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Introduction
This month’s Newsletter is slightly briefer than most, because most of those who might have contributed to it have been occupied with preparation of the proposal for the LSST:UK contribution to Rubin Observatory operations. The main portion of the proposal was submitted on 25 September, with extensions requested to allow later submission of text describing three proposed contributions - relating to participation in Commissioning, annual Data Release Processing and operation of a Data Access Centre - where discussions with Observatory staff are continuing. The proposal will be assessed by Observatory staff and by the Contribution Evaluation Committee, with the assessment process expected to conclude next April with the US agencies making decisions on “approval to Rubin to establish data rights agreements and grant interim data access”, with final data rights agreements to be signed by the middle of next year. The content of the proposal was approved prior to submission by the LSST:UK Consortium Board and carries an endorsement from Colin Vincent, Associate Director Astronomy at STFC.
Those with ideas for future newsletter items should contact the LSST:UK Project Managers (George Beckett and Terry Sloan: lusc_pm@mlist.is.ed.ac.uk), while everyone is encouraged to subscribe to the Rubin Observatory Digest for more general news from the US observatory team.
2020 Rubin Observatory Project and Community Workshop
The 2020 Project and Community Workshop (PCW) took place online on August 10-14, with approximately four hours of presentations per day, divided into three main sessions. The table below presents the workshop schedule, with links to relevant page on the PCW website, from which presentation materials - including YouTube recordings of the sessions - can be accessed.
Monday
Tuesday
Wednesday
Thursday
Friday
Plenary 1: Construction QA
Plenary 2: Operations QA
Plenary 3: Science Collaborations Report
Plenary 4: Science Keynote: "From disruption, opportunity: the current and future impact of AI on astronomy" (Dr. Brian Nord)
Rubin Research Bytes
(contributed flash talks)
In-kind proposal workshop
(repeat)
There is a lot of interesting material there, but, obviously, the plenary sessions are a good place to start.
The Rubin staff and Science Collaboration leaders put a lot of thought into how to make a large conference work online. Through the provision of pre-recorded videos and other preparatory materials to study before the sessions, and with dedicated staff carefully monitoring session-specific Slack channels as well as the Zoom chat window, it proved possible to circumvent some of the limitations of the medium, and to get some level of interaction amongst the globally-distributed online participants, although, of course, there is no real online substitute for the chat in the coffee break or in the bar after dinner.
The impact of satellite constellations on the Legacy Survey of Space and Time
Few astronomers can have missed images like that shown on the right of SpaceX Starlink satellites crossing the field of view of the Blanco telescope at CTIO soon after launch last November. Quantitative assessment of the impact of LEO satellite constellations has begun in earnest, with a particular focus on the Rubin Observatory, since the high etendue that make the Simonyi Survey Telescope so powerful for survey astronomy also makes it particularly vulnerable to the effects of LEO constellations, since, crudely, it covers too much of the sky too quickly to make it possible just to dodge the satellites.
First results from these studies were presented at the end of June at a workshop - SATCON1 - organised by the AAS and NSF’s NOIRLab. A report from that workshop has now been published, along with technical appendices, while the workshop website also has copies of the presentations made by members of four working groups, covering observations, simulations, mitigations and metrics. More sophisticated simulations will be needed for detailed assessment of the impact on particular LSST science cases, but it is clear that constellations of LEO satellites will affect astronomy significantly - this initiative focuses on optical/NIR, but there are analogous issues in the radio - requiring coordinated action between the astronomical community and the satellite operators. There is a hierarchy of effects, some of which can be mitigated relatively easily, some of which are harder, and some, especially those relating to twilight observations, seem set to remain, whatever is done. SATCON1 is a good start, but this is, clearly, a topic that will require significant attention from the community in the coming years.
Starlink satellites imaged on 18 Nov 2019 from the Victor M. Blanco 4m Telescope at CTIO.
