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This page provides information on the current status of the 30m telescope. It is intended for visiting astromers at the telescope and for astronomers preparing 30m observations. The IRAM staff tries to keep this page up to date as much as possible, however, some information may still be outdated. Please contact the Astronomer of Duty (AoD) or Operator in case of doubt. For an overview of the entire system and its performance, see the [http://www.iram.es/IRAMES/mainWiki/TelescopeSystemSummary Telescope System Summary]. (CK, 30.8.08)

TableOfContents(3)

System - General

Observations less than 5 degree from the Sun are not yet supported. There is no specific alarm, but integrations don't start and positional deviations remain high.

[#beginOfPage Back to top]

Antenna and wobbling secondary

Observations with high wind speeds are degraded for several reasons. At velocities of more than about 10m/s tracking errors become larger than usual. In addition, the wind load may lead to deformations of the primary dish, depending on direction and orientation of the telescope (Morris et al. 2006). In this case, consider changing to a different source at a different antenna position. If the wind becomes too strong and puts the antenna in danger, the operator may have to decide to stop the observations and put the antenna in the safe stow position. (CK&JP 1.9.08)
The upper elevation limit of the telescope has been set to 83 degrees, when tracking problems are known to set in. In addition, the point source sensitivity is degraded at high elevations and especially for high observing frequencies (see the gain-elevation curves e.g. in the 30m manual). (CK 11.9.08)
Bolometer observations with "rotated" wobbler are now possible. The permitted rotation range is +- 65 deg., in a fixed rotation, without tracking on the sky (the limitation for the tracking comes from the observing program). After finishing with rotated Wobbler, make sure that the operator puts the rotation back to exactly 0 degrees. (JP&CK 1.9.08)

[#beginOfPage Back to top]

Frontends

$/!\$ We recommend sending observing frequencies at least two weeks in advance of an observing run by FAX to the receiver group. This holds in particular for frequencies near the receiver band edges, for HERA2 tunings, and for frequencies below 81 GHz. (to be CHECKEed) (23-8-2008 CK)

SIS Receivers A, B, C, D

Image/Signal gain-ratio calibration using the continuum backends(!) is supported by NCS, processing in MIRA. It is highly recommended to use this feature!
Cold load temperature:
- A standard table of Tcold calibration temperatures for A, B, C, D receivers is implemented in the NCS. This built-in table covers most frequencies. (Use: pako>receiver /temp L)
- $/!\$ Outside this range, Tcold has to be set manually (use pako>receiver /temp "Tcold"), ask the RX engineers or operators! [http://gra-lx1/mainWiki/ReceiverGroupColdLoadPlotsCurrent Tables and plots (internal link)] (2007-10-11 dj)
$/!\$ CHECK Receiver C150 shows low continuum signal at the higher frequencies (>168 GHz). It has to be fully checked. Use D150 instead. (2005-11-16)
In the receiver cabin, Martin-Puplett interferometers MPI are used to seperate frequencies to be send to two different receivers. An overview of the receiver cabin optics is given [http://www.iram.es/IRAMES/telescope/telescopeSummary/receiver6.html here]. The MPIs have high losses at certain frequency ratios, especially at a ratio of 3. Simultaneous observations of e.g. HCN(1-0) and HCN(3-2) or HCO+ are therefore difficult and may lead to increased receiver noise temperatures, depending on how the MPI is optimized.

[#beginOfPage Back to top]

HERA

SSB (Single side band) tuning tables for standard frequencies.
Only few frequencies can be tuned automatically. Observers should send observing frequencies to the IRAM Granada receiver group at least three weeks in advance. (to be CHECKEed)
Sideband rejections not determined (2004-12-01 AW). Use standard value of 0.1!
For HERA calibration, measured values of the load temperatures (Tcold, Thot) 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". Do this also if you continue to observe a source at a large angular distance. In MIRA, after loading a HERA scan, you can visualize the evolution of the derotator angle with time by using command "VIEW /DEROTATOR" (2008-09-12).
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)
Tests have shown that the pixels of HERA-2 (second polarisation) have relatively strong variations of noise over the IF band (LSB Tuning). While the consequences are not too dramatic for wide band operation (WILMA) unfortunately the narrow band mode as used mostly with VESPA picks up the end of the IF band with the highest noise. The problem will be further investigated and eventual improvements indicated asap. To be confirmed at the beginning of the HERA pool (2008-09-30).

