Microlensing 22 will be held in Auckland, January 2018


The next annual microlensing conference will be held in Auckland, New Zealand on January 25th to 28th, 2018. This announcement is so that you can save the dates in your calendar. The first full announcement will follow shortly.

This meeting is the 22nd in the series of international conferences on microlensing and will include topics such as:

  • Planet detection by microlensing from both ground and space,
  • Latest theoretical and observational advances,
  • Predictions and proposed answers to current challenges
  • Tensions in exoplanetary science and how microlensing can address these.

The SOC for Microlensing 22 is

Rachel Akeson (Caltech/IPAC)
Valerio Bozza (University of Salerno)
Scott Gaudi (The Ohio State University)
Calen Henderson (Caltech/IPAC)
Jessica Lu (University of California Berkeley)
David Nataf (Johns Hopkins University)
Nick Rattenbury (University of Auckland)
Rachel Street (Las Cumbres Observatory)
Takahiro Sumi (Osaka University)
Andrzej Udalski (Warsaw University)

We look forward to seeing you in Auckland!


The Microlensing 22 SOC

A Visit to CalPoly to learn how to build CubeSats

The California Polytechnic State University — CalPoly — is in the pretty town of San Luis Obispo, a four hour drive north-west of Los Angeles. It is the home institution of one of the two academics who defined the CubeSat small satellite form factor. Every year CalPoly hosts a conference bringing together academics, industry, educators and students who are eager to use the CubeSat technology as a cheap way of conducting a space mission.  This year’s conference was the 14th in the annual series and was the most well attended to date, with around 300 attendees.  Around half of the audience was from academia or other educational institutions and the other half from the aerospace industry. The three of us who attended constituted one of the largest delegations from a foreign university.

The CubeSat standard has produced an industry providing CubeSat format compatible satellite subsystems — most of which are advertised as being “plug and play”. However of course the reality still is, as they say, space is hard. Space is also expensive.  For these reasons we need to learn as much as possible how to design, construct and test small satellites. It’s well-known that, after over a decade of launching CubeSat space missions, around 50% of those launched from student teams do not function upon arrival in orbit. The reason for this is usually attributed to a failure to test the satellite sufficiently well before launch. Our tasks at the conference was, therefore,  to listen, learn and talk to as many people who we think would be able to advise us as we start on this perilous journey into space. We had the opportunity to listen to many speakers on their experiences launching CubeSat based space missions.  Some of the talks were from industry-based enterprise and some from academia and indeed some from high schools. The advantage of a CubeSat is that it is a  relatively cheap platform around which to base a space mission.  They are small and therefore are usually modest in the scientific returns.  However they can be designed and constructed at relatively low cost and relatively quickly. This allows CubeSats to take advantage of technological innovations at a far greater rate than traditional large space missions. By the time a traditional large space satellite is launched the technology is already some years out of date as engineering requirements would have had to be specified and set in stone some years before launch.  This is not the case with nanosatellites such as a CubeSat, indeed some of the first  small satellite missions simply flew a commercial cell phone into orbit, the so called PhoneSats.

We were able to talk to several people who are a particular interest in our work with the APSS. Brad Schneider (VP/General Manager Rocket Lab USA) was there and we had a good chat with him.  Brad was able to update us on the status of Rocket Lab’s operations at their launch site at Mahia, as well as giving us an idea of the scale of Rocket Lab’s operations in the US. We also caught up with the CEO of Clyde Space, Craig Clark, MBE. Clyde Space is supplying our first CubeSat system, functional and ready to incorporate a small student payload. We found Craig to be very supportive of our new programme and stands ready to help us out as far as possible.

