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This page summarizes the present instrumentation installed at the 30m observatory. BR The current system status is described [http://www.iram.es/IRAMES/mainWiki/TelescopeSystemStatus on a second page].

TableOfContents(4)

Frontends

Heterodyne Receivers

Eight single pixel receivers A,B,C,D, and the 3x3 dual-polarisation HERA receiver are installed in the [http://www.iram.es/IRAMES/telescope/telescopeSummary/receiver6.html receiver cabin].
Four of the 8 A,B,C,D receivers can be used simultaneously. HERA cannot be combined with other receivers.
[http://www.iram.es/IRAMES/telescope/telescopeSummary/receiver3.html Plots of the receiver characteristics taken 2007]

Rx	#	Pol	Rx combinations					tuning range	Trx	IF	IF Bw	Gim	Rem.
								[GHz]	[K]	[GHz]	[GHz]	[dB]
A100	1	V	X		X			(72-)80.0-115.5	60-80	1.5	0.5	>20	1.
B100	1	H	X			X		(72-)81.0-115.5	60-85	1.5	0.5	>20	1.
C150	1	V		X		X		130-183	70-125	4	1	15-25
D150	1	H		X	X			130-183	80-125	4	1	08-17
A230	1	V	X		X			197-266	85-150	4	1	12-17
B230	1	H	X			X		197-266	95-160	4	1	12-17
C270	1	V		X		X		241-281	125-250	4	1	10-20	2.
D270	1	H		X	X			241-281	150-250	4	1	9-13	2.
HERA1	9	H					X	215-272	110-380	4	1	~10	2.,3.
HERA2	9	V					X	215-241	120-340	4	1	~10	2.,3.

[http://www.iram.es/IRAMES/groups/receiver/receiver.html More information on the heterodyne receivers.]

Remarks:

Using a special external LO, frequencies down to 77 GHz can be measured with good sideband rejection. For frequencies below 77 GHz, the sideband recection becomes weaker, and the sideband ratio reaches unity at 72 GHz. [http://www.iram.fr/IRAMFR/PV/lowfreqs/report.ps.gz Test report of 2004], [http://www.iram.fr/IRAMFR/PV/lowfreqs/spectra.html Test spectra]
Noise increasing with frequency
[http://www.iram.es/IRAMES/mainWiki/HeraWebPage More information on HERA ]

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Bolometers

Two large field bolometer cameras are installed: MAMBO1 with 37 pixels, and MAMBO2 with 117 pixels ([http://www.mpifr-bonn.mpg.de/div/bolometer/#mamgo MAx-Planck Millimeter BOlometer Array]). Usually MAMBO2 is in use. Both cameras work at 1.2mm wavelength, the HPBW is 11 arcsec, pixel spacing is 20 arcsec, and the sensitivity is 1.5mJy. This is the rms after 10 minutes integration (normal bolometric conditions) with skynoise removal. See [http://www.iram.es/IRAMES/mainWiki/MamboWebPage the MAMBO page for details.]

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Telescope efficiencies and beam widths

Below you find the forward and beam efficiencies measured in March 2005 ([http://www.iram.fr/IRAMFR/ARN/aug05/node6.html IRAM Newsletter 8/05]).

freq	HPBW	Beff	S/TA*	Feff
(GHz)	(arcsec)	(%)	(Jy/K)	(%)
	(1)	(2)	(3)	(4)
72 (extrapolated)	34	79	6.0	95
77 (extrapolated)	32	79	6.0	95
86	29	78	6.0	95
110	22	75	6.3	95
145	17	69	6.7	93
170	14.5	65	7.1	93
210	12	57	7.9	91
235	10.5	52	8.7	91
260	9.5	46	9.5	88
279	9	42	10.4	88