[#beginOfPage Back to top]

Bolometers

Details about the bolometers are given on the [http://www.iram.es/IRAMES/telescope/telescopeSummary/telescope_summary.html Telescope Summary page] and on a dedicated [http://www.iram.es/IRAMES/mainWiki/MamboWebPage MAMBO page.]

MAMBO1 is OFFLINE
MAMBO2 is on standby (ck 25.9.08)

[#beginOfPage Back to top]

Backends

$/!\$ VESPA platforming is often caused by total power offsets between different phases, e.g. ON and OFF. VESPA spectra occasionally show spikes at band edges. Check with the AoD to run vespamon.py to check where the problem stems from. The local expert of VESPA is Gabriel Paubert. (30.8.08 ck)
ABBA2 has been reinstalled by Giorgio Siringo (MPIfR) mid September 08.
$/!\$ The 4MHz filterbank occasionally shows platforming. The local contact is Salvador Sanchez. (25.9.08 ck)
13CO and C18O 2-1 can be observed simultaneously with WILMA but not with VESPA. The 2 lines are 839MHz apart.
- With WILMA and 2MHz (2.6km/s@230GHz) resolution, both lines can be observed simultaneously. The WILMA bandwidth is 930MHz.
- VESPA cannot be used to observe both lines simultaneously as the maximum bandwidth of one unit of VESPA is 512MHz. Two high resolution units cannot be moved sufficiently, to cover both lines, as the maximum offset is 250MHz.

[#beginOfPage Back to top]

Computer/Software

The New Control System (NCS) supports source coordinates in Equatorial J2000.0 system. More coordinate systems, i.e. B1950, Galactic Coordinates, etc., will soon be available. You may want to try NASA's [http://heasarc.gsfc.nasa.gov/cgi-bin/Tools/convcoord/convcoord.pl HEASARC tool].
$/!\$ Midnight bug: Online data processing still has occasionally problems with scans extending over midnight. Please check data and report problems to the AoD and Albrecht Sievers. Avoid starting scans directly before UT-midnight. (CK 28.9.08)
It is recommended to run the observations, i.e. to run Pako, on mrt-lx1. On mrt-lx3, mrt-lx2, switch to a different GILDAS version and type gag_aug06, before starting pako (2008-01-15 AS).
$/!\$ Data processing using MIRA or CLASS on mrt-lx3 occasionally slows down the observing system on mrt-lx1 as both system currently access the same disk, /vis, which is at present connected to mrt-lx3. This may mean that the work on mrt-lx3 has to be stopped as observations have priority. Please contact the AoD in case of such problems; for work with CLASS/GREG it helps to copy the 30m file over onto the local disk of mrt-lx2 and to continue working there. For MIRA processing of raw data, this would not help. We are working on a better solution. (2008-08-29 wb, ck). On mrt-lx2, please create a directory /aux/<project> and copy the spectraOdp.30m file to that directory. Use this file only for reading as it is not included in the standard visitor cd/dvd !
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.

[#beginOfPage Back to top]

Pointing

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
 HERA    ~5              04-Aug-08 (for central pixel, staff meeting, JP)

"normal" values for the aditional pointing corrections determined by the observer are close to 0, or +/- a few arc sec.
- a larger value of the pointing correction does not affect the quality of the pointing if
  - it is well determined
  - has no strong variation with azimuth and elevation
  - does not change quickly with time
- please inform the staff (AOD) about good quality pointing corrections that vary by more than 3 arc sec
"normal" values for the optimized focus determined by the observer are close to -2.5mm for the B100 receiver.
- depending on temperature changes (e.g. during sun set or sun rise) and the time of day, this may vary by +/-0.5mm, in extreme cases +/-1mm
- please inform the staff (AOD) about good quality focus results that are not consistent with this
- for good focus results one needs good weather and a strong source that is smaller than the beam, e.g., Mars, only when it is smaller than the beam, or one of the strongest quasars
$/!\$ Pointing on spectral line sources like SiO masers is not yet supported by the data processing.
heterodyne pointing model: last update: 2008-06-25, 29 points, previous rms = 2.58", new rms = 1.97". The coverage and scatter of the pointing session were: attachment:coverage.jpg attachment:scatter.jpg
$/!\$ Observers are adviced to do regularly pointings about every hour or when changing sources.

