-- PaulMarganian - 15 Jun 2004

Observing For Dummies

This is meant as a simple guide to people familiar with the GBT and its software, but may not know how to actually observe.

This is NOT Documentation!

Observing For Dummies
- Background
- Pointing
  - Configure
  - GO
  - Observe
- Focus
  - Configure
  - GO
  - Observe
- Galactic HI, Freq SW (no Antenna)
  - Configure
  - GO
  - Observe
- Galactic Plane HI, Freq SW (with Antenna)
- HI Spectral Line, Off/On
  - GO Slew To
  - Configure
  - Balance
  - GO Off On
  - Observe

Background

The sources in the GO Table used for these observations are always up.
You will have to use the CLEO scheduler only for finding the galactic plane.
Remember to always 'source /home/gbt/gbt.bash' in all your command windows.
Pick an appropriate project ID.
You don't have to follow the following observation in the order given, but more details are given for the first couple.
Eventually there should be screen shots of what your obs results should look like for each one of these, so that you know your observation was successfull.
For a combination of additional & out-dated info, see PerformPeakFocusSpectralLine.

Pointing

Configure

At the command line, type 'config_tool'.

Copy the following code into your python session:

Config Case c01_L

GO

Bring up 'GO_LITE' by entering this at the command line.

Set or confirm the following on the main screen:

SW Mode: Total Power
Receiver: 1.15 - 1.73
Observing Proc: Peak
Observing Type: Continuum

Load the GO Table:

press 'GO Tables'
load the table '/users/pmargani/sources.obs', press 'Load'
select lines 3 & 4; press 'Run'
select the continuum source, 3C249_1, line 5, and press 'Run'
confirm that this lines name, RA, & Dec have been loaded in GO.

Set the Procedure parameters for 30 sec scans using GFM:

Offset Mode: Encoder (if using GFM)
RA Rate: 120
DEC Rate: 120
RA Length: 60
DEC Length: 60
Real Time Display: Python (for GFM)
Auto-update Display: Yes

Observe

I.F. Rack:

- Press 'Balance' button
- Confirm that target levels are close to blue sampler box levels

DCR: Get strip charts going of the two active DCR ports to observe total power during scans.

GO: press 'Start'

Observe GFM screen and DCR strip charts. The DCR should show nice gaussians.

Confirm with operator that corrections were sent to the Antenna.

If there are problems with Gfm, try it again with Iards.

Focus

Configure

same script as for Peak observation above. If you want to start fresh, just type g.setup() again in the python session.

GO

Set or confirm the following on the main screen:

SW Mode: Total Power
Receiver: 1.15 - 1.73
Observing Proc: FocusSubreflector
Observing Type: Continuum

Load the GO Table:

press 'GO Tables'
load the table '/users/pmargani/sources.obs', press 'Load'
select lines 3 & 4; press 'Run'
select the continuum source, 3C249_1, line 5, and press 'Run'
confirm that this lines name, RA, & Dec have been loaded in GO.

Set the Procedure parameters for 60 sec scan using GFM:

Offset Mode: Encoder (if using GFM)
Y Start: 250
Y Stop: -250
Focus Rate: 500
Real Time Display: Python (for GFM)
Auto-update Display: Yes

Observe

I.F. Rack:

- Press 'Balance' button
- Confirm that target levels are close to blue sampler box levels

DCR: Get strip charts going of the two active DCR ports to observe total power during scans.

GO: press 'Start'

Observe GFM screen and DCR strip charts. The DCR should show a nice curve.

Confirm with operator that corrections were sent to the Antenna.

If there are problems with Gfm, try it again with Iards.

Galactic HI, Freq SW (no Antenna)

This is the only observation that can be done without moving the Antenna. You might need the following resources: UsingGBTAntennaManagerSimulator, HowToUseAntennaWhenInStow.