The half power beam width, HPBW, can be well fitted by: HPBW/arcsec = 2460/freq/GHz.
Main beam efficiency Beff. The data can be well fit by a Ruze function Beff = 1.2 epsilon exp[-(4pi R sigma/ lambda)^2] with sigma being the rms value of the telescope optics deformations, R the reduction factor for a steep main reflector, epsilon the aperture efficieny of the perfect telescope and lambda the wavelength in mm. The data can be fit by R*sigma = 0.07 and epsilon = 0.69. The aperture efficiency of the 30-m telescope can be obtained using eta_a=B_eff*0.79
Point source sensitivity S/T_A*. For a Gaussian source and beam size, and a source which is much smaller than the beam, S(Jy)/T_mb(K)=8.18E-7*theta(")**2*nu(GHz)**2 (Rohlfs & Wilson, Tools of Radioastronomy (2. ed., Eq. 8.20). Using the approximation in 1) yields for the 30-m telescope S/T_mb=4.95 Jy/K. S/T_A* is obtained by multiplying 4.95 J/K with F_eff/B_eff.
Forward efficiency Feff: The values for Feff are valid after the 12th of December 2000 when a new reflecting ring was put around the secondary mirror.
Historic values: [http://www.iram.es/IRAMES/telescope/telescopeSummary/beam_effis.html Plot of efficiencies against frequency, measured in 2000], [http://www.iram.es/IRAMES/telescope/telescopeSummary/effi_history.html Compilation of efficiencies obtained in the past till 2001].

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Backends

	Type	Resolution	Bandwidth	Receiver (width mode)	Remark
1 MHz	Filterbank	1 MHz	4x256 MHz, 2x512 MHz, or, 1x1GHz	A100, B100 (narrow), A230, B230, C150, D150, C270, D270 (narrow or wide)	(1)
4 MHz	Filterbanks	4 MHz	9x1GHz	either HERA1 or HERA2 (wide), all other SIS receivers (wide) except 3mm	(2)
WILMA	Autocorrelator	2 MHz	18x930 MHz	HERA (wide)	(3)
VESPA	Autocorrelator	3.3 kHz-1.25 MHz	10-512 MHz	all SIS receives incl. HERA (narrow)	(4)
XPOL	VESPA	40kHz-1.25MHz	120-640MHz	A100 and B100 (narrow)	(5)
ABBA					(6)

In general, several backends can be attached to one receiver. Exceptions are listed below. The [http://www.iram.es/IRAMES/documents/ncs30mPako/Current/PDF/pako.pdf pako manual] describes in detail how to configure the backends.

1MHz Filterbank: max. 4 parts; series, parallel, or mixed mode possible; using the 1MHz filterbank with 1GHz bandwidth excludes the use of VESPA with the same receiver. The filterbank can be shifted in multiples of 32MHz from the center frequency of the connected receiver.
4MHz Filterbank: max. 9 parts; use of the 4MHz filterbank excludes the use of VESPA on the same receiver. Frequency switching not available. While the channel spacing is 4MHz, the 3dB width is 5.4MHz and the noise equivalent width is 6.5 MHz
WILMA: [http://www.iram.fr/IRAMFR/TA/backend/veleta/wilma/index.htm The Wideband Line Multiple Autocorrelator] for HERA
VESPA: [http://www.iram.fr/IRAMFR/TA/backend/veleta/vespa/index.htm The Versatile SPectrometer Array]. Up to 18000 channels. In connection with HERA (9 pixels) the following combinations of resolution (kHz) and bandwidth (MHz) are possible: (20/40), (40,80), (80, 160), (320,320), (1250, 640); [http://www.iram.es/IRAMES/otherDocuments/manuals/vespa_ug.ps VESPA User Guide (2002)], [http://www.iram.es/IRAMFR/ARN/dec02/node6.html Summary in IRAM Newsletter No. 54 (Dec 2002)], local contact: G. Paubert
XPOL: Line and continuum polarimetry is possible at the 30m using a new type of IF polarimeter designated XPOL. The central feature of XPOL is the correlator VESPA where the IF signals from two orthogonally polarized receivers are cross correlated to determine the four Stokes parameters. A manual is in preparation, contact: C. Thum
ABBA1 and ABBA2 (Adc Bolometer Backend) are the bolometer backends, i.e. dedicated PCs connected to the bolometers.

