Size: 3609
Comment:
|
Size: 8512
Comment:
|
Deletions are marked like this. | Additions are marked like this. |
Line 3: | Line 3: |
Line 8: | 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 IS STILL UNDER CONSTRUCTION''' For the moment, please use the old [http://www.iram.es/IRAMES/telescope/telescopeSummary/telescope_summary.html Telescope System Summary page] [[BR]] 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)]] |
Line 14: | Line 15: |
=== Heterdyne Receivers === | === Heterodyne Receivers === |
Line 16: | Line 17: |
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 | * Eight single pixel receivers A,B,C,D, and the 3x3 dual-polarisation HERA receiver are installed. |
Line 18: | Line 19: |
Table | * Four of the 8 A,B,C,D receivers can be used simultaneously. HERA cannot be combined with other receivers. |
Line 20: | Line 21: |
* 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 2000)] |
Line 23: | Line 23: |
* Noise increasing with frequency | ||'''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.'''|| '''Remarks:''' |
Line 25: | Line 38: |
* 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". | 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. Noise increasing with frequency 1. [http://www.iram.es/IRAMES/mainWiki/HeraWebPage More information on HERA ] [#beginOfPage Back to top] |
Line 29: | Line 47: |
Table | * Two wide field bolometer cameras are installed: |
Line 31: | Line 49: |
local contact for bolometers: Stephane Leon | || 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|| |
Line 33: | Line 53: |
1. rms after 10 minutes (normal bolometric conditions) with skynoise removal. [#beginOfPage Back to top] |
|
Line 36: | Line 58: |
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 . | * 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]. |
Line 38: | Line 60: |
Here you can find the plot with the most recently measured beam efficiencies. | * 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. |
Line 40: | Line 62: |
Table | || 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 42: | Line 76: |
1) The HPBW can be well fit by: HPBW('') = 2460/freq(GHz). | 1. The half power beam width, HPBW, can be well fitted by: HPBW/arcsec = 2460/freq/GHz. |
Line 44: | Line 78: |
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 | 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 46: | Line 80: |
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 | 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. |
Line 48: | Line 82: |
Table | 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] |
Line 50: | Line 85: |
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). | == Backends == |
Line 52: | Line 87: |
== Spectral Line Backends == | === Spectrometers === |
Line 54: | Line 89: |
Table | || || 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. 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. 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. 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. 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 === Bolometer backends === * ABBA1 * ABBA2 [#beginOfPage Back to top] |
Line 57: | Line 115: |
* '''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 * '''Polarimetry''': using VESPA as an IF polarimeter * '''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. |
|
Line 58: | Line 123: |
* 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 * Polarimetry: using VESPA as an IF polarimeter * 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. |
[#beginOfPage Back to top] Moderator: Carsten Kramer, Created by Rainer Mauersberger (1999) |
THIS PAGE IS STILL UNDER CONSTRUCTION For the moment, please use the old [http://www.iram.es/IRAMES/telescope/telescopeSummary/telescope_summary.html Telescope System Summary page] BR
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].
Frontends
Heterodyne Receivers
- Eight single pixel receivers A,B,C,D, and the 3x3 dual-polarisation HERA receiver are installed.
- 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 |
|
|
|
|
|
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. |
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
- Noise increasing with frequency
[http://www.iram.es/IRAMES/mainWiki/HeraWebPage More information on HERA ]
[#beginOfPage Back to top]
Bolometers
- Two wide field bolometer cameras are installed:
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 |
- rms after 10 minutes (normal bolometric conditions) with skynoise removal.
[#beginOfPage Back to top]
Efficiencies and Half-power beam width
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).
[#beginOfPage Back to top]
Backends
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) |
|
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) |
- 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.
- 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
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
- 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
Bolometer backends
- ABBA1
- ABBA2
[#beginOfPage Back to top]
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
Polarimetry: using VESPA as an IF polarimeter
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.
[#beginOfPage Back to top]
Moderator: Carsten Kramer, Created by Rainer Mauersberger (1999)