Bolometer Pointing model

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

[#beginOfPage Back to top]

Pointing with SIS receivers and continuum backends

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)
- B100 OK, is best for pointing. B100 is the standard reference for the heterodyne pointing model
- $/!\$ C150 often bad for pointing, ripple. (2002-07-16)
- D150 generally good performance for pointing.(2002-07-16)
- $/!\$ A230 often unstable, bad for pointing and flux monitoring. (2003-11-12)
- B230 OK
- $/!\$ C270 can be unstable and difficult for pointing. (2007-04-30)
- $/!\$ D270 can be unstable and difficult for pointing. (2002-07-16)
- With HERA pointing may be difficult using beam switch mode - total power mode may give better results but requires excellent weather

[#beginOfPage Back to top]

Updates/History/Legend

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.

: OKBR $/!\$ : WarningBR : ErrorBR

The wiki markup of these icons is:

(./) : OK
/!\ : Warning
{X} : Error

[#beginOfPage Back to top]

This is page http://www.iram.es/IRAMES/mainWiki/TelescopeSystemStatus, moderated by Carsten Kramer

-  ⇤ ← Revision 4 as of 2005-04-22 08:42:59 → 
  Size: 5016
  Editor: gra-lx8
  Comment:
+   ← Revision 275 as of 2008-10-12 08:42:34 → ⇥
  Size: 12825
  Editor: 28
  Comment:
-Deletions are marked like this.
+Additions are marked like this.
 Line 1:
-#acl RainerMauersberger:read,write,admin WalterBrunswig:read,write SantiagoNavarro:read,write DavidJohn:read,write JuanPenalver:read,write SalvadorSanchez:read,write ManuelRuiz:read,write NuriaMarcelino:read,write HansUngerechts:read,write SergioMartin:read,write AlbrecthSievers:read,write AxelWeiss:read,write FredericDamour:read,write GabrielPaubert:read,write montalba:admin,read,write VictorEspigares:admin,read,write All:read
-Line 4:
+Line 3:
 Line 5:
-''(Date 2004-12-01)''
------
+This page provides information on the current status of the 30m telescope. It is intended for visiting astromers at the telescope and for astronomers preparing 30m observations. The IRAM staff tries to keep this page up to date as much as possible, however, some information may still be  outdated. Please contact the Astronomer of Duty (AoD) or Operator in case of doubt. For an overview of the entire system and its performance, see the [http://www.iram.es/IRAMES/mainWiki/TelescopeSystemSummary Telescope System Summary]. (CK, 30.8.08)
 Line 12:
-NORMAL OPERATION
+ * Observations less than 5 degree from the Sun are not yet supported. There is no specific alarm, but integrations don't start and positional deviations remain high.
-Line 16:
+Line 17:
-== Antenna ==
+== Antenna and wobbling secondary ==
-Line 18:
+Line 19:
-OK
+ * Observations with '''high wind speeds''' are degraded for several reasons. At velocities of more than about 10m/s tracking errors become larger than usual. In addition, the wind load may lead to deformations of the primary dish, depending on direction and orientation of the telescope (Morris et al. 2006).  In this case, consider changing to a different source at a different antenna position. If the wind becomes too strong and puts the antenna in danger, the operator may have to decide to stop the observations and put the antenna in the safe stow position. (CK&JP 1.9.08)

 * The upper elevation limit of the telescope has been set to '''83 degrees''', when tracking problems are known to set in. In addition, the point source sensitivity is degraded at high elevations and especially for high observing frequencies (see the gain-elevation curves e.g. in the 30m manual). (CK 11.9.08)

 * Bolometer observations with '''"rotated" wobbler''' are now possible. The permitted rotation range is +- 65 deg., in a fixed rotation, without tracking on the sky (the limitation for the tracking comes from the observing program). After finishing with rotated Wobbler, make sure that the operator puts the rotation back to '''exactly 0 degrees'''. (JP&CK 1.9.08)
-Line 22:
+Line 27:
-== Wobbler ==
+== Frontends ==
-Line 24:
+Line 29:
-Avoid wobbler throw of 120"; with a throw of 120" the specification of a phase time may not work properly.  With a throw of 119 or 121 is should be OK. (2003-07-09)
Results from first pointing after unlocking the wobbler can be  wrong! Usually it's sufficient to ignore the first pointing and repeat the pointing (2003-07-09)
+ * /!\ We recommend sending observing frequencies at least two weeks in advance of an observing run by FAX to the receiver group. This holds in particular for frequencies near the receiver band edges, for HERA2 tunings, and for frequencies below 81 GHz. (to be CHECKEed) (23-8-2008 CK)
-Line 27:
+Line 31:
-Wobbler rotation implemented. Current range: +/- 60deg (2004-12-01 AW)
+=== SIS Receivers A, B, C, D ===

 * Image/Signal gain-ratio calibration using the continuum backends(!) is supported by NCS, processing in MIRA. It is highly recommended to use this feature!