Configure

Use one of JimBraatz? 's scripts from his Regression Tests:

from gbtsetup import *
g = gbtsetup()
g.receiver  = 'Rcvr1_2'
g.obstype   = 'Spectroscopy'
g.backend   = 'Spectrometer'
g.nwin      = 1
g.restfreq  = 1420.405
g.deltafreq = 0
g.bandwidth = 50.0
g.swmode    = "sp"
g.swtype    = "fsw"
g.swper     = 1.0
g.swfreq    = 0, 5
g.tint      = 10
g.vlow      = -1000
g.vhigh     = 10000
g.vframe    = "lsrk"
g.vdef      = "Radio"
g.noisecal  =  "lo"
g.pol       = "Linear"
g.nchan  =  "high"
g.spect.levels = 9
g.setup()

GO

Set or confirm the following:

Obs Procedure: Track
Obs Type: Spec. Line Spm
SW Mode: Freq Switch, 01
Source Name: blanksky
Source Velocity: 0
RA: use Antenna's current position
Dec: use Antenna's current position
Az. Rate: 0
Elev. Rate: 0
Duration: 20

Observe

Balance I.F. Rack
Balance Spectrometer
- balance
- prepare
- dont balance
GO: press 'Start'
Observe results in Gfm or Iards: should be a spike at 1420.405

Galactic Plane HI, Freq SW (with Antenna)

Find Galactic Plane

Use CLEO's Scheduler
find convenient coords of red line (this is the Galactic Plane).
write them down.

GO Slew To

Set or confirm the following:

Obs Procedure: SlewTo
Obs Type: Spec. Line Spm
SW Mode: Freq Switch, 01
Source Name: blanksky
Source Velocity: 0
RA: use Galactic Plane RA from above
Dec: use Galactic Plane Dec from above

Slew to the source: press 'Start'.

Configure

Use one of JimBraatz? 's scripts from his Regression Tests:

from gbtsetup import *
g = gbtsetup()
g.receiver  = 'Rcvr1_2'
g.obstype   = 'Spectroscopy'
g.backend   = 'Spectrometer'
g.nwin      = 1
g.restfreq  = 1420.405
g.deltafreq = 0
g.bandwidth = 50.0
g.swmode    = "sp"
g.swtype    = "fsw"
g.swper     = 1.0
g.swfreq    = 0, 5
g.tint      = 10
g.vlow      = -1000
g.vhigh     = 10000
g.vframe    = "lsrk"
g.vdef      = "Radio"
g.noisecal  =  "lo"
g.pol       = "Linear"
g.nchan  =  "high"
g.spect.levels = 9
g.setup()

Balance

Once you are on source, do the following:

Balance I.F. Rack
Balance Spectrometer
- balance
- prepare
- dont balance

GO Track

Set or confirm the following:

Obs Procedure: Track
Obs Type: Spec. Line Spm
SW Mode: Freq Switch, 01
Source Name: blanksky
Source Velocity: 0
RA: use Galactic Plane RA from above
Dec: use Galactic Plane Dec from above
RA Rate: 0
Dec Rate: 0
Duration: 20

Observe

GO: press 'Start'

Observe Gfm or Iards: you should see a spike at 1420.405

HI Spectral Line, Off/On

GO Slew To

Load the HI source from the Go Table:

press 'GO Tables'
load the table '/users/pmargani/sources.obs', press 'Load'
select lines 3 & 4; press 'Run'
select the HI source, U4305o, line 6, and press 'Run'
confirm that this lines name, RA, & Dec have been loaded in GO.

Set or confirm the following:

Obs Procedure: SlewTo

Press 'Start' to get on source.

Configure

Case c07

Balance

Once you are on source, do the following:

Balance I.F. Rack
Balance Spectrometer
- balance
- prepare
- dont balance

GO Off On

Set or confirm the following:

Obs Procedure: OffOn
Obs Type: Spec. Line Spm
SW Mode:
Source Name: U4305o
Source Velocity: 158 Km/s
RA Offset: -8.0
Dec Offset: 0
"On" Integ.: 30

Observe

Get Iards going from a seperate window
GO: press 'Start'
In Iards, is there at spike at 158 Km/s?
Does it resemble the spectrum in Rick Fisher's catalog

Topic ObservingForDummies . { Edit | Attach | Ref-By | Printable | Diffs | r1.1 | More }

Revision r1.1 - 15 Jun 2004 - 14:42 GMT - PaulMarganian Parents: MaintenancePlans > MnCMaintenanceProcess > PerformIntegrationTests > PerformPeakFocusSpectralLine	Content copyright © 1999-2007 by the contributing authors. All material on this collaboration platform is the property of the contributing authors.


NRAO Home > Green Bank \| Wiki Topic: GB > Software > MaintenancePlans > MnCMaintenanceProcess > PerformIntegrationTests > PerformPeakFocusSpectralLine > ObservingForDummies

Changes \| Index \| Contents \| Search \| Statistics \| Go