NASA has long recognised the value of small satellites and indeed CubeSat space missions as a means for demonstrating new technologies quickly and relatively inexpensively. There were a number of topics of interest in small satellite technology development expressed at the conference.  One of the biggest challenges to small satellite space missions is the inability to transfer large amounts of data collected in space down to Earth.  Power restrictions and bandwidth often mean that the data downlink from satellite to Earth is somewhat modest.  There is therefore a great deal of interest in optical communication systems which could allow small satellite space missions to download more of their data.  One of the most ambitious programs of this type is to perfect a system of laser communication between a small satellite and a telescope on Earth.  The predicted maximum data rate is expected to be of the order of a gigabit per second.  Other technology challenges which are being currently addressed by the community include propulsion systems for small satellites. This is of particular interest as small satellites are being considered for missions well beyond low earth orbit.  Missions are being designed to travel to Mars and the moon.  Finally as an example firmly in the realm of cutting edge technology, there is a program being run by the University of Singapore to enable Quantum Key Distribution. QKD is a technique which, if successful, will utilise the phenomenon of quantum entanglement to improve encryption. Satellites will generate entangled photons and distribute these to the well-known correspondents Alice and Bob. Essentially creating a one-time pad, QKD offers a means by which that miscreant Charlie will be fresh out of luck in eavesdropping on their conversation. There is therefore a great deal of opportunity for universities and research institutions to develop small satellite subsystem technology.  Nanofluidics, biological experiments, laser communication, material science,  computer algorithm design, were all the basis of small satellite enabled missions described at the conference.  Apart from work developing new technologies is the drive to miniaturise current technologies to operate on a small satellite. Delwyn Moller (Principal Systems Engineer, Remote Sensing Solutions and UoA Engineering alumnus), at a talk given at the UoA earlier this year, mentioned that her company is working on miniaturising their radar system to fit within a CubeSat.

There is, therefore, a great interest in the community in developing technologies for flight on CubeSats. These subsystems are necessarily small and will have a very high cost per kg, ideal for a country like New Zealand, remote to most major consumers of small satellite technologies. There are significant research programmes at the UoA that could take part in developing CubeSat technologies, including the laser and quantum optics groups in the Department of Physics; the robotics, electronics, mechatronics groups in the Faculty of Engineering.

And in addition to this there is always the opportunity to use small satellites to engage students in STEaM subjects at university, in the way that we are doing with the APSS.  There were a couple of talks at the conference which described the work done by university and high school CubeSat based programmes. One of the more impressive outfits is Auburn University, which has been running a small satellite programme for some time. They note that the advantages of the programme include the excitement space brings to the student environment, as well as a sense of community. Challenges include the maintenance of motivation of the students as well as the time expended and the continual loss of “corporate memory” as students pass through the programme. Motivation is heightened by a sense of ownership, which is in turn maximised by a degree of autonomy. A feature of this programme is that the students are divided into management teams and technical teams, depending on their skill sets.

The Vice President  (Engineering) of AMSAT was present at the conference and demonstrated how easy it was to listen to the AMSAT satellite as it passed overhead on day 2 of the conference.  One of us (NJR) forced the others to suffer rush hour LA traffic to get to an amateur radio shop in Anaheim to buy an antenna rotator, which will be an integral part of a UoA satellite ground station.


Nicholas Rattenbury

John Cater

Jim Hefkey


May 2017

NJR Honours Projects for 2017

Here’s my list of Honours projects for 2017. If you are keen to do one of these, please email me or drop by to discuss.

1. Construct a Satellite Ground Station

In 2018, the University will start to launch CubeSats into low earth orbit. We will need a ground station to communicate with our satellites. The project will require the student to construct an antenna system comprising a software defined radio, corresponding control and analysis software, and display the information in a suitable format. This work will be done in conjunction with the Auckland Programme for Space Systems, using the new APSS laboratories on Symonds Street and the Department of Physics Electronics Laboratory.

Listen and track satellites and help us get ready for launch in 2018!

Listen and track satellites and help us get ready for launch in 2018!

2. Get into Machine Learning and classify Supernovae (in conjunction with JJ Eldridge)

This project will involve training a machine learning algorithm to classify standard supernovae lightcurves. The work will then be to see how the classifier copes with rarer, non-standard supernovae light curves, adapting the learning algorithm to correctly classify these non-standard curves as well. This work could then be extended to be part of the Transient and Variable Survey work of the Large Synoptic Survey Telescope (LSST), making predictions on how well the LSST will discover these rarer supernovae light curves.

