- RECENT HEADLINES
- LT at June 2017 Cosford Air Show
- Spectacular pictures added to LT Picture Gallery
- New Filter for RISE
- Quicker Daily Data Flow and Weekend Data Releases
- Liverpool Telescope group begins collaboration with National Astronomical Research Institute of Thailand
- Photography as art in LJMU online feature
- SPRAT pipeline upgrade
- Liverpool Telescope at the forefront of the search for other Earths
- LT tracks rare microlensed quasar
LJMU video of the Astrophysics Research Institute's involvement at the 2017 RAF Cosford Airshow. © 2017 LJMU
Last month the National Schools' Observatory and the Liverpool Telescope held an exhibition in the "Space Hangar" at the 2017 Royal Air Force Cosford Air Show. A news article about this event is now on the Liverpool John Moores University news site, which features a great video shot by LJMU's press office, which is also shown above. Click here to go to the article "Tales from the Liverpool Telescope".
The exhibit featured scale models of the LT, plus its proposed 4 metre diameter successor Liverpool Telescope 2 (LT2). The size of the venue also allowed full-size mockups of LT and LT2 primary mirrors to be constructed, to give the public a very real impression of the size of professional telescope optics.
A small sample of the 70+ LT images submitted to the Gallery. © 2017 Göran Nilsson and Wim van Berlo.
The pictures were made by taking archived greyscale IO:O data that had been observed through effectively red, green and blue filters, and combining them in various ways to produce colour images. Most of the original data had been requested over the years by UK schools via the National Schools' Observatory
This skilful post-processing was performed by Swedish amateur astrophotographers Göran Nilsson and Wim van Berlo.
Göran is a professor in animal physiology at the University of Oslo, and Wim is a physics and mathematics teacher in Stockholm. Both have been interested in astronomy and astrophotography for some time; Göran even built his own observatory in the Swedish countryside in 2014.
Living so far north has its drawbacks however when it comes to astrophotography in the summer. "During a four month period, from May through August, the sun hardly sets below the horizon, and it doesn’t get dark," says Wim. Göran, situated even further north, has the same experience: "The long light summer nights make astrophotography impossible for several months," he says.
To have something astronomy-related to do during this time, the two decided to use their growing astrophotography skills to process exposures that were freely available from the Liverpool Telescope's Data Archive. Together they sifted through all available data for each of the objects they chose, stacking and combining the frames. Göran used the program Nebulosity for stacking, following up with Adobe Photoshop for final contrast enhancements that reveal hitherto unseen fine detail. Wim performed the same tasks entirely with the single package PixInsight.
The result is over seventy stunning full-colour pictures of famous and some not-so-famous astronomical objects. We are certainly delighted with the pictures, and thank Göran and Wim for allowing us to host their work on our website.
The RISE fast-readout camera is having its "V+R" filter replaced with a 720 nm long-pass filter on 26th July 2017. This is being done to enhance the capabilities of the camera with regard to measurement of exoplanet transits around late-type, red dwarf stars.
More details of the filter switch can be found in the filter section of the RISE instrument page here.
© Tomas Castelazo, www.tomascastelazo.com / Wikimedia Commons /
CC BY-SA 4.0
Regular telescope users may have noticed their daily data releases are coming a little earlier than in the past. Our data handling procedures have been updated to speed things up. Though the LT is designed to all be fully automated, to date we have deliberately inserted one manual break-point in the data flow such that after all the data are pipeline processed they are not released to you until one of us has had a look through all the night’s data as a quality assurance check. Experience has shown however that for the few occasions when this procedure has identified an instrument failure there are very many cases where we were unnecessarily delaying distribution of time sensitive data. Our new policy therefore is to release all data into the science archive as soon as possible each morning.
All science data are now typically available in both the Recent Data and searchable science archives between 09:30 and 10:30 UTC on the morning after they were observed. You will continue, as now, to get an email as soon as the data are available. Having removed the human interaction from the process, the data releases are now also being made seven days a week.
Those who use RISE at a high frame rate over several hours to generate large data sets may find their data arrive a little later than the estimate above. This is simply limited by the bandwidth from La Palma back to Liverpool. The data will be released as soon as the entire night’s observations have been transferred.
We are only here talking about the final science-ready archived data reductions. Quicklook continues to operate as before for those who need real-time, intra-night access to the data as soon as they are observed.
