Monthly Archives

March 2018

Results of radio telescopes: radio-Image of the Sun taken with SPIDER 230C radio telescope. Each pixel corresponds to a numerical value proportional to the intensity (shown in logarithmic scale to better highlight the secondary lobes) of the radio emission coming from that area of the sky.

Experiments: solar radio emission with SPIDER radio telescope

By | Radio astronomy projects | No Comments

Solar radio emission can be studied by using SPIDER radio telescopes. The Sun is in fact one of the most interesting radio source in the sky. In fact the Sun not only emits visible light but also other frequencies in the electromagnetic spectrum. For example, everyone can feel the Sun heat on our skin, expression of infrared radiation. In this article, with step-by-step guide, we see how the SPIDER radio telescopes detect radio waves coming from the Sun and we show how to generate transits, radio images and spectra by using the RadioUniversePRO control software. We perform automatic pointing and tracking on the Sun, detection and removal of eventual artificial signal and capture of different results.

 

Experiments: solar radio emission with SPIDER radio telescope

Experiments: solar radio emission with SPIDER radio telescope

 

The Sun emits radio waves for both thermal mechanisms (due to its high temperature) and for non-thermal (for example synchrotron radiation when the electrons are forced in a spiral motion around magnetic field lines). For wavelengths greater than 1 cm (ie less than about 30 GHz), the solar radio emission is made up of two components: a constant one called “Quiet Sun” due to the heat of our star and a variable one called “Disturbed Sun” that varies over time and depends on the presence of sunspots or flares. SPIDER radio telescopes let you record these emissions. Start RadioUniversePRO software and connect SPIDER’s mount and receiver. In the IF Monitor tab you will see the radio telescope data in real time, as you can see in the picture below.

 

Experiments, solar radio emission with SPIDER radio telescope: RadioUniversePRO control software

Experiments, solar radio emission with SPIDER radio telescope: RadioUniversePRO control software

 

Now select the “Source visibility” tab and double click on the “Sun” radio source. SPIDER radio telescope will automatically point the Sun. In order to verify the perfect alignment on the Sun, you can use the “Offset alignment” feature in the proper tab. Here you can select the proper parameters in order to request the radio telescope “scan” the sky around the Sun position and search for the point of the maximum radio emission, that will correspond to the real position of the Sun in the sky: this way the mount will per perfectly and automatically synced to the sky and will perfectly track and point any radio source. Press the “Start procedure” button to start, SPIDER radio telescope will automatically and precisely detect Sun position, as

 

Experiments, solar radio emission with SPIDER radio telescope: automatic alignment on the Sun with Offset Alignment

Experiments, solar radio emission with SPIDER radio telescope: automatic alignment on the Sun with Offset Alignment

 

Now select BBC Tool tab and check for signal quality. Here you can see if you have interferences caused by artificial signals and easily remove parts of the spectrum, if needed. Please note that interferences caused by artificial signal vary upon your location and the direction pointed by SPIDER radio telescope so you need to check BBC Tools before starting your data recording.

 

Experiments, solar radio emission with SPIDER radio telescope: BBC Tool allow you to remove artificial signal if present

Experiments, solar radio emission with SPIDER radio telescope: BBC Tool allow you to remove artificial signal if present

 

Being sure that we’re perfectly aligned on the Sun and that we’re not recording artificial signals, we can now start recording data and producing results. Let’s start with a Cross-Scan of the Sun. This technique consists in moving the radio telescope creating a cross centered on the object and recording radiometric data for every point: this will allow us to determine the maximum radio emission. In order to perform this operation, we select the “TPI Plot” tab in RadioUniversePRO and use the Cross-Scan feature, by selecting the length of the scan, the separation of every recording point and the integration time of every recording point. SPIDER radio telescope mount progressively moves the antenna position and RadioUniversePRO software creates a graph like this one one you can see in the picture below. Cross-Scan feature can also be used to calculate radio telescope parameters like the half power beam width (HPBW).

 

Experiments, solar radio emission with SPIDER radio telescope: Sun Cross-Scan

Experiments, solar radio emission with SPIDER radio telescope: Sun Cross-Scan

 

Now we produce a radio map, a real image of the Sun recorded in the radio frequencies. We select the “Mapping” tab where we can set all the recording parameters of the radio map. The SPIDER radio telescope will scan the sky area around the Sun, depending on the size of the radio map, the separation and the duration of data capture of each point that compose the map. The map will then be displayed by RadioUniversePRO using one of the different user-selectable color scales. In the image below, the result of the capture of the radio map of the Sun, with an area of 25 degrees of side. The effects of the lateral lobes that form the cross pattern around the central figure of the Sun are also visible.

 

Experiments, solar radio emission with SPIDER radio telescope: Sun radio map

Experiments, solar radio emission with SPIDER radio telescope: Sun radio map

 

Then we move to Sun spectrum recording, using features of the OnOff tab. The OnOff technique consists of recording data from the radio source (“on” position) then moving the radio telescope away from the radio source (“off” position) and recording other data that are used to calibrate the previous ones, also using the appropriate optional noise calibrator SPIDER radio telescopes. The result is visible in the image below, you can see how, unlike discrete emission objects in which, for example, the SPIDER radio telescope is able to capture the hydrogen line, on the Sun there is a continuous broad spectrum emission.