Classify rare and exotic supernovae using machine learning!

Classify rare and exotic supernovae using machine learning!


3. Astronomical Seeing Measurements in the Greater Auckland Area.

One of the Department’s 40 cm Meade telescopes has been converted into a seeing monitor. Seeing is a measure of atmospheric turbulence. This project will involve the student making seeing observations at various sites in the Greater Auckland area, analysing the results and publishing these. The student will have to be comfortable working at night, and have a full driver’s licence.

Use one of these!



4. Multidimensional Dataset Visualisation with an Oculus Rift

This project will require the student to investigate the software available for displaying multidimensional datasets using an Oculus Rift. The key objectives are to have a suite of software tools available to allow a user to navigate complex multidimensional data via virtual reality immersion. Students should have a high level of programming ability.

Oculus Rift DK2


5. Detecting Atmospheric Meteor trails

Meteors entering the Earth’s atmosphere leave a trail of ionised particles. We have a software-defined radio system set up to detect radio signals from Christchurch which are forward-scattered off these trails. This system is working successfully, but can be improved upon. The honours project will comprise optimising the system to improve the number of detected meteor trails, to compile statistics of this year’s meteor showers and report them to the International Meteor Organisation. The project would also comprise making the observed data available via the Internet in real-time.

Analyse these!

6. Design a CubeSat to perform Synthetic Aperture Radar measurements

With the Auckland Programme for Space Systems starting here at the University of Auckland, we are beginning to think about how New Zealand can benefit from utilising space. This project will be to design a synthetic aperture radar system that can be carried on a CubeSat (a 10x10x10 cm) satellite. Careful attention will need to be paid to power budgets, communication bandwidth budget and of course mass and volume budgets. Some experience in electronics would be an advantage.

Design a CubeSat!

Microlensing Study Suggests Most Common Outer Planets Likely Neptune-mass


Gravitational microlensing is a method for discovering extra-solar planets. It is different to other techniques in that it is sensitive to planets in orbits around their host star where scientists think planets form most readily. In a recent work, Daisuke Suzuki of the Japan/New Zealand MOA collaboration announced that the most likely mass of such planets is about that of Neptune. The story was picked up by the New Zealand Herald today.

This graph plots 4,769 exoplanets and planet candidates according to their masses and relative distances from the snow line, the point where water and other materials freeze solid (vertical cyan line). Gravitational microlensing is particularly sensitive to planets in this region. Planets are shaded according to the discovery technique listed at right. Masses for unconfirmed planetary candidates from NASA's Kepler mission are calculated based on their sizes. For comparison, the graph also includes the planets of our solar system. Credit: NASA's Goddard Space Flight Center

This graph plots 4,769 exoplanets and planet candidates according to their masses and relative distances from the snow line, the point where water and other materials freeze solid (vertical cyan line). Gravitational microlensing is particularly sensitive to planets in this region. Planets are shaded according to the discovery technique listed at right. Masses for unconfirmed planetary candidates from NASA’s Kepler mission are calculated based on their sizes. For comparison, the graph also includes the planets of our solar system.
Credit: NASA’s Goddard Space Flight Center

To reach this conclusion, Suzuki and his co-authors analysed a set of microlensing planets that have already been discovered, conducting a statistical analysis to infer the most likely planet mass of these cold planets. One of the planets included in the planet which I announced in Monthly Notices last year. The discovery and announcement of these planets power the sort of statistical analyses like that of the Suzuki et al result.