Besides better serving the time domain astrophysics community, there is one very obvious side effect to this change. We in the LT operations team will no longer see every frame taken and there is greater risk of telescope or instrument faults going un-noticed. The LT has a very wide array of in-house developed, automated telemetry processes that continually monitor system performance for us from hydraulic oil temperatures, through on-sky pointing residuals, instrument amplifier read noise and final archive image quality. These autonomous systems are effective at alerting us to many possible error states, but they will not detect everything. We are therefore now becoming much more dependent on you, the telescope users, to help run the observatory efficiently. We encourage all observers to routinely look at their new data and contact us about any problems you see. This is not only about technical faults. We have in the past been able to alert observers to mistakes in their phase 2 configurations that were revealed by poor data quality. Now the responsibility for ensuring that the data match expectations rests more heavily on all observers for their own data. We are always happy to advise on how best to exploit the telescope facilities if you get in touch to discuss your science objectives.
Earlier this month, a deputation of Liverpool Telescope (LT) staff visited the National Astromical Research Institute of Thailand (NARIT) in the city of Chiang Mai. The purpose of the visit was to begin a programme of collaborative software development, funded by STFC through the Newton Fund. The purpose of the Newton Fund is to use science and innovation partnerships to promote economic development and social welfare in partner countries.
The collaborative programme between the LT and NARIT is based around two projects: the development of a new, modern data archiving framework and a new telescope control system. At the end of the three-year programme, these products will replace the existing systems on LT and NARIT facilities, and will also be a component in the new software which will be required for the Large Robotic Telescope (Liverpool Telescope 2).
Robert Smith's "Iridis" image of the Cat's Eye Nebula (featured in full here) has inspired an article on the Liverpool John Moores University (LJMU) main website about the more general concept of science as art, and art as science.
The image won the Robotic Scope Special Prize at the Insight Astronomy Photographer of the Year 2016. It was taken with the Liverpool Telescope's SPRAT spectrograph in slitless mode, so the light from the nebula was split into its constituent colours without first passing through a slit. As the nebula shines only in discrete colours, just a few individual images of the nebula can be seen, instead of a continuous spread from blue through to red.
Smith says: “We often hear about the idea of representing scientific data in an appealing way as an expression of art, but why not look at it the other way around; ‘art as science’? Astrophotography is not just a matter of making science look pretty, it shows us that beauty actually is science. The winners of this competition were obviously selected because they were beautiful, striking or interesting, but each and every one is also an expression of astrophysical processes and could be the basis of a science seminar in their own right. It is physics that creates that beauty. Looking at the swirling gas in a nebula or the aurorae, you are literally seeing maths and physics.”
All instruments on the Liverpool Telescope (LT) have automated data "pipelines" that process the raw data from the telescope into a finished form, i.e. science-ready data products, for the user to download the next working day. Not long ago the LT's SPectrograph for the Rapid Acquisition of Transients (SPRAT) got a major upgrade to its level 2 pipeline.
All data pass through a "Level 1" (L1) pipeline that removes low-level instrumental signatures such as bias, dark and flat-field effects. The SPRAT "Level 2" (L2) pipeline carried on from there to perform source extraction, sky subtraction and wavelength calibration, outputting 1D and 2D spectra as part of the process. All data products from the Level 2 SPRAT pipeline are stored as extra extensions in the SPRAT FITS files.
The upgrade to the L2 pipeline is that it now also performs flux calibration, stored as an extra FITS extension. This is a basic calibration that uses a template instrument response file, and generates its absolute calibration from the acquisition image. The precision is fine for the transient classification work that SPRAT is used for, and so will be very useful for the users performing that type of science.
Full details of the new SPRAT L2 pipeline can be found on the SPRAT webpage.
Liverpool Telescope helps to track down seven new planets
The Liverpool Telescope has helped to find seven Earth-sized worlds.
The discovery of a system of seven Earth-sized planets just 40 light-years away was made possible by a team of astronomers from across the world.
The research, published in Nature this week, was led by the STAR Institute at the University of Liège, and used the orbiting NASA Spitzer Space Telescope in addition to ground-based facilities including the Liverpool Telescope (LT), owned and operated by Liverpool John Moores University's Astrophysics Research Institute (ARI).
