@@ -106,7 +106,7 @@ In total, the telescope can accomodate up to 20 receivers. A number of additiona
</tbody>
</table>
<p>Active surface</p>
<p>The primary reflector, which is 64 m across, is made of 1008 aluminium panels (with RMS ≤ 65 μm) driven by 1116 electromechanical actuators. This <em>active surface</em>
<p>The primary reflector, which is 64 m across, is made of 1008 aluminium panels (with an RMS ≤ 65 μm each) driven by 1116 electromechanical actuators. This <em>active surface</em>
is designed to compensate for the gravitational deformations of the whole surface at different elevations.</p>
<p>The observer can choose among three configurations:</p>
<ulclass="simple">
...
...
@@ -151,13 +151,13 @@ Each receiver feed allows for two polarizations.</p>
</thead>
<tbodyvalign="top">
<trclass="row-even"><td>P</td>
<td>0.305 – 0.410</td>
<td>0.300 – 0.360</td>
<td>1</td>
<td>linear</td>
<td>primary</td>
<td>56.2’</td>
<td>65?</td>
<td>45?</td>
<td>[50-80]</td>
<td>[45]</td>
<td>125</td>
</tr>
<trclass="row-odd"><td>L</td>
...
...
@@ -166,8 +166,8 @@ Each receiver feed allows for two polarizations.</p>
<td>linear</td>
<td>primary</td>
<td>12.6’</td>
<td>21?</td>
<td>47?</td>
<td>25-35</td>
<td>[47]</td>
<td>36</td>
</tr>
<trclass="row-even"><td>C-high</td>
...
...
@@ -176,7 +176,7 @@ Each receiver feed allows for two polarizations.</p>
<td>circular</td>
<td>beam waveguide</td>
<td>2.8’</td>
<td>26(*)</td>
<td>32-37(*)</td>
<td>48</td>
<td>43(*)</td>
</tr>
...
...
@@ -192,7 +192,8 @@ Each receiver feed allows for two polarizations.</p>
</tr>
</tbody>
</table>
<p>(*) at 6.7 GHz
<p>[ ] is an estimate
(*) at 6.7 GHz
(**) at 22.3 GHz with opacity 0.1 and ground air temperature of 293K.</p>
<p>The FWHM beam size, as a function of the frequency f, can be approximated by the following rule: FWHM(arcmin)=19.7/ f(GHz)</p>
<p>SRT receiver changes are quick, allowing for an efficient frequency agility. The selected receiver is set in its focal position within at most a few minutes.</p>
...
...
@@ -202,14 +203,7 @@ Additionally, a number of high-energy receivers are being planned for the SRT. T
<divclass="section"id="rf-filters">
<h2>RF filters<aclass="headerlink"href="#rf-filters"title="Permalink to this headline">¶</a></h2>
<p>Different RF filters are available for the LP-band receiver. Although it is a coaxial receiver package, the control system sees it as a group of three different receivers, each one with its own code:</p>
<p>For the PPP receiver (P-band), available filters are:</p>
<blockquote>
<div><olclass="arabic simple">
<li>all band, 305–410 MHz (no filter)</li>
<li>310–350 MHz</li>
<li>305–410 MHz (band-pass filter, sharper band edges).</li>
</ol>
</div></blockquote>
<p>For the PPP receiver (P-band), there is one available filter (L2): 300–360 MHz (needed to exclude RFI at higher frequencies).</p>
<p>These are available for the LLP (L-band) configuration:</p>
<blockquote>
<div><olclass="arabic simple">
...
...
