapped modes show up too

• Set tvchan range in CACOR if calibration affected

• Surveys in progress

CABBScheduler

• New web based scheduler• http://www.narrabri.atnf.csiro.au/observing/sched/cabb

• New schedule format, Caobs no longer accepts old schedules

• New scheduler reads old format schedules (and writes new)

• Features• Recognizes calibrators (from cal database)

• Find calibrator near source (search cal)

• Show calibrator database info

• Integrated velocity calculator (for zoom bands)

• Pick sources from your own catalogue

• Global changes

• Recalculate velocities (for different day/time)

• Missing• Command line, @files, move multiple scans

CABBScheduler – start

CABBScheduler – open file

CABBScheduler – calibrator info

CABBScheduler – frequency panels

CABBScheduler – listing

CABBScheduler – velocity calculator

CABBScheduler – spectral lines

Observing - CAOBS

• CAOBS• Looks the same (mostly)

• Some commands missing (e.g., set atten/coarse, disable auto)• Only mm attenuators remain

• Some commands added (e.g., corr dcal a)• Alternative to typing in cacor window

• Reads only new format schedules

• CACAL • Is no more..

• Calibration is done via CABB commands

• CAMON• Obsolete – use MoniCA gui client instead

• atmon – terminal based MoniCA client• Available for testing, still under development

Observing – VNC based

Caobs and cacor run in separate vncservers (on xbones and caccc0)

A baseline solution at left

Note: delay on cals <0.02ns

Can see atmosphere on CA06

Observing – Vis

• Assistance• Available – needs more ‘tuning’ for CABB

• Obsolete checks removed, no new ones added (yet)

• May be replaced by an ATCA TOAD in few months time

• Vis• Available, working as normal

• May change behind the scenes

• SPD• Available, some new commands (that may change..)

• [no]acs – turn auto correlation display on/off

• [no]ccs – turn cross correlation display on/off

• Off/On F1 – don’t show/show Freq 1 correlations

Observing - SPD

Observing - CACOR

Command:Atts on/off

Sampler tab:Rms ~20 is good

Observing – Setup/Calibration

• New CABB attenuators may need attention at new frequencies• atts on / off in cacor

• look at ‘Samplers’ tab in CACOR to check for rms values near 20

• Calibration now happens in CABB• CACOR Commands:

• Delay calibration: dcal [a]• “dcal” show calculated delays, “dcal a” applies the delay correction

• Phase calibration: pcal [a]• Amplitude calibration: acal flux1 [flux2] [a]

• Supply source fluxdensity for Freq1 [and Freq2]

Observing – Setup/Calibration

• Calibration through CAOBS• CAOBS passes commands on to CACOR

• Prefix with corr, e.g. CAOBS> corr dcal a• May need to do dcal twice if delays are off a long way (>30ns)

• Detailed numbers only visible in CACOR window• Error messages do come back to caobs• When on 1934-638:

• CAOBS> corr acal a

• This will fill in the flux for 1934 before sending cmd to correlator

• Current fit runs from 1GHz to 28 GHz, with CABB 1934 is strong enough at 7mm too (fit will be extended)

• A cacal command may appear in caobs

• Tip• Detach unused antennas to avoid using them in the calibration

Observing with CABB

Questions?