The LT helped to detect the planets as they passed in front of their parent star, the ultracool dwarf star known as TRAPPIST-1. At least three of the planets could harbour oceans of water on their surfaces, increasing the possibility that the star system may play host to life. This system has both the largest number of Earth-sized planets yet found, making it a key object for future study.
Dr Chris Copperwheat, a co-author on the paper, and a member of the ARI, commented on the role of the LT:
“LJMU is at the forefront of the search for other-Earths and the search for other life in the Universe. The Astrophysics Research Institute was delighted to be part of this ground-breaking research using the Liverpool Telescope. The discovery of multiple rocky planets with surface temperatures which allow for liquid water make this amazing system an exciting future target in the search for life."
"As a robotic telescope and the largest in the world, the Liverpool Telescope is very sensitive to the small, less than 1 per cent dips in brightness through which the planets are discovered. It's all automated, it’s flexible and fast, and so is ideal for this sort of time critical work. Supporting the orbiting NASA Spitzer Space Telescope observing schedule, often at very short notice, is a simple task for astronomers who can use our telescope from anywhere in the world.”
The ARI is currently in the process of designing the New Robotic Telescope, a facility which will take the Liverpool Telescope’s crown as the world’s largest robotic telescope dedicated to science, and which will be a powerful tool in the search for other Earths, liquid water and life over the coming decades.
The Liverpool Telescope is one of the largest and most advanced fully robotic telescopes in the world, especially dedicated to the study of variable and transient astronomical phenomena. The timelapse video above shows this giant robot observing the universe at the Instituto de Astrofísica de Canarias (IAC) Roque de los Muchachos Observatory on the summit of La Palma (Canary Islands, Spain), one of the best places on Earth for astronomical observations.
The Liverpool Telescope is mainly used for professional astronomical research, although part of its observational time is devoted to educational projects. In Spain, these are run by the Educational Project with Robotic Telescopes (PETeR) of the IAC, while in the UK, they're run by the National Schools’ Observatory (NSO) at LJMU. The timelapse above is a production of the IAC Communication and Scientific Culture Unit and Daniel López (www.elcielodecanarias.com), with the collaboration of the LJMU Astrophysics Research Institute.
In a paper entitled "Gravitational lens system SDSS J1339+1310: microlensing factory and time delay" currently in preprint at arXiv , authors Luis Julian Goicoechea Santamaria and Vyacheslav Shalyapin reveal how the Liverpool Telescope (LT) has been used to characterise a gravitational lens created by a foreground galaxy in direct line with a much more distant quasar.
Light from the quasar that is heading in the general direction of Earth is passing either side of the foreground galaxy, and is being bent by the galaxy's gravity to meet at a focus at the Solar System.
From Earth we therefore see two images of the quasar, but because each light path takes a slightly different route around the galaxy, one longer than the other, the images are out of sync. Therefore any disturbance or variation in brightness from the quasar will be seen first in one image, and then repeated after some delay in the other image.
The LT data has not only revealed the time delay between both images, and also that the lensing galaxy is causing microlensing with its constituent stars along the light paths from the quasar.
Since 2005, the Gravitational LENses and DArk MAtter (GLENDAMA) team has been conducting optical monitoring of about 10 gravitationally lensed quasars with the LT. For each target, the main goals are to measure time delays between the multiple quasar images, as well as analyse the intrinsic variability of the lensed source and the possible flux variations caused by microlenses (stars) in the lensing galaxy.
After an 8-year monitoring campaign of the double quasar SDSS J1339+1310 in SDSS-R band, the LT light curves of its two images, A and B, are characterised by typical photometric accuracies of 1-2% and an average sampling rate of once every 6 days (excluding gaps).
These light curves show parallel V-shaped variations, which allowed the GLENDAMA team to determine a time delay of 47 days with 10% precision.
In addition, the accurate follow-up observations of both images reveal the presence of significant microlensing-induced flux variations on different timescales, including rapid microlensing events lasting 50-100 days.
While the strong microlensing activity precludes a more accurate estimation of the delay between A and B, the rapid events are very rare phenomena, and thus unique tools for astrophysical studies.
Optical spectra taken with the Gran Telescopio Canarias (GTC) confirm that the system SDSS J1339+1310 is an unusual “microlensing factory”, since appreciable microlensing-induced spectral distortions are also detected.
The paper was accepted in September 2016 for publication in the journal Astronomy & Astrophysics, and is expected to be published soon.