@@ -292,14 +286,14 @@ The observer can select the following configurations:</p>
<h2>Pulsar Digital Filter Bank mark 3 (PDFB3)<aclass="headerlink"href="#pulsar-digital-filter-bank-mark-3-pdfb3"title="Permalink to this headline">¶</a></h2>
<p>This is a FX correlator developed by the Australia Telescope National Facility (ATNF) that performs full-Stokes observations. It allows for four inputs, each with a 1024 MHz maximum bandwidth, and 8-bit sampling for a high dynamic range. The DFB3 is suitable for precise pulsar timing and searching, as well as spectral line and continuum observations with a high time resolution. It allows for up to 8192 spectral channels in order to counter the effects of interstellar dispersion when it is operated in pulsar mode, and for power spectrum measurements in spectrometer mode.</p>
<p>This is an FX correlator developed by the Australia Telescope National Facility (ATNF) that performs full-Stokes observations. It allows for four inputs, each with a 1024 MHz maximum bandwidth and 8-bit sampling for a high dynamic range. The DFB3 is suitable for precise pulsar timing and searching. It allows for up to 8192 spectral channels in order to counter the effects of interstellar dispersion.</p>
<p>The main available configurations for pulsar observations are the following:</p>
<tableborder="1"class="docutils">
<colgroup>
<colwidth="17%"/>
<colwidth="23%"/>
<colwidth="28%"/>
<colwidth="32%"/>
<colwidth="16%"/>
<colwidth="24%"/>
<colwidth="27%"/>
<colwidth="33%"/>
</colgroup>
<theadvalign="bottom">
<trclass="row-odd"><thclass="head">Obs type</th>
...
...
@@ -388,7 +382,7 @@ The observer can select the following configurations:</p>
</tbody>
</table>
<p>Further details about the DFB can be found in the ATNF <aclass="reference external"href="http://www.srt.inaf.it/media/uploads/astronomers/dfb.pdf">DFB manual</a>.</p>
<p>At the SRT, DFB observations are piloted using the SEADAS software. For more information:</p>
<p>At the SRT, DFB observations are piloted using the SEADAS software.</p>
<p>Additional, so-called <em>Maccaferri</em> filters are available at L-band at the level of the backends. The recommended filter for pulsar observations at L-band
is the <em>WIDE</em> filter (460 MHz of bandwidth).</p>
</div>
...
...
@@ -402,10 +396,11 @@ is the <em>WIDE</em> filter (460 MHz of bandwidth).</p>
<p>SARDARA is a backend composed of seven fully-reconfigurable ROACH-2 boards that allow it to perform wide-band, full-Stokes observations. The many observing modes covered by SARDARA include: continuum, spectroscopy, spectro-polarimetry, as well as high-time resolution for pulsars and fast transients . Its sampling time can be set from 5ms to 1 s. It is the backend of choice for OTF spectro-polarimetric observations.
Available configurations consist of:</p>
<ulclass="simple">
<li>300 MHz bandwith with 1024 or 16384 channels</li>
<li>420 MHz bandwith with 1024 or 16384 channels</li>
<li>1500 MHz bandwidth with 1024 or 16384 channels</li>
</ul>
<p>The 300 MHz configurations should only be used with the L-Band receiver and the following RF filters: (3) 1350 - 1450 MHz or (5) 1625 - 1715 MHz, in order to avoid aliasing.</p>
<p>The 420 MHz configurations should only be used with the L-Band receiver and the following RF filters: (3) 1350 - 1450 MHz or (5) 1625 - 1715 MHz, in order to avoid aliasing.</p>
<p>SARDARA’s spectral resolution and sensitivity is defined by its full 1500 MHz bandwidth. However only 1200 MHz of the full 1500 MHz bandwidth is usable, since the 1200 MHz filter of the Total Power backend is being used as input to SARDARA.</p>
<p>More detailed information on the SARDARA backend can be found here: <aclass="reference external"href="https://www.worldscientific.com/doi/full/10.1142/S2251171718500046">SARDARA</a>.</p>
</div>
</div>
...
...