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Control System

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]

Observing modes and source offsets in:

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

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Observing Modes and Switching Modes

Observing mode	swTotal	swBeam	swWobbler	swFrequency
Calibrate (Heterodyne)	X
Pointing	X	X	X
Focus	X	X	X
Tip (Skydip)	X
Track				X
ONOFF	X		X
OTFMAP (Heterodyne)	X			X
OTFMAP (MAMBO Bolometer)			X
VLBI	X

for more details on observing and switching modes, see the section "NCS explained" in the [http://www.iram.es/IRAMES/documents/ncs30mPako/Current/PDF/pako.pdf pako cookbook]
the combination of ONOFF with swTotal is also sometimes called "Position Switching". (swTotal stands for total power observations without switching, while still using the internal synchronization signals.)
Pointing: Using nearby (within 10 degree) pointing sources, <1" accuracy can be obtained; with absolute ("blind") pointing, the accuracy is about 2" rms, the receivers are aligned within 1.7" (see the [http://www.iram.es/IRAMES/mainWiki/TelescopeSystemStatus Telescope Status page] for current values). Checking the pointing and alignment (using e.g. a planet) is the responsibility of the observer.
Focus: residual errors of <1mm may need correction. There are systematic differences of upto 0.6mm in the focus of the different receivers (cf. [http://www.iram.es/IRAMES/mainWiki/TelescopeSystemStatus Telescope Status page]). The focus is subject to change especially during sunrise and sunset.
Position switching: only relative off-source reference positions possible.
Wobbler switching: with wobbling secondary: max. 240" throw at 0.25 Hz, standard phase duration 0.5 Hz.
Frequency switching: max. 45 km/s throw up to about 10 Hz.
On the fly mapping (Heterodyne): Works with all receivers and backends, typical dump rate 0.5 to 10 Hz.
Polarimetry: using VESPA as an IF polarimeter

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Weather station and Taumeter

[http://mrt-lx3.iram.es/tau/meteo-main.php Weather station]
- Wind velocity and direction measured on hill behind the telescope
- Outside temperature and relative humidity measured at base of telescope
- Pressure measured at entrance to control building
[http://mrt-lx3.iram.es/tau/taumeter-main-db.php 225GHz Taumeter] does regular skydips

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Old [http://www.iram.es/IRAMES/telescope/telescopeSummary/telescope_summary.html Telescope System Summary page of September 07]

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

-  ⇤ ← Revision 31 as of 2008-08-30 20:32:51 → 
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+   ← Revision 151 as of 2008-09-24 21:11:52 → ⇥
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-Deletions are marked like this.
+Additions are marked like this.
 Line 6:
- This page summarizes the present instrumentation at the 30m observatory. The current status is described on another  [http://www.iram.es/IRAMES/mainWiki/TelescopeSystemStatus page].
+This page summarizes the '''present instrumentation''' installed at the 30m observatory. [[BR]] The current system '''status''' is described [http://www.iram.es/IRAMES/mainWiki/TelescopeSystemStatus on a second page].
-Line 12:
+Line 13:
-==== A,B,C,D single pixel receivers ====
A maximum of four receivers, from the total of eight, can be used simultaneously. The following table summarizes the allowed combinations and some of the most important receiver characteristics. Plots of the receiver characteristics.
-Line 15:
+Line 14:
-==== HERA 3x3 dual-polarisation 1.2mm array ====
HERA cannot be combined with other receivers; up to now not all frequencies have been pretuned. Hera has 18 pixels separated by 24". Local contact for HERA: Albrecht Sievers
+ * Eight single pixel receivers A,B,C,D, and the 3x3 dual-polarisation HERA receiver are installed in the [http://www.iram.es/IRAMES/telescope/telescopeSummary/receiver6.html receiver cabin].
-Line 18:
+Line 16:
-||'''Rx''' ||'''Pol'''||   ||   ||   ||   || '''tuning range''' || '''Trx'''   || '''IF'''    || '''IF Bw''' || '''Gim'''  || '''Remarks''' ||
||         ||         ||   ||   ||   ||   || '''[GHz]'''        || '''[K]'''   || '''[GHz]''' || '''[GHz]''' || '''[dB]''' || ||
||A100     || V       || X ||   || X ||   || 80.0-115.5         || 60-80       ||  1.5        || 0.5         || >20        || 1. ||
||B100     || H       || X ||   ||   || X || 81.0-115.5         || 60-85       ||  1.5        || 0.5         || >20        || ||
||C150     || V       ||   || X ||   || X || 130-183            || 70-125      ||             ||             ||            || ||
||D150     || H       ||   || X || X ||   || 130-183            || 80-125      ||             ||             ||            || ||
||A230     || V       || X ||   || X ||   || 197-266            || 85-150      ||             ||             ||            || || 
||B230     || H       || X ||   ||   || X || 197-266            || 95-160      ||             ||             ||            || || 
||C270     || V       ||   ||   ||   ||   || 241-281            || 125-250     ||             ||             ||            || || 
||D270     || H       ||   ||   ||   ||   || 241-281            || 150-250     ||             ||             ||            || || 
||HERA     || H       ||   ||   ||   ||   || 215-272            || 110-380     ||             ||             ||            || || 
||HERA     || V       ||   ||   ||   ||   || 215-241            || 120-340     ||             ||             ||            || ||
+ * Four of the 8 A,B,C,D receivers can be used simultaneously. HERA cannot be combined with other receivers.
-Line 31:
+Line 18:
-. Using a special external LO, frequencies down to 77 GHz can be measured with good sideband rejection. For frequencies below 77 GHz, the sideband recection becomes weaker, and the sideband ratio reaches unity at 72 GHz
+ * [http://www.iram.es/IRAMES/telescope/telescopeSummary/receiver3.html Plots of the receiver characteristics taken 2007]

