Diff for "TelescopeSystemStatus"

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• This page provides information on the status of the 30m telescope for the visiting astronomers. The IRAM staff tries to keep this page up to date as much as possible. It may however happen that some information is outdated. Please contact the Astronomer of Duty or the Operator in case of doubt.

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System - General

The 30-m telescope runs under the New Control System (NCS), see:

• [http://www.iram.es/IRAMES/ncs30m/ NCS documentation] [http://mrt-lx1/mainWiki/ Wiki with up-to-date Notes on NCS]

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

Observations near and towards the Sun are not yet supported.

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:

• total power
• beam switching
• wobbler switching
• frequency switching

Observations with "rotated" wobbler and the bolometer are possible within the pool; contact the pool manager, Stephane Leon, on how to prepare such observations. After finishing with rotated Wobbler, make sure that the operator puts the rotation back to exactly 0 degrees.

Observing modes:

• Calibrate (for heterodyne)
• Pointing
• Focus
• Tip
• Track
  • Frequency Switching
• ON-OFF
  • Position Switching
  • Wobbler Switching
• On-The-Fly Map
  • Heterodyne
    • Total Power (like Position Switching)
    • Frequency Switching
  • Bolometer
    • Wobbler Switching
• VLBI

Automatic calibration and processing of heterodyne data using the MIRA software is in operation for all observing modes. MIRA can also be used manually and offline.

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Antenna

OK

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Wobbler

OK

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Heterodyne Pointing Model and Focus

The Pointing Model is maintained with respect to the 3mm receiver B100. The misalignment and focus error (D-focus) of the other receivers with respect to B100 is the following:

  Rx       misal.(")       date            D_focus(mm)       date
 A100     0.16 ±0.06     27-Feb-07,        +0.09 ±0.03     13-Mar-07
 A230     1.34 ±0.18     27-Feb-07,        +0.43 ±0.02     13-Mar-07
 B100     0.00                              0.00
 B230     1.74 ±0.16     27-Feb-07,        +0.40 ±0.10     17-Apr-07
 C150     1.26 ±0.24      5-Feb-07,        +0.64 ±0.13     17-Apr-07
 C270     0.78 ±0.18      5-Feb-07,        +0.36 ±0.15     17-Apr-07
 D150     1.03 ±0.13     12-Mar-07,        +0.26 ±0.02     12-Mar-07
 D270     1.40 ±0.19     12-Mar-07,        +0.18 ±0.05     12-Mar-07

heterodyne: last model update: 2008-06-25, 29 points, previous rms = 2.58", new rms = 1.97"

Pointing on spectral line sources like SiO masers is not yet supported by the data processing.

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Bolometer Pointing Model

bolometer: last model update: 2007-12-19, 46 points, previous rms = 2.33", new rms = 1.75"

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SIS Receivers A, B, C, D

Image/Signal gain-ratio calibration is supported by NCS, processing in MIRA. It is highly recommended to use this feature!

A standard table of T_cold calibration temperatures for A, B, C, D receivers is implemented in the NCS. This built-in table covers most frequencies. Outside this range, T_cold has to be set manually, ask the RX engineers or operators! Tables and plots:

• http://gra-lx1/mainWiki/ReceiverGroupColdLoadPlotsCurrent (2007-10-11 dj)

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

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HERA

Second polarization installed. BR SSB tuning tables for standard frequencies. BR Sideband rejections not determined (2004-12-01 AW). Use standard value of 0.1! BR

For HERA calibration, measured values of the load temperatures are automatically used!

Watch the computer control of the derotator closely (2002-12-22). Make sure the derotator tracking is stopped after observations, i.e., set to zero degrees in "frame".

The automatic tuning of both HERA1 and 2 can be improved by manually changing the mixer current according to DJ; HERA Pool managers should be aware of this, and operators will receive training (2007-09-19 RM)

HERA 2 is more noisy than HERA 1, limiting HERA2's useful frequency range to below about 242 GHz (2006-09-27 HU according to info from SN)

The control software does not yet support connecting HERA2 to the 4MHz backend (2008-08-29 wb).

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Pointing with SIS receivers A, B, C, D and HERA

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

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

• A100 generally OK for pointing. (2003-11-12) BR B100 OK, is best for pointing. B100 is the standard reference for the heterodyne pointing modelBR 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 can be unstable and difficult for pointing. (2007-04-30) BR D270 can be unstable and difficult for pointing. (2002-07-16) BR With HERA pointing may be difficult using beam switch mode - total power mode may give better results but requires excellent weather BR

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Bolometers

Mambo1 is OFFLINE

Mambo2 was re-installed and commissioned the week 13.11.2007/20.11.2007 (AS)

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Backends

• Continuum Backends
• 4 MHz Filterbanks, note: cannot yet be used with HERA2
• 1 MHz Filterbank in parts of 256, 512, 768, or 1024 channels
• WILMA for observations with HERA

  • Out of operation for 2 o 3 weeks. Hardware upgrade to new broadband receivers (JLS, GP, 05.06.2008)

• VESPA
• ABBA for MAMBO bolometer

• the 100 kHz Filterbank is decommissioned. (RM, HU, 19.9.2007)

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Computer/Software

The NCS supports most essential features, but still has some limitations; see the documentation for details. (see links above)

Online data processing, in a few circumstances, still may have problems with scans extending over midnight. Please check data and report problems to Albrecht Sievers. It may be safer to avoid long scans extending over midnight.

Pako does not run under the default gildas version on mrt-lx3, mrt-lx2. Use gag_aug06 before starting pako (2008-01-15 AS). BR Note: the instructions to start pako explicitly say to run it on mrt-lx1. The trick suggested by AS for mrt-lx2, mrt-lx3 may work, but it is not guaranteed.

Data processing on mrt-lx3 might affect the system performance and slow down the observing system. Observations have priority over any other activity and data processing on mrt-lx3 shall be stopped in this case. Users might try to do dataprocessing on mrt-lx2 in this case. If the observing system is still affected the data processing shall be stopped.(2008-08-29 wb)

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Other Items

Remote observing via VNC is available from Granada, Grenoble, Madrid, and Bonn. See https://mrt-lx1.iram.es/mainWiki/RemoteObserving

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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
{X} : Error

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