 * Cold load temperature:
  * A standard table of Tcold calibration temperatures for A, B, C, D receivers is implemented in the NCS. This built-in table covers most frequencies. (Use: pako>receiver /temp L) 
  * /!\ Outside this range, Tcold has to be set manually (use pako>receiver /temp "Tcold"), ask the RX engineers or operators! [http://gra-lx1/mainWiki/ReceiverGroupColdLoadPlotsCurrent Tables and plots (internal link)] (2007-10-11 dj)

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

 * In the receiver cabin, Martin-Puplett interferometers MPI are used to seperate frequencies to be send to two different receivers. An overview of the receiver cabin optics is given [http://www.iram.es/IRAMES/telescope/telescopeSummary/receiver6.html here]. The MPIs have high losses at certain frequency ratios, especially at a ratio of 3. Simultaneous observations of e.g. HCN(1-0) and HCN(3-2) or HCO+ are therefore difficult and may lead to increased receiver noise temperatures, depending on how the MPI is optimized.
-Line 31:
+Line 45:
-== Pointing Model ==
+=== HERA ===
-Line 33:
+Line 47:
-heterodyn: OK (last model update: 2004-11-17 ).
bolometer: OK (last model update: 2004-11-02 ).
+ * SSB (Single side band) tuning tables  for  standard frequencies.
-Line 36:
+Line 49:
-Operator/AOD: Check regularly that automatic P4 P5  is working (2002-12-13).
Narrowband continuum pointing (for SiO masers) is out of service! (2003-07-09, 2003-07-30)
+ * Only few frequencies can be tuned automatically. Observers should send observing frequencies to the IRAM Granada receiver group at least three weeks in advance. (to be CHECKEed)
-Line 39:
+Line 51:
-[#beginOfPage Back to top]
 
== SIS Receivers ==
+ * Sideband rejections not determined (2004-12-01 AW).  Use standard value of 0.1!
-Line 43:
+Line 53:
-A, B, C and D receivers are aligned within  3", checked (2003-09-24)
+ * For HERA calibration, measured values of the load temperatures (Tcold, Thot) are automatically used!
-Line 45:
+Line 55:
-Calibration Tcold temperatures have been checked by receiver group.
New scaling factor of 1.0 has been implemented into obs.
Obs Tcold should be ok (2004-01-17)
+ * /!\ 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". Do this also if you continue to observe a source at a large angular distance. In MIRA, after loading a HERA scan, you can visualize the evolution of the derotator angle with time by using command "VIEW /DEROTATOR" (2008-09-12).

 * 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)

 * Tests have shown that the pixels of HERA-2 (second polarisation) have relatively strong variations of noise over the IF band (LSB Tuning). While the consequences are not too dramatic for wide band operation (WILMA) unfortunately the narrow band mode as used mostly with VESPA picks up the end of the IF band with the highest noise. The problem will be further investigated and eventual improvements indicated asap. To be confirmed at the beginning of the HERA pool (2008-09-30).
-Line 51:
+Line 65:
-== Pointing and Flux monitoring with SIS receivers: ==
+=== Bolometers ===
-Line 53:
+Line 67:
-Continuum instability ("ripple") can occur with all receivers, making pointing and focussing difficult.
 In general some receivers are better then others in this respect as summarized here:
+Details about the bolometers are given on the [http://www.iram.es/IRAMES/telescope/telescopeSummary/telescope_summary.html Telescope Summary page] and on a dedicated [http://www.iram.es/IRAMES/mainWiki/MamboWebPage MAMBO page.]
-Line 56:
+Line 69:
-    A100 generally OK for pointing. (2003-11-12)
    B100 OK, will be replaced  (2003-11-12)
    C150 often bad for pointing, ripple. (2002-07-16) 
    D150 generally good performance for pointing.(2002-07-16)
    A230 often unstable, bad for pointing and flux monitoring. (2003-11-12) 
    B230 OK, will be replaced (2003-11-12)
    C270 very bad for pointing at 265 Ghz. (2002-07-16)
    D270 can be unstable and difficult for pointing. (2002-07-16)
    HERA pointing difficulties using beam switch mode - total power mode gave better results (2004-01-17)

[#beginOfPage Back to top]

== HERA ==

Second polarization installed. One blind pixel.
No SSB tuning tables except for few standard frequencies.
Sideband rejections not determined   (2004-12-01 AW)


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".
With VESPA, only two spectra per pixel can be used.