||'''Rx''' ||#||'''Pol'''|||||||||| '''Rx combinations''' ||'''tuning range''' || '''Trx'''   || '''IF'''    || '''IF Bw''' || '''Gim'''  || '''Rem.''' ||
||         ||  ||       ||   ||   ||   ||   || ||'''[GHz]'''        || '''[K]'''   || '''[GHz]''' || '''[GHz]''' || '''[dB]''' || ||
||A100     || 1|| V       || X ||   || X ||   || ||(72-)80.0-115.5         || 60-80       ||  1.5        || 0.5         || >20        || '''1. '''||
||B100     || 1|| H       || X ||   ||   || X || ||(72-)81.0-115.5         || 60-85       ||  1.5        || 0.5         || >20        || '''1.'''||
||C150     || 1|| V       ||   || X ||   || X || ||130-183            || 70-125      ||  4          || 1           || 15-25      || ||
||D150     || 1|| H       ||   || X || X ||   || ||130-183            || 80-125      ||  4          || 1           || 08-17      || ||
||A230     || 1|| V       || X ||   || X ||   || ||197-266            || 85-150      ||  4          || 1           || 12-17      || ||
||B230     || 1|| H       || X ||   ||   || X || ||197-266            || 95-160      ||  4          || 1           || 12-17      || ||
||C270     || 1|| V       ||   || X ||   || X || ||241-281            || 125-250     ||  4          || 1           || 10-20      || '''2.'''||
||D270     || 1|| H       ||   || X || X ||   || ||241-281            || 150-250     ||  4          || 1           ||  9-13      || '''2.'''||
||HERA1     || 9|| H       ||   ||   ||   ||   || X || 215-272            || 110-380     ||  4          || 1           || ~10        || '''2.,3.'''||
||HERA2     || 9|| V       ||   ||   ||   ||   || X || 215-241            || 120-340     ||  4          || 1           || ~10        || '''2.,3.'''||

 * [http://www.iram.es/IRAMES/groups/receiver/receiver.html More information on the heterodyne receivers.]

 
'''Remarks:''' 