Neptune-mass exoplanets like the one shown in this artist's rendering may be the most common in the icy regions of planetary systems. Beyond a certain distance from a young star, water and other substances remain frozen, leading to an abundant population of icy objects that can collide and form the cores of new planets. In the foreground, an icy body left over from this period drifts past the planet. Credit: NASA's Goddard Space Flight Center/Francis Reddy

Neptune-mass exoplanets like the one shown in this artist’s rendering may be the most common in the icy regions of planetary systems. Beyond a certain distance from a young star, water and other substances remain frozen, leading to an abundant population of icy objects that can collide and form the cores of new planets. In the foreground, an icy body left over from this period drifts past the planet.
Credit: NASA’s Goddard Space Flight Center/Francis Reddy

Story: https://www.nasa.gov/feature/goddard/2016/most-common-outer-planets-likely-neptune-mass

Paper: http://iopscience.iop.org/article/10.3847/1538-4357/833/2/145

arXiv version of paper: http://adsabs.harvard.edu/abs/2016arXiv161203939S

Additional graphics: http://svs.gsfc.nasa.gov/cgi-bin/details.cgi?aid=12425

Video on YouTube: https://youtu.be/qzlR3kBCLYM

Wide-orbit planet discovered around binary star with MOA-II and HST

From the press release from the Space Science Telescope Institute:

Astronomers using NASA’s Hubble Space Telescope, and a trick of nature, have confirmed the existence of a planet orbiting two stars in the system OGLE-2007-BLG-349, located 8,000 light-years away towards the center of our galaxy.

The planet orbits roughly 300 million miles from the stellar duo, about the distance from the asteroid belt to our sun. It completes an orbit around both stars roughly every seven years. The two red dwarf stars are a mere 7 million miles apart, or 14 times the diameter of the moon’s orbit around Earth.

The Hubble observations represent the first time such a three-body system has been confirmed using the gravitational microlensing technique. Gravitational microlensing occurs when the gravity of a foreground star bends and amplifies the light of a background star that momentarily aligns with it. The particular character of the light magnification can reveal clues to the nature of the foreground star and any associated planets.

The three objects were discovered in 2007 by an international collaboration of five different groups: Microlensing Observations in Astrophysics (MOA), the Optical Gravitational Lensing Experiment (OGLE), the Microlensing Follow-up Network (MicroFUN), the Probing Lensing Anomalies Network (PLANET), and the Robonet Collaboration. These ground-based observations uncovered a star and a planet, but a detailed analysis also revealed a third body that astronomers could not definitively identify.

Source: Hubblesite.org

Check out the video describing gravitational microlensing and the discovery!

Doubly eclipsing binaries

It is nothing special, but I have discovered several doubly eclipsing binaries in MOA database. The figure below is one of them. It was achieved by first substracting the mean light curve with 200 bins from the one folded with P=0.409d and then redoing the period analysis to see if there is any hidden periodic variation.


Funded MSc Thesis — 2017 — Virtual Reality Data Visualisation

I have funding available (one year, domestic) for an MSc student to develop our capacity to visualise multi-parameter datasets using virtual reality. The full advertisement is below. If you are interested, please get in touch.

Oculus Rift DK2 Oculus Rift DK2

The Department of Physics, in collaboration with the Intelligent Vision Systems Team in the Department of Computer Science, has funding available for an MSc thesis student to develop tools for the visualisation of multi-parameter data sets using virtual reality. The student will continue to develop existing prototype code to improve our capability to interrogate data sets using an Oculus Rift. Data from the fields of astronomy, cosmology and drone flights are available to test and improve the codes used. The student will also investigate the use of hand gesture control as part of an improved human control interface with the analysis codes. Some programming experience is required. The funding for this project comprises one year’s MSc (domestic) fees.


I’ve become a fan of Plot.ly — an online service for plotting data and sharing it. I was mainly interested in figuring out how to plot my useage of the NeSI PAN cluster computer — particularly for seeing how many computer nodes I was using at any given time, and how many jobs were left to do. I found that with Plot.ly you can stream data to their server and it will update a plot as the new data come in. Their tutorials for setting this up are reasonably straightforward, and I managed to write a little python code to stream the state of my jobs on the cluster (with a little help of crontab and scp):

Link to live streaming plot.

Screenshot from this afternoon: