Diff for "TelescopeSystemStatus"

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System - General

The 30-m telescope is now operating using the New Control System (NCS) (2005-11-30 HU)

• [http://www.iram.es/IRAMES/ncs30m/ NCS documentation]

  [http://mrt-lx1/mainWiki/FrontPage/ Wiki with up-to-date Notes on NCS (only available locally)]

NCS supports only source coordinates in Equatorial J2000.0 system. (More systems will be made available as soon as possible)

NCS supports observing modes and source offsets in:

• Projection "Radio" (same offsets as in old CS) in Equatorial J2000.0
• "true angle" horizontal
• Nasmyth (receiver offsets)

All 4 Switching Modes are supported by the NCS (total power, beam switching, wobbler switching, frequency switching.)

Observing modes supported by the NCS:

• Calibrate (for heterodyne)
• Pointing
• Focus
• Tip (for bolometer)
• Track (Frequency Switching)
• ON-OFF (Position Switching or Wobbler Switching)
• On-The-Fly Map
• VLBI

Raw data processing software for heterodyne (MIRA) has to be run manually. (Will be automatic as soon as possible!)

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Antenna

OK

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Wobbler

Available under NCS.

Wobbler rotation (actually, secondary rotation) not yet available under NCS.

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Pointing Model

heterodyne: OK, but could be improved (last model update: 2005-11).

bolometer: OK, but could be improved (last model update: 2005-11).

Occasional pointing problems continue to be reported. In order to investigate this, see the next comment!

Operator/AOD: Check regularly that secondary/ spindle control, weather data for refraction correction, and automatic P4/P5 are working correctly -- if necessary ask a member of the NCS team for instructions about this (2005-12).

Pointing on spectral line sources like SiO masers is not available.

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SIS Receivers

A, B, C, D receivers are supported by NCS for observations.

Some problems reported from B100: difficult to lock/tune at some frequencies, higher Trx, ...

Image/Signal gain-ratio calibration is not yet supported by NCS.

Standard table of T_cold calibration temperatures (same as in old CS) is implemented in NCS; note that this covers only a limited standard range of frequencies. Outside this range, T_cold has to be set manually.

Receiver C150 shows low continuum signal at the higher frequencies (>168 GHz). It has to be fully checked. Use D150 instead. (2005-11-16)

HERA is not yet supported by NCS. (to be done for 2006, February).

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Pointing and Flux monitoring with SIS receivers:

Continuum instability ("ripple") can occur with all receivers, making pointing and focusing difficult.

In general some receivers are better then others in this respect as summarized here:

• A100 generally OK for pointing. (2003-11-12) BR B100 OK, is best for pointing. BR C150 often bad for pointing, ripple. (2002-07-16) BR D150 generally good performance for pointing.(2002-07-16) BR A230 often unstable, bad for pointing and flux monitoring. (2003-11-12) BR B230 OK BR C270 very bad for pointing at 265 Ghz. (2002-07-16) BR D270 can be unstable and difficult for pointing. (2002-07-16) BR

  HERA pointing difficulties using beam switch mode - total power mode gave better results but requires excellent weather BR Wobbler switching may avoid ripple, beam switching is most sensitive to ripple

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HERA

HERA is not yet supported by NCS. To be done for 2006-02.

Second polarization installed. One blind pixel. BR SSB tuning tables for standard frequencies. BR Sideband rejections not determined (2004-12-01 AW) BR

Watch the computer control of the derotator closely (2002-12-22). BR Make sure the derotator tracking is stopped after observations, i.e, set to zero degrees in "frame". BR With VESPA, the maximum of 4 spectra per pixel can be used. BR Much higher noise in HERA 2 than HERA 1 when using Vespa. This is being investigated by S. Navarro [RM 30.6.2005]BR When using HERA 1 and 2 configure only 1 Channel for continuum observations in OBS, never-the-less the continuum drifts of all channels are reduced (calibrated) by ODP [AS 11.10.2005]

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Bolometers

Bolometer Observations are supported by the NCS.

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Backends

Support by NCS:

• Continuum Backends for single-pixel heterodyne receivers

• 4 MHz Filterbanks

• 1 MHz Filterbank in parts of 256, 512, 768, or 1024 channels; without frequency shifts.

• 100 kHz Filterbank not yet supported by NCS

• WILMA not yet supported by NCS

• VESPA

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Computer/Software

The 30-m telescope is now operating using the New Control System (NCS) (2005-11-30 HU). Note that the NCS so far supports only a restricted set of features!

Raw data processing software for heterodyne (MIRA) has to be run manually. (Will be automatic as soon as possible!)

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Other Items

OK

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Updates/History

To see the changes between the actual and the last version, please see Show Changes in the Wiki Interface. If you want to see the Revision History of this page, please see Get Info in the Wiki Interface.

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Legend

: OKBR : WarningBR : ErrorBR

The wiki markup of these icons is:

{{{(./) : OK : Warning : Error }}}

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