 1. Using a special external LO, frequencies down to 77 GHz can be measured with good sideband rejection. For frequencies below 77 GHz, the sideband recection becomes weaker, and the sideband ratio reaches unity at 72 GHz. [http://www.iram.fr/IRAMFR/PV/lowfreqs/report.ps.gz Test report of 2004], [http://www.iram.fr/IRAMFR/PV/lowfreqs/spectra.html Test spectra]
-Line 35:
+Line 42:
-. 2x(3x3) pixel receiver with a 24" separation of the pixels. Equipped with a derotator allowing to follow a source in the sky maintaining the same "footprint".
+. [http://www.iram.es/IRAMES/mainWiki/HeraWebPage More information on HERA ] 
[#beginOfPage Back to top]
-Line 37:
+Line 46:
-Table
-Line 39:
+Line 47:
-local contact for bolometers: Stephane Leon
+Two large field bolometer cameras are installed: '''MAMBO1''' with 37 pixels, and '''MAMBO2''' with 117 pixels ([http://www.mpifr-bonn.mpg.de/div/bolometer/#mamgo MAx-Planck Millimeter BOlometer Array]). Usually MAMBO2 is in use. Both cameras work at 1.2mm wavelength, the HPBW is 11 arcsec, pixel spacing is 20 arcsec, and the sensitivity is 1.5mJy. This is the rms after 10 minutes integration (normal bolometric conditions) with skynoise removal. See [http://www.iram.es/IRAMES/mainWiki/MamboWebPage the MAMBO page for details.]
-Line 41:
+Line 49:
-== Efficiencies and Half-power beam width ==
Below you find the most recent values for the forward and beam efficiencies. We have also compiled the value of the efficiencies in the past .
+[#beginOfPage Back to top]
-Line 44:
+Line 51:
-Here you can find the plot with the most recently measured beam efficiencies.
+== Telescope efficiencies and beam widths ==
-Line 46:
+Line 53:
-Table
+ * Below you find the forward and beam efficiencies measured in March 2005 ([http://www.iram.fr/IRAMFR/ARN/aug05/node6.html IRAM Newsletter 8/05]).
-Line 48:
+Line 55:
-) The HPBW can be well fit by: HPBW('') = 2460/freq(GHz). ''
+|| freq || HPBW || Beff || S/TA* || Feff ||
|| (GHz) || (arcsec) || (%) || (Jy/K) || (%) ||
||            || (1)      || (2) || (3) || (4) ||
||72 (extrapolated) || 34 || 79 || 6.0 || 95 ||
||77 (extrapolated) || 32 || 79 || 6.0 || 95 ||
||86 ||29 || 78 || 6.0 || 95 ||
||110 || 22 || 75 || 6.3 || 95 ||
||145 || 17 || 69 || 6.7 || 93 ||
||170 || 14.5 || 65 || 7.1 || 93 ||
||210 || 12 || 57 || 7.9 || 91 ||
||235 || 10.5 || 52 || 8.7 || 91 ||
||260 || 9.5 || 46 || 9.5 || 88 ||
||279 || 9 || 42 || 10.4 || 88 ||
-Line 50:
+Line 69:
-''2) The data can be well fit by a Ruze function B_eff = 1.2 epsilon exp[-(4pi R sigma/ lambda)^2] with sigma being the rms value of the telescope optics deformations, R the reduction factor for a steep main reflector, epsilon the aperture efficieny of the perfect telescope and lambda the wavelength in mm. The data can be fit by R*sigma = 0.07 and epsilon = 0.69. The aperture efficiency of the 30-m telescope can be obtained using eta_a=B_eff*0.79 ''
+. The '''half power beam width, HPBW''', can be well fitted by: HPBW/arcsec = 2460/freq/GHz.
-Line 52:
+Line 71:
-''3) For a Gaussian source and beam size, and a source which is much smaller than the beam, S(Jy)/T_mb(K)=8.18E-7*theta(")^2*nu(GHz)^2 (Rohlfs & Wilson, Tools of Radioastronomy (2. ed., Eq. 8.20). Using the approximation in 1) yields for the 30-m telescope S/T_mb=4.95 Jy/K. S/T_A* is obtained by multiplying 4.95 J/K with F_eff/B_eff ''
+. '''Main beam efficiency Beff'''. The data can be well fit by a Ruze function Beff = 1.2 epsilon exp[-(4pi R sigma/ lambda)^2] with sigma being the rms value of the telescope optics deformations, R the reduction factor for a steep main reflector, epsilon the aperture efficieny of the perfect telescope and lambda the wavelength in mm. The data can be fit by R*sigma = 0.07 and epsilon = 0.69. The aperture efficiency of the 30-m telescope can be obtained using eta_a=B_eff*0.79
-Line 54:
+Line 73:
-''Table ''
+. '''Point source sensitivity S/T_A*.''' For a Gaussian source and beam size, and a source which is much smaller than the beam, S(Jy)/T_mb(K)=8.18E-7*theta(")**2*nu(GHz)**2 (Rohlfs & Wilson, Tools of Radioastronomy (2. ed., Eq. 8.20). Using the approximation in 1) yields for the 30-m telescope S/T_mb=4.95 Jy/K. S/T_A* is obtained by multiplying 4.95 J/K with F_eff/B_eff.
-Line 56:
+Line 75:
-''4) The values for F_eff are valid after the 12th of December 2000 when a new reflecting ring was put around the secondary mirror. The moon efficiencies are equal to forward efficiencies (Kramer et al. 1997). ''
+. '''Forward efficiency Feff''': The values for Feff are valid after the 12th of December 2000 when a new reflecting ring was put around the secondary mirror. 