Image Credit: CTIO/NOIRLab/NSF/AURA/DELVE
Lasair
Lasair-ZTF is now a mature working service, and development of Lasair-LSST is well underway! In this item we will take a quick look at what you can do now, and where we are headed. We have already benefited from considerable user input, but more is always welcome.The Rubin Observatory is expected to produce (on average) 10 million alerts every night. Getting these to users is a real challenge; the project approach is to feed the stream to third party services known as community brokers. A review process is underway to select a small number of these; the LSST:UK offering is the Lasair broker, being developed by a team in Belfast and Edinburgh. Lasair means "flame" or "flash" in both Irish and Scots Gaelic, which seems appropriate for this Celtic Collaboration. We showcased our efforts so far at a dedicated brokers session at the recent Rubin Observatory "Project and Community Workshop", recently held on line (see the item by Bob Mann in this newsletter).
To prototype Lasair, we built a system to process nightly alerts from the Zwicky Transient Facility (ZTF). However, this has gone well beyond a simple technical prototype - it is a working service being used by astronomers across the world to do science. In April we released Lasair 2.0 (see https://lasair.roe.ac.uk). This is now considered a mature and stable service, which will keep working while in the background we develop and test the next-generation Lasair, for the alerts which will come from the Legacy Survey for Space and Time (LSST) conducted at the Rubin Observatory. For short, we generally refer to the current working service as Lasair-ZTF, and the next generation version as Lasair-LSST.
As the ZTF-alerts stream into Lasair, we add multi-wavelength context, IDs, classification and other added value using our Sherlock software. You can query the accumulating database in various different ways, or produce a filtered stream which is sent on to you. You can also make a "watchlist" of your favourite objects and get alerted when one of them flares up. As well as the web interface, we have a Jupyter interface, which means you can write Python scripts to do all sorts of cunning things. Thanks to the UK IRIS service, there is some pretty high-powered computing facility behind all this. To learn more about what you can do, go the Lasair website (https://lasair.roe.ac.uk), or take a look at the Lasair cookbook (https://lsst-uk.atlassian.net/wiki/spaces/DOC/pages/881360908/Lasair+Cookbook). )
Meanwhile, we have been developing and testing a new and improved version for Rubin/LSST. For Cycles 1 and 2 of our planning process we have been concentrating on technical questions - system architecture, backend database technology, direct Kafka stream handling, and so on. All this was based on the detailed Phase B science requirements. However, as we move into Cycles 3 and 4, our focus will increasingly be on improving the functionality and the user experience. We kicked off this process in June with a kind of focus-group with the core of interested consortium scientists, which was extremely successful and informative. We are also having direct conversations with key projects and collaborations, such as the Zooniverse people, and the TiDES project. However, we are also happy (and indeed keen!) to hear the desires, experiences, and suggestions of any interested users. One of the things we are reviewing right now is how to construct a good helpdesk system - but for now, send your suggestions to lasair-help@lists.roe.ac.uk.
We have a feeling that this process will be about users evolving as well as the project learning - as people get used to the idea of working with streams, as opposed to querying static databases, new ideas will emerge. So we are especially interested in hearing your thoughts on that issue.
Results of JA round
At the end of June, LSST:UK issued a call for applications from potential new Junior Associates. Following a review by the LSST:UK Selection Committee, chaired by Nial Tanvir (Leicester), we are pleased to confirm that 22 new Junior Associates have been approved, plus four existing Junior Associates had their term extended (indicated by *), as follows:
Qasim Afghan (UCL) | Steven Gough-Kelly (Central Lancashire) |
Alba Vega Alonso Tetilla (Southampton) | Noushin Karim (Surrey) |
Marika Asgari (Edinburgh) | Hin Leung (St. Andrews) |
Oliver Bartlett (Hull) | Matt Ratcliffe (Newcastle) |
Matteo Biancoi * (Birmingham) | Agata Rożek (Edinburgh) |
Asa Bluck (Cambridge) | Jaime Ruiz Zapatero (Oxford) |
Umar Burhanudin (Sheffield) | Shubham Srivastav (QUB) |
Matteo Cataneo (Edinburgh) | Paula Stella Teixeira (St. Andrews) |
Cressida Cleland (Birmingham) | Edward Upsdell (sussex) |
Azadeh Fattahi (Durham) | Roy Williams * (Edinburgh) |
Hao Fu * (Southampton) | Tom Wilson (Exeter) |
Carlos Garcia (Oxford) | Bill Wright (QMU) |
Benjamin Giblin * (Edinburgh) | Yirui Zheng (St Andrews) |
First images from LSSTCam
The Rubin Observatory camera team have released a first set of images taken with the full 3200 megapixel focal plane of the LSST Camera, along with a nice account of the engineering challenges faced during the focal plane assembly process. They note that it would take “378 4K ultra-high-definition TV screens” to display each of these images at its full size.