[#beginOfPage Back to top]

== Bolometers ==

Mambo II is installed and ready for operation (AW 2004-12-01)
+ * MAMBO1 is OFFLINE
 * MAMBO2 is on standby (ck 25.9.08)
-Line 89:
+Line 76:
-MHz shift in 100kHz FB header (AW 2004-12-01)
 Software and/or hardware problem in the 1MHz FB  - problem is currently investigated (AW 2004-12-01)
 Spikes in VESPA at intersection of different units (AW 2004-12-01)
+ * /!\ VESPA platforming is often caused by total power offsets between different phases, e.g. ON and OFF. VESPA spectra occasionally show spikes at band edges. Check with the AoD to run vespamon.py to check where the problem stems from. The local expert of VESPA is Gabriel Paubert. (30.8.08 ck)

 * ABBA2 has been reinstalled by Giorgio Siringo (MPIfR) mid September 08. 

 * /!\ The 4MHz filterbank occasionally shows platforming. The local contact is Salvador Sanchez. (25.9.08 ck)

 * 13CO and C18O 2-1 can be observed simultaneously with WILMA but not with VESPA. The 2 lines are 839MHz apart.
  * With WILMA and 2MHz (2.6km/s@230GHz) resolution, both lines can be observed simultaneously. The WILMA bandwidth is 930MHz. 
  * VESPA '''cannot''' be used to observe both lines simultaneously as the maximum bandwidth of one unit of VESPA is 512MHz. Two high resolution units cannot be moved sufficiently, to cover both lines, as the maximum offset is 250MHz.
-Line 97:
+Line 90:
-Mirroring between IRAM Grenoble ( http://www.iram.fr ) and Granada( http://www.iram.es/ ) websites sometimes takes several days to update.   (2003-07-01)
+ * The New Control System (NCS) supports source coordinates in Equatorial J2000.0 system. More coordinate systems, i.e. B1950, Galactic Coordinates, etc., will soon be available. You may want to try NASA's [http://heasarc.gsfc.nasa.gov/cgi-bin/Tools/convcoord/convcoord.pl HEASARC tool].

 * /!\ '''Midnight bug:''' Online data processing still has occasionally problems with scans extending over midnight. Please check data and report problems to the AoD and Albrecht Sievers. Avoid starting scans directly before UT-midnight. (CK 28.9.08)

 * '''It is recommended to run the observations, i.e. to run Pako, on mrt-lx1.''' On mrt-lx3, mrt-lx2, switch to a different GILDAS version and type '''gag_aug06''', before starting pako (2008-01-15 AS). 

 * /!\ Data processing using MIRA or CLASS on mrt-lx3 occasionally slows down the observing system on mrt-lx1 as both system currently access the same disk, /vis, which is at present connected to mrt-lx3. This may mean that the work on mrt-lx3 has to be stopped as '''observations have priority.''' Please contact the AoD in case of such problems; for work with CLASS/GREG it helps to copy the 30m file over onto the local disk of mrt-lx2 and to continue working there. For MIRA processing of raw data, this would not help. We are working on a better solution. (2008-08-29 wb, ck). On mrt-lx2, please create a directory {{{/aux/<project>}}} and copy the spectraOdp.30m file to that directory. Use this file only for reading as it is not included in the standard visitor cd/dvd !

