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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]. | 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]. |
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| * Eight single pixel receivers A,B,C,D, and the 3x3 dual-polarisation HERA receiver are installed. | * 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]. |
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| * [http://www.iram.es/IRAMES/telescope/telescopeSummary/receiver3.html Plots of the receiver characteristics (taken 2000)] | * [http://www.iram.es/IRAMES/telescope/telescopeSummary/receiver3.html Plots of the receiver characteristics taken 2007] |
| Line 20: | Line 20: |
| ||'''Rx''' ||'''Pol'''|| || || || || ||'''tuning range''' || '''Trx''' || '''IF''' || '''IF Bw''' || '''Gim''' || '''Remarks''' || || || || || || || || ||'''[GHz]''' || '''[K]''' || '''[GHz]''' || '''[GHz]''' || '''[dB]''' || || ||A100 || V || X || || X || || ||(72-)80.0-115.5 || 60-80 || 1.5 || 0.5 || >20 || '''1. '''|| ||B100 || H || X || || || X || ||(72-)81.0-115.5 || 60-85 || 1.5 || 0.5 || >20 || '''1.'''|| ||C150 || V || || X || || X || ||130-183 || 70-125 || 4 || 1 || 15-25 || || ||D150 || H || || X || X || || ||130-183 || 80-125 || 4 || 1 || 08-17 || || ||A230 || V || X || || X || || ||197-266 || 85-150 || 4 || 1 || 12-17 || || ||B230 || H || X || || || X || ||197-266 || 95-160 || 4 || 1 || 12-17 || || ||C270 || V || || X || || X || ||241-281 || 125-250 || 4 || 1 || 10-20 || '''2.'''|| ||D270 || H || || X || X || || ||241-281 || 150-250 || 4 || 1 || 9-13 || '''2.'''|| ||HERA1 || H || || || || || X || 215-272 || 110-380 || 4 || 1 || ~10 || '''2.,3.'''|| ||HERA2 || V || || || || || X || 215-241 || 120-340 || 4 || 1 || ~10 || '''2.,3.'''|| |
||'''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.'''|| |
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| 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 | 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] |
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| * Two wide field bolometer cameras are installed: | 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 46: | Line 49: |
| || Bolometer || Beam || Lambda|| Pixels || Spacing || rms (1.) || || MAMBO I || 11"|| 1.2 mm || 37 || 20" || 1.5 mJy|| ||MAMBO II || 11" || 1.2 mm || 117 || 20" || 1.5 mJy|| 1. rms after 10 minutes (normal bolometric conditions) with skynoise removal. |
|
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| == Efficiencies and Half-power beam width == | == Telescope efficiencies and beam widths == |
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| * 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]. | * Below you find the most recent values for the forward and beam efficiencies. |
| Line 57: | Line 55: |
| * 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. | * IRAM Newsletter 8/05: [http://www.iram.fr/IRAMFR/ARN/aug05/node6.html Telescope Efficiencies measured in March 2005]. * 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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| 1. The half power beam width, HPBW, can be well fitted by: HPBW/arcsec = 2460/freq/GHz. | 1. The '''half power beam width, HPBW''', can be well fitted by: HPBW/arcsec = 2460/freq/GHz. |
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| 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. '''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 77: | Line 77: |
| 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. '''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. |
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| 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). | 1. '''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. |
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| === Spectrometers === | || || 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) || |
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| || || 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) || || VESPA || Autocorrelator || 3.3 kHz-1.25 MHz || 10-512 MHz || all SIS receives incl. HERA (narrow) || (3) || || XPOL || VESPA || 40kHz-1.25MHz || 120-640MHz || A100 and B100 (narrow) || (4) || |
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. |
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| 1. 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 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 |
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| 1. max 9 parts; use of the 4 MHz FBs excludes the use of the AC or the 100kHz FB 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] |
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| 1. 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)], local contact: G. Paubert | 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 |
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| 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. '''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 |
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=== Bolometer backends === * ABBA1 * ABBA2 [#beginOfPage Back to top] |
1. '''ABBA1 and ABBA2''' (Adc Bolometer Backend) are the bolometer backends, i.e. dedicated PCs connected to the bolometers. |
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| == Observing Modes == | [#beginOfPage Back to top] |
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| || 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 || || || || || || |
== Observing Modes and Switching Modes == |
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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" (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 may be systematic differences (<0.4") in the focus of the different receivers. 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 100 kHz filters and autocorrelator only * '''On the fly mapping (Heterodyne)''': Works with all receiver and backends, typical dump rate 0.5-1 Hz |
|| 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 ''paKo book'' at: [http://www.iram.es/IRAMES/documents/ncs30mPako/Current/PDF/pako.pdf] * 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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| Old [http://www.iram.es/IRAMES/telescope/telescopeSummary/telescope_summary.html Telescope System Summary page] | Old [http://www.iram.es/IRAMES/telescope/telescopeSummary/telescope_summary.html Telescope System Summary page of September 07] |
| Line 153: | Line 154: |
| Moderator: Carsten Kramer | This is page http://www.iram.es/IRAMES/mainWiki/TelescopeSystemSummary moderated by Carsten Kramer |
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].
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. |
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 ([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.]
[#beginOfPage Back to top]
Telescope efficiencies and beam widths
- Below you find the most recent values for the forward and beam efficiencies.
IRAM Newsletter 8/05: [http://www.iram.fr/IRAMFR/ARN/aug05/node6.html Telescope Efficiencies measured in March 2005].
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].
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.
[#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) |
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]
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
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.
[#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)
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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 paKo book at: [http://www.iram.es/IRAMES/documents/ncs30mPako/Current/PDF/pako.pdf]
- 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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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