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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 here].

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 2000)]

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.

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 ]

[#beginOfPage Back to top]

Bolometers

Two large field bolometer cameras are installed: MAMBO1 with 37 pixels, and MAMBO2 with 117 pixels. 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 most recent values for the forward and beam efficiencies. We have also compiled the [http://www.iram.es/IRAMES/telescope/telescopeSummary/effi_history.html value of the efficiencies in the past].
Here you can find the [http://www.iram.es/IRAMES/telescope/telescopeSummary/beam_effis.html plot of efficiencies measured in 2000]. A more recent compilation can be found in the Annual Report 2007.

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.
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).

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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)
ABBA1					(6)
ABBA2					(6)

1MHz FB: max 4 parts; series parallel or mixed mode possible; using the filterbanks with 1GHz bandwidth excludes the use of the AC or the 100 MHz FB with the same rx. The FB can be shifted in multiples of 32 MHz from the center frequency of the connected rx.
4MHz FB: max 9 parts; use of the 4 MHz FBs excludes the use of the AC on the same receiver. Frequency switching not available. While the channel spacing is 4MHz, the 3dB width is 5.4 MHz 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]
VESPA: 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
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 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

Observing mode	total power	chopping	position switching	beam switching	frequency switching
Calibrate (Heterodyne)	X
Pointing		X
Focus		X
Tip (Skydip)		X
Track	X				X
ON-OFF			X	X
OTF (Heterodyne)			X		X
OTF (Bolometer)				X
VLBI

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]). Check focus at least at after sunrise and sunset.
Position switching: only relative OFF positions possible (radio projection offsets).
Beam switching with 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 autocorrelators only.
On the fly mapping (Heterodyne): Works with all receiver and backends, typical dump rate 0.5-1 Hz
Polarimetry: using VESPA as an IF polarimeter

[#beginOfPage Back to top]

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

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

-  ⇤ ← Revision 2 as of 2008-08-30 19:53:19 → 
  Size: 1540
  Editor: 24
  Comment:
+   ← Revision 115 as of 2008-09-01 11:53:06 → ⇥
  Size: 10377
  Editor: visitor9
  Comment:
-Deletions are marked like this.
+Additions are marked like this.
 Line 3:
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+Line 7:
-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].    [TableOfContents(3)]]
+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 here].
-Line 13:
+Line 9:
-== Receiver Parameters ==
+[[TableOfContents(4)]]
-Line 15:
+Line 11:
-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. 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
+== Frontends ==
=== Heterodyne Receivers ===
-Line 17:
+Line 14:
-Table
+ * 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 19:
+Line 16:
-. 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
+ * Four of the 8 A,B,C,D receivers can be used simultaneously. HERA cannot be combined with other receivers.
-Line 22:
+Line 18:
-. Noise increasing with frequency
+ * [http://www.iram.es/IRAMES/telescope/telescopeSummary/receiver3.html Plots of the receiver characteristics (taken 2000)]
-Line 24:
+Line 20:
-. 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".
+||'''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.'''||
-Line 26:
+Line 33:
-== Bolometer Parameters ==
-Line 28:
+Line 34:
-Table

local contact for bolometers: Stephane Leon
-Line 33:
+Line 36:
-== Efficiencies and Half-power beam width ==
+'''Remarks:'''
-Line 35:
+Line 38:
-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 .
+. 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 37:
+Line 40:
-Here you can find the plot with the most recently measured beam efficiencies.
+. Noise increasing with frequency
-Line 39:
+Line 42:
+. [http://www.iram.es/IRAMES/mainWiki/HeraWebPage More information on HERA ] 
[#beginOfPage Back to top]

=== Bolometers ===

Two large field bolometer cameras are installed: '''MAMBO1''' with 37 pixels, and '''MAMBO2''' with 117 pixels. 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.]

[#beginOfPage Back to top]

== Telescope efficiencies and beam widths ==

 * Below you find the most recent values for the forward and beam efficiencies. We have also compiled the [http://www.iram.es/IRAMES/telescope/telescopeSummary/effi_history.html value of the efficiencies in the past].

 * Here you can find the [http://www.iram.es/IRAMES/telescope/telescopeSummary/beam_effis.html plot of efficiencies measured in 2000]. A more recent compilation can be found in the Annual Report 2007.

|| 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 ||

 1. The half power beam width, HPBW, can be well fitted by: HPBW/arcsec = 2460/freq/GHz.

 1. 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

 1. 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.

 1. 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).
[#beginOfPage Back to top]

== 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) ||
|| '''ABBA1''' || || || || || (6) ||
|| '''ABBA2''' || || || || || (6) ||

 1. '''1MHz FB''': max 4 parts; series parallel or mixed mode possible; using the filterbanks with 1GHz bandwidth excludes the use of the AC or the 100 MHz FB with the same rx. The FB can be shifted in multiples of 32 MHz from the center frequency of the connected rx.

 1. '''4MHz FB''': max 9 parts; use of the 4 MHz FBs excludes the use of the AC on the same receiver. Frequency switching not available. While the channel spacing is 4MHz, the 3dB width is 5.4 MHz 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]

 1. '''VESPA''': 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. 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 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 ==

|| Observing mode || total power || chopping || position switching || beam switching || frequency switching ||
|| '''Calibrate''' (Heterodyne) || X || || || || ||
|| '''Pointing''' || || X || || || ||
|| '''Focus''' || || X || || || ||
|| '''Tip''' (Skydip) || || X || || || ||
|| '''Track''' || X || || || || X ||
|| '''ON-OFF''' || || || X || X || ||
|| '''OTF''' (Heterodyne) || || || X || || X ||
|| '''OTF''' (Bolometer) || || || || X || ||
|| '''VLBI''' || || || || || ||

 * '''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]). Check focus at least at after sunrise and sunset.
 * '''Position switching''': only relative OFF positions possible (radio projection offsets).
 * '''Beam switching''' with 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 autocorrelators only.
 * '''On the fly mapping (Heterodyne)''': Works with all receiver and backends, typical dump rate 0.5-1 Hz
 * '''Polarimetry''': using VESPA as an IF polarimeter
 


[#beginOfPage Back to top]

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

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