 * 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.
-Line 101:
+Line 102:
-== Other Items ==
+== Pointing ==
-Line 103:
+Line 104:
-OK
+=== 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
 HERA    ~5              04-Aug-08 (for central pixel, staff meeting, JP)               
}}}

 * "normal" values for the aditional pointing corrections determined by the observer are close to 0, or +/- a few arc sec. 
   * a larger value of the pointing correction does not affect the quality of the pointing if
     * it is well determined
     * has no strong variation with azimuth and elevation
     * does not change quickly with time
   * please inform the staff (AOD) about good quality pointing corrections that vary by more than 3 arc sec 

 * "normal" values for the optimized focus determined by the observer are close to '''-2.5mm for the B100 receiver'''. 
   * depending on temperature changes (e.g. during sun set or sun rise) and the time of day, this may vary by +/-0.5mm, in extreme cases +/-1mm
   * please inform the staff (AOD) about good quality focus results that are not consistent with this
   * for good focus results one needs good weather and a strong source that is smaller than the beam, e.g., Mars, only when it is smaller than the beam, or one of the strongest quasars

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

 * heterodyne pointing model: last update: 2008-06-25, 29 points, previous rms = 2.58", new rms = 1.97". The coverage and scatter of the pointing session were: attachment:coverage.jpg attachment:scatter.jpg

 * /!\ Observers are adviced to do regularly pointings about every hour or when changing sources.

=== Bolometer Pointing model ===

 * bolometer pointing model: last update: 2007-12-19, 46 points,  previous rms = 2.33", new rms = 1.75"
[#beginOfPage Back to top]

=== Pointing with SIS receivers and continuum backends ===

 * 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) 

  * B100 OK, is best for pointing. '''B100 is the standard reference for the heterodyne pointing model'''

  * /!\ C150 often bad for pointing, ripple. (2002-07-16) 

  * D150 generally good performance for pointing.(2002-07-16) 

  * /!\ A230 often unstable, bad for pointing and flux monitoring. (2003-11-12) 

  * B230 OK 

  * /!\ C270 can be unstable and difficult for pointing. (2007-04-30) 

  * /!\ D270 can be unstable and difficult for pointing. (2002-07-16) 

  * With HERA pointing may be difficult using beam switch mode - total power mode may give better results but requires excellent weather
-Line 107:
+Line 170:
+== Updates/History/Legend ==
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.
-Line 108:
+Line 173:
-== Updates/History ==
+(./) : OK[[BR]] /!\ : Warning[[BR]] {X} : Error[[BR]]
-Line 110:
+Line 175:
-''(in reverse order by date!)''
+The wiki markup of these icons is:
-Line 112:
+Line 177:
--12-01 AW [[BR]]
    2004-07-24 RM [[BR]]
    2004-03-24, 25 HU [[BR]]
    2004-01-17 AW [[BR]]
    2003-11-12 HU [[BR]]
    2003-09-25 MR [[BR]]
    2003-09-08 HU [[BR]]
    2003-08-20 HU [[BR]]
    2003-08-05 AS [[BR]]
    2003-07-09 RM [[BR]]
    2003-07-01,04/5, 7 HU [[BR]]
    2003-06-08, 09 HU [[BR]]
    2003-04-22, 26 HU [[BR]]
    2003-04-06 AS [[BR]]
    2003-03-31 HU [[BR]]
    2003-03-20 RM [[BR]]
    2003-02-11 AW [[BR]]
    2003-01-10, 2003-01-17, 2003-02-05 RM [[BR]] 
    2003-01-14 TG [[BR]]
    2003-01-03, 06 HU [[BR]]
    2002-12-31 HU [[BR]]
    2002-12-21, 22 HU [[BR]]
    2002-12-19 RM [[BR]]
    2002-12-13, 14, 15, 16 HU [[BR]]
    2002-12-11 RM [[BR]]
    2002-12-05  TG [[BR]]
    2002-11-27 RM [[BR]]
    2002-11-05 AW [[BR]]
    2002-10-18 DJ [[BR]]
    2002-10-15 DJ [[BR]]
    2002-10-09, 12, 14 HU [[BR]]
    2002-10-08 AW [[BR]]
    2002-09-27 TG [[BR]]
    2002-09-26 DJ [[BR]]
    2002-09-23 AW [[BR]] 
    2002-09-11/12, 17 HU [[BR]]
    ... (?) [[BR]]
    2002-08-07,10 HU [[BR]]
    2002-07-22 DJ [[BR]]
    ... (?) [[BR]]
    2002-07-16  HU [[BR]]
    ... (?) [[BR]][[BR]]
+{{{
(./) : OK
/!\ : Warning
{X} : Error
}}}
-Line 157:
+Line 184:
-'''Created by R. Mauersberger, June 18th, 2002'''
+This is page http://www.iram.es/IRAMES/mainWiki/TelescopeSystemStatus, moderated by Carsten Kramer