Perhaps most striking amongst the images is that (right) of a head of romanesco - a cultivated form of Brassica oleracea, for the uninitiated - which was chosen as a target because its near-fractal form neatly illustrates the range of scales probed by LSSTCam images, as revealed by playing with the image zoom tool provided by the LSST camera team at SLAC.
Since the camera’s optical system is yet to be integrated, these images were taken through a 150 micron pinhole, and camera team have provided an explanation of some of artefacts visible when you zoom into the images, such as the diffraction patterns from the pinhole.
Credit: LSST Camera Team/SLAC/Vera C. Rubin Observatory
Towards a more Just, Equitable, Diverse, and Inclusive Rubin Observatory
One of the liveliest sessions at the 2020 Project and Community Workshop in August was that entitled Roadmap to a more Just, Equitable, Diverse, and Inclusive Rubin Observatory. Its organisers are hoping to sustain the momentum initiated during that session by running a series of monthly workshops, to contribute to the development of a roadmap setting out the equity and social justice goals of the Rubin community, ahead of the 2021 Project and Community Workshop.
The initial plan is for these meetings - which are open to all - to take place on the first Thursday of each month at 12PM Pacific / 3PM Eastern / 8PM CEST, starting on October 8th. Further details can be found in a posting on the community.lsst.org site.
RAS Meeting: The new window on Transients and Variable Star astronomy with the Rubin Observatory (October 9th)
The first RAS Meeting of the new year takes place online on Friday, October 9th from 10.30-15.30. Its topic is The new window on Transients and Variable Star astronomy with the Rubin Observatory and it is organised by LSST:UK Consortium members Sarah Casewell and Cosima Inserra. Those wishing to attend must register, with separate registration links for RAS Fellows (for whom it is free) and non-Fellows (who must pay £5).
Rubin Observatory Technical Documents Online
For those of you who have not yet discovered it, I would like to point out that the Rubin Observatory maintains a comprehensive repository of technical documents and reports at https://www.lsst.io/. Documentation is categorised into series, based on the particular function or aspect that it relates to, covering technology, engineering, and science. If you ever come across a reference to a Rubin Observatory report of the form DMTN-135 or LSE-61, for example, then it will almost certainly be available from https://www.lsst.io/ (provided it is public). The site usually has some features some topical reports, plus some key document to be aware of include the Rubin Observatory Science Requirements (LPM-17) and the Data Products Definition document (LSE-163).
Recent LSST:UK outputs
LSST:UK has recently produced the following technical reports.
Title | Author | Description | ||
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Bob Mann, Stelios Voutsinas, Roy Williams | This document describes an initial release of documentation for users of current and future services accessed via the UK’s LSST Data Access Centre (DAC). This documentation release is necessarily limited in scope given that the UK DAC is still being developed. It comprises existing documentation for the Lasair alert broker and a very preliminary set of documentation for the LSST Science Platform (LSP). The LSP is the set of data services to be provided by the Rubin Observatory to support analysis of LSST data productsReport on data transfer and ingest experiments for DESC DC2 | Mike Read | This document describes the tests, and their results, undertaken to gain experience with transferring significant volumes of data from a Rubin Observatory processing to the LSST:UK DAC. Such data transfer volumes will be required to acquire each new LSST data release. The tests involved transfers of the DESC DC2 (Dark Energy Science Collaboration Data Challenge 2 from IN2P3 (French National Institute of Nuclear and Particle Physics). | |
Tim Naylor, Tom Wilson | This document describes models deep enough to enable modelling the effect of faint stars at LSST depths. It includes an additional journal-style report that provides further technical details. |