@@ -413,71 +408,53 @@ Available configurations consist of:</p>
<h1>Calibration<aclass="headerlink"href="#calibration"title="Permalink to this headline">¶</a></h1>
<divclass="section"id="pointing-calibration">
<h2>Pointing calibration<aclass="headerlink"href="#pointing-calibration"title="Permalink to this headline">¶</a></h2>
<p>Pointing model: this procedure was used to calculate the pointing errors compared to ideal conditions, at night without sunlight. Actual conditions could
require pointing measurements to take into account possible errors due to environmental factors (pointing measurements can be included in the observation schedule).</p>
<ulclass="simple">
<li>C-band</li>
<li>L-band</li>
</ul>
<tableborder="1"class="docutils">
<colgroup>
<colwidth="48%"/>
<colwidth="52%"/>
</colgroup>
<theadvalign="bottom">
<trclass="row-odd"><thclass="head">Parameter</th>
<thclass="head">Value (deg)</th>
</tr>
</thead>
<tbodyvalign="top">
<trclass="row-even"><td>Az-mean</td>
<td>+0.000440</td>
</tr>
<trclass="row-odd"><td>Az-rms</td>
<td>+0.000790</td>
</tr>
<trclass="row-even"><td>El-mean</td>
<td>-0.001660</td>
</tr>
<trclass="row-odd"><td>El-rms</td>
<td>+0.000910</td>
</tr>
</tbody>
</table>
<p>Note: updated as of 2018</p>
<p>Values adopted same as Bolli et al (2015)</p>
<ulclass="simple">
<li>K-band</li>
<li>C-band</li>
</ul>
<tableborder="1"class="docutils">
<colgroup>
<colwidth="48%"/>
<colwidth="52%"/>
<colwidth="19%"/>
<colwidth="41%"/>
<colwidth="41%"/>
</colgroup>
<theadvalign="bottom">
<trclass="row-odd"><thclass="head">Parameter</th>
<thclass="head">Value (deg)</th>
<thclass="head">Value (deg) for C-band</th>
<thclass="head">Value (deg) for K-band</th>
</tr>
</thead>
<tbodyvalign="top">
<trclass="row-even"><td>Az-mean</td>
<td>+0.000440</td>
<td>+0.000850</td>
</tr>
<trclass="row-odd"><td>Az-rms</td>
<td>+0.000790</td>
<td>+0.000870</td>
</tr>
<trclass="row-even"><td>El-mean</td>
<td>-0.001660</td>
<td>-0.001280</td>
</tr>
<trclass="row-odd"><td>El-rms</td>
<td>+0.000910</td>
<td>+0.001200</td>
</tr>
</tbody>
</table>
<p>Note: for K-band, we are keeping the Pointing Model derived in 2012 and used during the ESP (2016).</p>
</div>
<divclass="section"id="focus-curve-calibration">
<h2>Focus curve calibration<aclass="headerlink"href="#focus-curve-calibration"title="Permalink to this headline">¶</a></h2>
<p>The focus curve is applied in real time.</p>
<ulclass="simple">
<li>C-band</li>
</ul>
<p>Figure to attach</p>
<p>We fit the curve with a polynomial of degree 6, such as: y = a x^6+ b x^5 + c x^4 + d x^3 + e x^2 + f x + g</p>
<tableborder="1"class="docutils">
<colgroup>
...
...
@@ -516,72 +493,51 @@ Available configurations consist of:</p>
<ulclass="simple">
<li>K-band</li>
</ul>
<p>We derive the focus curve shown in the Figure below where, as a comparison, we report also the previous focus curve. We report an anomalous behaviour at elevations below 30° that cause severe defocusing.