 

Experiments, solar radio emission with SPIDER radio telescope: Sun spectrum

Experiments, solar radio emission with SPIDER radio telescope: Sun spectrum

 

Thanks to SPIDER radio telescope and RadioUniversePRO software, you have a set of data that you can easily compare with data recorded even by professional radio telescopes. Some sources available on the Internet:

Nobeyama Radio Observatory: http://www.nro.nao.ac.jp/en/

Australian Government – Radio and Space Weather Services – Learmonth Observatory: http://www.ips.gov.au/Solar/3/4

Ottawa 10.7cm radio flux: http://www.spaceweather.gc.ca/solarflux/sx-eng.php

Radio astronomy at school with SPIDER radio telescopes: H142-One receiver and control computer with RadioUniversePRO software that controls SPIDER radio telescope visible in the background

Radio astronomy at school with SPIDER radio telescopes

By | Radio astronomy projects | No Comments

Is it possible radio astronomy at school? In general, the activities that many schools develop in astronomy are usually made ​​with optical telescopes because instruments for other electromagnetic spectrum bands are considered too expensive or difficult to use. This often translates into single evening visits with students at the public observatories, so you can not conduct a continuous study. Thanks to our SPIDER radio telescopes is now really possible to make radio astronomy at school because, unlike an optical telescope, they can also be used during the day and then during normal lesson time! The SPIDER radio telescope is installed outside and it’s remotely controlled for example from the classroom or the laboratory.

 

Radio astronomy at school with SPIDER radio telescopes: H142-One receiver and control computer with RadioUniversePRO software that controls SPIDER radio telescope visible in the background

Radio astronomy at school with SPIDER radio telescopes: H142-One receiver and control computer with RadioUniversePRO software that controls SPIDER radio telescope visible in the background

 

Anyone with a satellite dish, an LNB and a SatFinder can point and verify that the Sun emits radio waves. Radio2Space has, however, developed a line of complete radio telescopes with the best performance (and therefore more results) and with greater ease of use. SPIDER radio telescopes, thanks to its great parabolic antenna, precise pointing system,  increased stability and sensitivity of H142-One 1420 MHz radio astronomy receiver for 1420 MHz frequency and advanced RadioUniversePRO control software, is able to pick up radio waves from multiple sources in the Universe. Moreover, thanks to the particular control system, they’re easily remotely controlled and then they’re the perfect instruments to make radio astronomy at school.

 

RadioUniversePRO software for radio astronomy and radio telescope: Offset Alignment

RadioUniversePRO software for radio astronomy and radio telescope: Offset Alignment

 

The activities of radio astronomy at school are many and relate both to astronomy and physics. SPIDER radio telescopes in fact let you not only to record radio waves coming from space but also to study how they are generated in the Universe and how they are collected by the instrument itself. It is thus possible to combine the concepts of physics of electromagnetic waves to the ones of astronomical phenomena that generate them. Although it is more compact (but for this at economic reach of many!) then a professional radio telescope, SPIDER radio telescope can be used to demonstrate to students that different objects in the Universe emit not only visible light but also radio waves. By recording data also in the form of transits or radio images, it is then possible to introduce black body concepts then get to the quantum theory, photons and  various atomic models.

 

Radio astronomy at school with SPIDER radio telescopes: Sun radiomap recorded with SPIDER 300A radio telescope

Radio astronomy at school with SPIDER radio telescopes: Sun radiomap recorded with SPIDER 300A radio telescope

 

SPIDER allow to point and track radio waves coming from many radio sources, also extra galactic and during daytime. You can then also integrate the physics explaining to students why radio waves penetrate clouds while the visible ones are blocked (or greatly diminished). You can then study the phenomena that explain birth of radio waves from many radio sources and study if or why they are polarized. SPIDER radio telescopes come with 1420 MHz receiver developed for radio astronomy: H142-One receiver comes with 1024 channels spectrometer module that allow to record Hydrogen line coming from, example, the Milky Way plane. This way students can study Doppler effect and relative velocities of different parts of the Milky Way.

 

Radio astronomy at school with SPIDER radio telescopes: on-off spectrum of Cassiopea A radio sources with Hydrogen line detection

 

Even objects around us emit radio waves. For example, pointing the radio telescope towards a nearby building, you will notice an increase in the value of radio waves. Comparing this value with the one found by pointing the Sun or the Moon, it will be possible to determine their surface temperature! Thanks to the possibility of calibrating the signal, SPIDER control software lets you to monitor the emission of a radio source for a long time. For example, by focusing to the Sun, you can make one measurement per day for the period of time necessary to its revolution (about 25 days) and then will be able to correlate it with other phenomena such as the number of sunspots visible with an optical telescope (with special filter for protection!).

 

Radio astronomy at school: solar flux at 10cm (from: Spaceweather.com)

 

Finally, note that the radio telescope uses a special radio, the radio astronomy receiver, which can be analyzed and used to make students understand the physical phenomena related to the generation and capture of electromagnetic waves. It will be possible to study how an electric current generates an electromagnetic wave and how a parabolic dish allows you to focus and amplify radio waves. These are only just a few examples on how to use SPIDER radio telescopes to develop radio astronomy at school.