 * Historic values: [http://www.iram.es/IRAMES/telescope/telescopeSummary/beam_effis.html Plot of efficiencies against frequency, measured in 2000], [http://www.iram.es/IRAMES/telescope/telescopeSummary/effi_history.html Compilation of efficiencies obtained in the past till 2001]. 

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-Line 59:
+Line 82:
-=== Spectrometers ===
Table
-Line 62:
+Line 83:
-=== Bolometer backends ===
== Spectral Line Observing Modes ==
 * '''Position switching''': only relative OFF positions possible (radio projection offsets).
 * '''Wobbling secondary''': max. 240" throw at 0.25 Hz, standard phase duration 0.5 Hz.
 * '''Frequency switching''': max. 45 km/s throw at max. 0.5 Hz., with 100 kHz filters and autocorrelator only
 * '''On the fly mapping''': Works with all receiver and backends, typical dump rate 0.5-1 Hz
+|| || Type || Resolution || Bandwidth || Receiver (width mode) || Remark ||
|| '''1 MHz''' || Filterbank || 1 MHz || 4x256 MHz, 2x512 MHz, or, 1x1GHz || A100, B100 (narrow), A230, B230, C150, D150, C270, D270 (narrow or wide) || (1) ||
|| '''4 MHz''' || Filterbanks || 4 MHz || 9x1GHz || either HERA1 or HERA2 (wide), all other SIS receivers (wide) except 3mm || (2) ||
|| '''WILMA''' || Autocorrelator || 2 MHz || 18x930 MHz || HERA (wide) || (3) ||
|| '''VESPA''' || Autocorrelator || 3.3 kHz-1.25 MHz || 10-512 MHz || all SIS receives incl. HERA (narrow) || (4) ||
|| '''XPOL''' || VESPA || 40kHz-1.25MHz || 120-640MHz || A100 and B100 (narrow) || (5) ||
|| '''ABBA''' || || || || || (6) ||

In general, several backends can be attached to one receiver. Exceptions are listed below. The [http://www.iram.es/IRAMES/documents/ncs30mPako/Current/PDF/pako.pdf pako manual] describes in detail how to configure the backends.

 1. '''1MHz Filterbank''': max. 4 parts; series, parallel, or mixed mode possible; using the 1MHz filterbank with 1GHz bandwidth excludes the use of VESPA with the same receiver. The filterbank can be shifted in multiples of 32MHz from the center frequency of the connected receiver.

 1. '''4MHz Filterbank''': max. 9 parts; use of the 4MHz filterbank excludes the use of VESPA on the same receiver. Frequency switching not available. While the channel spacing is 4MHz, the 3dB width is 5.4MHz and the noise equivalent width is 6.5 MHz

 1. '''WILMA''': [http://www.iram.fr/IRAMFR/TA/backend/veleta/wilma/index.htm The Wideband Line Multiple Autocorrelator] for HERA

 1. '''VESPA''': [http://www.iram.fr/IRAMFR/TA/backend/veleta/vespa/index.htm The Versatile SPectrometer Array]. Up to 18000 channels. In connection with HERA (9 pixels) the following combinations of resolution (kHz) and bandwidth (MHz) are possible: (20/40), (40,80), (80, 160), (320,320), (1250, 640); [http://www.iram.es/IRAMES/otherDocuments/manuals/vespa_ug.ps VESPA User Guide (2002)], [http://www.iram.es/IRAMFR/ARN/dec02/node6.html Summary in IRAM Newsletter No. 54 (Dec 2002)], local contact: G. Paubert