For this reason, we decide to adopt the old focus curve.</p>
<p>Need table?</p>
</div>
<divclass="section"id="gain-curve-calibration">
<h2>Gain curve calibration<aclass="headerlink"href="#gain-curve-calibration"title="Permalink to this headline">¶</a></h2>
<ulclass="simple">
<li>C-band</li>
<li>L-band</li>
</ul>
<p>Plot of Gain (K/Jy) vs. El (degrees)</p>
<tableborder="1"class="docutils">
<colgroup>
<colwidth="48%"/>
<colwidth="52%"/>
</colgroup>
<theadvalign="bottom">
<trclass="row-odd"><thclass="head">Parameter</th>
<thclass="head">Value</th>
</tr>
</thead>
<tbodyvalign="top">
<trclass="row-even"><td>C0</td>
<td>0.545439</td>
</tr>
<trclass="row-odd"><td>C1</td>
<td>0.00525597</td>
</tr>
<trclass="row-even"><td>C2</td>
<td>-4.55697e-5</td>
</tr>
</tbody>
</table>
<p>Time range valid from May 2018 until… 2017? 2016?</p>
<p>Values adopted same as Bolli et al (2015)</p>
<ulclass="simple">
<li>K-band</li>
<li>C-band</li>
</ul>
<tableborder="1"class="docutils">
<colgroup>
<colwidth="48%"/>
<colwidth="52%"/>
<colwidth="28%"/>
<colwidth="36%"/>
<colwidth="36%"/>
</colgroup>
<theadvalign="bottom">
<trclass="row-odd"><thclass="head">Parameter</th>
<thclass="head">Value</th>
<thclass="head">Value (C-band)</th>
<thclass="head">Value (K-band)</th>
</tr>
</thead>
<tbodyvalign="top">
<trclass="row-even"><td>C0</td>
<td>0.545439</td>
<td>0.505427</td>
</tr>
<trclass="row-odd"><td>C1</td>
<td>0.00525597</td>
<td>0.00864506</td>
</tr>
<trclass="row-even"><td>C2</td>
<td>-4.55697e-5</td>
<td>-6.37184e-5</td>
</tr>
</tbody>
</table>
<p>Due to an issue of misalignment of subscans we could not compute the gain curve from OTF maps. Therefore, as long as the problem is not resolved, we give as a reference the gain curves presented in Prandoni et al. (2017).</p>
<p>C-band Time range valid from 2018.</p>
<p>K-band: from Prandoni et al. (2017).</p>
</div>
<divclass="section"id="beam-shape">
<h2>Beam shape<aclass="headerlink"href="#beam-shape"title="Permalink to this headline">¶</a></h2>
<ulclass="simple">
<li>C-band</li>
</ul>
<p>The beam size and beam deformations in C-band are fully consistent with the measurements reported during the AV and the first commissioning.</p>
<tableborder="1"class="docutils">
<colgroup>
<colwidth="42%"/>
...
...
@@ -624,6 +580,33 @@ For this reason, we decide to adopt the old focus curve.</p>
<ulclass="simple">
<li>K-band</li>
</ul>
<tableborder="1"class="docutils">
<colgroup>
<colwidth="42%"/>
<colwidth="30%"/>
<colwidth="28%"/>
</colgroup>
<theadvalign="bottom">
<trclass="row-odd"><thclass="head">Elevation range (deg)</th>
<thclass="head">Second lobe (%)</th>
<thclass="head">Third lobe (%)</th>
</tr>
</thead>
<tbodyvalign="top">
<trclass="row-even"><td>20-40</td>
<td>11</td>
<td>0.6</td>
</tr>
<trclass="row-odd"><td>40-60</td>
<td>4.9</td>
<td>0.5</td>
</tr>
<trclass="row-even"><td>60-80</td>
<td>3.4</td>
<td>0.5</td>
</tr>
</tbody>
</table>
</div>
<divclass="section"id="list-of-calibrators">
<h2>List of calibrators<aclass="headerlink"href="#list-of-calibrators"title="Permalink to this headline">¶</a></h2>
...
...
@@ -674,7 +657,7 @@ For this reason, we decide to adopt the old focus curve.</p>
<p>Scientific tests and applications for the SRT are described in the following scientific validation paper:
<p>Science done with SRT during its early-science run (2016) with the various hardware and software described below can be found here: <aclass="reference external"href="http://www.srt.inaf.it/astronomers/science_srt/">Science with SRT</a>.</p>
<p>Spectral-polarimetric techniques with SRT: ` Sardinia Radio Telescope wide-band spectral-polarimetric observations of the galaxy cluster 3C 129<<aclass="reference external"href="https://arxiv.org/abs/1607.03636">https://arxiv.org/abs/1607.03636</a>>`_.</p>
<p>Spectral-polarimetric techniques with SRT: <aclass="reference external"href="https://arxiv.org/abs/1607.03636">Sardinia Radio Telescope wide-band spectral-polarimetric observations of the galaxy cluster 3C 129</a>.</p>
@@ -53,13 +53,13 @@ The antenna's main characheristics are:
* - Frequency coverage
- 0.3 -- 115 GHz
* - Primary surface accuracy
- 65 μm rms
- 300 μm rms
* - Pointing accuracy (rms)
- 2 -- 5"
Active surface
The primary reflector, which is 64 m across, is made of 1008 aluminium panels (with RMS ≤ 65 μm) driven by 1116 electromechanical actuators. This *active surface*
The primary reflector, which is 64 m across, is made of 1008 aluminium panels (with an RMS ≤ 65 μm each) driven by 1116 electromechanical actuators. This *active surface*
is designed to compensate for the gravitational deformations of the whole surface at different elevations.
The observer can choose among three configurations:
...
...
@@ -85,12 +85,13 @@ Each receiver feed allows for two polarizations.
(**) at 22.3 GHz with opacity 0.1 and ground air temperature of 293K.
...
...
@@ -108,11 +109,7 @@ RF filters
Different RF filters are available for the LP-band receiver. Although it is a coaxial receiver package, the control system sees it as a group of three different receivers, each one with its own code:
For the PPP receiver (P-band), available filters are:
1. all band, 305--410 MHz (no filter)
2. 310--350 MHz
3. 305--410 MHz (band-pass filter, sharper band edges).
For the PPP receiver (P-band), there is one available filter (L2): 300--360 MHz (needed to exclude RFI at higher frequencies).
These are available for the LLP (L-band) configuration:
...
...
@@ -168,13 +165,13 @@ This digital platform is based on a flexible architecture composed of four ADC b
Pulsar Digital Filter Bank mark 3 (PDFB3)
-----------------------------------------
This is a FX correlator developed by the Australia Telescope National Facility (ATNF) that performs full-Stokes observations. It allows for four inputs, each with a 1024 MHz maximum bandwidth, and 8-bit sampling for a high dynamic range. The DFB3 is suitable for precise pulsar timing and searching, as well as spectral line and continuum observations with a high time resolution. It allows for up to 8192 spectral channels in order to counter the effects of interstellar dispersion when it is operated in pulsar mode, and for power spectrum measurements in spectrometer mode.
This is an FX correlator developed by the Australia Telescope National Facility (ATNF) that performs full-Stokes observations. It allows for four inputs, each with a 1024 MHz maximum bandwidth and 8-bit sampling for a high dynamic range. The DFB3 is suitable for precise pulsar timing and searching. It allows for up to 8192 spectral channels in order to counter the effects of interstellar dispersion.
The main available configurations for pulsar observations are the following:
Further details about the DFB can be found in the ATNF `DFB manual <http://www.srt.inaf.it/media/uploads/astronomers/dfb.pdf>`_.
At the SRT, DFB observations are piloted using the SEADAS software. For more information:
At the SRT, DFB observations are piloted using the SEADAS software.
Additional, so-called *Maccaferri* filters are available at L-band at the level of the backends. The recommended filter for pulsar observations at L-band
is the *WIDE* filter (460 MHz of bandwidth).
...
...