 1. '''XPOL''': Line and continuum polarimetry is possible at the 30m using a new type of IF polarimeter designated XPOL. The central feature of XPOL is the correlator VESPA where the IF signals from two orthogonally polarized receivers are cross correlated to determine the four Stokes parameters. A manual is in preparation, contact: C. Thum

 1. '''ABBA1 and ABBA2''' (Adc Bolometer Backend) are the bolometer backends, i.e. dedicated PCs connected to the bolometers.


[#beginOfPage Back to top]

== Control System ==

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]
Observing modes and source offsets in:

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

[#beginOfPage Back to top]

== Observing Modes and Switching Modes ==

|| Observing mode                  || swTotal || swBeam || swWobbler || swFrequency ||
|| '''Calibrate''' (Heterodyne)    || X       ||        ||           ||             ||
|| '''Pointing'''                  || X       || X      || X         ||             ||
|| '''Focus'''                     || X       || X      || X         ||             ||
|| '''Tip''' (Skydip)              || X       ||        ||           ||             ||
|| '''Track'''                     ||         ||        ||           || X           ||
|| '''ONOFF'''                     || X       ||        || X         ||             ||
|| '''OTFMAP''' (Heterodyne)       || X       ||        ||           || X           ||
|| '''OTFMAP''' (MAMBO Bolometer)  ||         ||        || X         ||             ||
|| '''VLBI'''                      || X       ||        ||           ||             ||

 * for more details on observing and switching modes, see the section "NCS explained" in the [http://www.iram.es/IRAMES/documents/ncs30mPako/Current/PDF/pako.pdf pako cookbook]


 * the combination of ONOFF with swTotal is also sometimes called "Position Switching". (swTotal stands for total power observations without switching, while still using the internal synchronization signals.)

 * '''Pointing''': Using nearby (within 10 degree) pointing sources, <1" accuracy can be obtained; with absolute ("blind") pointing, the accuracy is about 2" rms, the receivers are aligned within 1.7" (see the  [http://www.iram.es/IRAMES/mainWiki/TelescopeSystemStatus Telescope Status page] for current values). Checking the pointing and alignment (using e.g. a planet) is the responsibility of the observer.
 * '''Focus''': residual errors of <1mm may need correction. There are systematic differences of upto 0.6mm in the focus of the different receivers (cf. [http://www.iram.es/IRAMES/mainWiki/TelescopeSystemStatus Telescope Status page]). The focus is subject to change especially during sunrise and sunset. 
 * '''Position switching''': only relative off-source reference positions possible.
 * '''Wobbler switching''': with wobbling secondary: max. 240" throw at 0.25 Hz, standard phase duration 0.5 Hz.
 * '''Frequency switching''': max. 45 km/s throw up to about 10 Hz.
 * '''On the fly mapping (Heterodyne)''': Works with all receivers and backends, typical dump rate 0.5 to 10 Hz.
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- * '''Pointing''': Using nearby (within 10 degree) pointing sources, <1" accuracy can be obtained; with absolute ("blind") pointing, the accuracy is <4", the receivers are usually aligned within 2". Checking the pointing and alignment (using e.g. a planet) is the responsibility of the observer.
 * '''Focus''': residual errors of <1mm may need correction. There may be systematic differences (<0.4") in the focus of the different receivers. Check focus at least at after sunrise and sunset.
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== Weather station and Taumeter ==

 * [http://mrt-lx3.iram.es/tau/meteo-main.php Weather station]
  *Wind velocity and direction measured on hill behind the telescope
  * Outside temperature and relative humidity measured at base of telescope
  * Pressure measured at entrance to control building

 * [http://mrt-lx3.iram.es/tau/taumeter-main-db.php 225GHz Taumeter] does regular skydips

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Old [http://www.iram.es/IRAMES/telescope/telescopeSummary/telescope_summary.html Telescope System Summary page of September 07] 

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