@@ -212,10 +209,12 @@ SARDARA
SARDARA is a backend composed of seven fully-reconfigurable ROACH-2 boards that allow it to perform wide-band, full-Stokes observations. The many observing modes covered by SARDARA include: continuum, spectroscopy, spectro-polarimetry, as well as high-time resolution for pulsars and fast transients . Its sampling time can be set from 5ms to 1 s. It is the backend of choice for OTF spectro-polarimetric observations.
Available configurations consist of:
* 300 MHz bandwith with 1024 or 16384 channels
* 420 MHz bandwith with 1024 or 16384 channels
* 1500 MHz bandwidth with 1024 or 16384 channels
The 300 MHz configurations should only be used with the L-Band receiver and the following RF filters: (3) 1350 - 1450 MHz or (5) 1625 - 1715 MHz, in order to avoid aliasing.
The 420 MHz configurations should only be used with the L-Band receiver and the following RF filters: (3) 1350 - 1450 MHz or (5) 1625 - 1715 MHz, in order to avoid aliasing.
SARDARA's spectral resolution and sensitivity is defined by its full 1500 MHz bandwidth. However only 1200 MHz of the full 1500 MHz bandwidth is usable, since the 1200 MHz filter of the Total Power backend is being used as input to SARDARA.
More detailed information on the SARDARA backend can be found here: `SARDARA <https://www.worldscientific.com/doi/full/10.1142/S2251171718500046>`_.
...
...
@@ -225,38 +224,30 @@ Calibration
Pointing calibration
--------------------
* C-band
Pointing model: this procedure was used to calculate the pointing errors compared to ideal conditions, at night without sunlight. Actual conditions could
require pointing measurements to take into account possible errors due to environmental factors (pointing measurements can be included in the observation schedule).
========== ===========
Parameter Value (deg)
========== ===========
Az-mean +0.000440
Az-rms +0.000790
El-mean -0.001660
El-rms +0.000910
========== ===========
* L-band
Note: updated as of 2018
Values adopted same as Bolli et al (2015)
* K-band
========== ===========
Parameter Value (deg)
========== ===========
Az-mean +0.000850
Az-rms +0.000870
El-mean -0.001280
El-rms +0.001200
========== ===========
* C-band
Note: for K-band, we are keeping the Pointing Model derived in 2012 and used during the ESP (2016).
We fit the curve with a polynomial of degree 6, such as: y = a x^6+ b x^5 + c x^4 + d x^3 + e x^2 + f x + g
...
...
@@ -274,47 +265,32 @@ g 91.5590595452
* K-band
We derive the focus curve shown in the Figure below where, as a comparison, we report also the previous focus curve. We report an anomalous behaviour at elevations below 30° that cause severe defocusing.
For this reason, we decide to adopt the old focus curve.
Need table?
Gain curve calibration
----------------------
* C-band
Plot of Gain (K/Jy) vs. El (degrees)
* L-band
=========== ============
Parameter Value
=========== ============
C0 0.545439
C1 0.00525597
C2 -4.55697e-5
=========== ============
Values adopted same as Bolli et al (2015)
Time range valid from May 2018 until... 2017? 2016?
* C-band
* K-band
=========== ============== ==============
Parameter Value (C-band) Value (K-band)
=========== ============== ==============
C0 0.545439 0.505427
C1 0.00525597 0.00864506
C2 -4.55697e-5 -6.37184e-5
=========== ============== ==============
=========== ============
Parameter Value
=========== ============
C0 0.505427
C1 0.00864506
C2 -6.37184e-5
=========== ============
C-band Time range valid from 2018.
Due to an issue of misalignment of subscans we could not compute the gain curve from OTF maps. Therefore, as long as the problem is not resolved, we give as a reference the gain curves presented in Prandoni et al. (2017).
K-band: from Prandoni et al. (2017).
Beam shape
----------
* C-band
The beam size and beam deformations in C-band are fully consistent with the measurements reported during the AV and the first commissioning.
