Category Archives: Research

Set back due to the storm

As most people would know now, there was a big storm on Saturday, which also hit the Ardmore area. There was even a picture on the NZ Herald of a couple of light aircraft being flipped over from the wind in the Ardmore airport. I was actually planning on going out there that day to look into changing some things with the equipment to see if it improves the detection of signals, but needless to say, the weather changed my plans. Since then, I haven’t been able to remotely access the computer, so I was left in the dark for the rest of the weekend about whether there was any damage to my antenna or any of the other equipment.

Taken from the NZ Herald article Ardmore Airport. Photo / Matt Archer

Taken from the NZ Herald article
Ardmore Airport. Photo / Matt Archer

After my classes on Monday, I made the decision to go there to see if everything was okay. Not knowing if my antenna was still in one piece stressed me out, so I needed to see for myself if there was any damage, calm my thoughts and decide what my next step should be. Luckily, everything seemed to be working and the antenna is still in its place! However, there was a problem with the computer and internet access, because the storm caused a power cut which lasted a few hours, and the back-up power source for the internet ran out of battery during that time, so it didn’t start up again after the power came back on. I restarted it, but I still couldn’t manage to access the computer remotely from my laptop.

I sent an email to the person who helped me set up the computer in the first place and hopefully he’ll be able to find some time over the next couple of days to go there and help me fix the problem.

I’ve been thrown off a little bit by the storm, but I couldn’t predict something like this. I just have to be positive and hope that although it’s a little set back, it seems to be something that can be fixed quickly and easily, so I’m hopefully still on track and will have everything going to plan soon!

My Honours Project

Hi there! So since this is my first blog post, I should probably introduce myself before I write anything else.

I’m Ana and I’m currently doing my Honours degree in physics. I have just graduated with a Bachelor of Science, majoring in physics and maths and decided to pursue an academic career in physics.

My project for this year is to detect meteors using forward scattering of radio waves off meteor trails. Instead of building a dedicated radio receiver specific for this project, I decided to use Software Defined Radio (SDR). Basically, this means building an antenna, connecting it to the SDR and setting up a software to detect a radio wave that I normally wouldn’t detect as the transmitter is beyond the horizon. When a meteor enters the atmosphere, it creates a trail of ionised air, the radio wave reflects off this trail, and thus it can be detected.

Since this project was started from scratch, I divided my main goal into smaller goals:

  • choose a frequency that I was going to look for
  • buy a receiver
  • find a computer
  • find the software I would use
  • build an antenna
  • set it all up
  • enable remote access to the computer

The system is set up at Ardmore Field Station, in South Auckland so the remote access was necessary so that I wouldn’t have to drive out every day. I had help from a couple of technicians in the physics department with getting the materials for the antenna and with building it, and I had help from IT services when it came to setting up the computer, installing the software and enabling the remote access. At the moment, I am also getting help from my dad with the plugins that had to be added to the software to record the signals, as the currently available plugins online weren’t what I needed.

Here are a couple of progress photos from when the antenna was being assembled:

Putting the elements together

Putting the elements together

One of the technicians working on the dipole

One of the technicians working on the dipole

The dipole

The dipole

The final set up of the antenna

The final set up of the antenna

Currently, as my project stands, I chose the frequency 101.7 MHz from Christchurch, the receiver is Airspy and I am using the software SDR# to detect and record any signals that my antenna picks up at that frequency. So far, I have detected some signals, but these don’t seem to have the power spectrum that a signal that has been reflected off a meteor should have. Based on my readings and what other people have done in the past, there are a few power spectra that I should get depending on how big the meteor is. However, I’m either not interpreting the signals correctly, or these haven’t been reflected off any meteor trails. For reference, please look up “Forward Scattering of Radio Waves off Meteor Trails” by Jean-Marc Wislez, or look at this website since its information mostly came from that research paper.

I started to think that maybe the power at which my frequency is being emitted isn’t strong enough to be detected upon reflection, so I have just tuned into another frequency that’s stronger and I’m waiting to see if my antenna picks anything up. From what I’ve read so far, I’m expecting the biggest meteor count in the hours between midnight and 7am, and the least count should happen in the evening hours (Refer to this website).

The main aim at the moment is to have this whole set up working and detecting by the time the Perseids meteor shower happens, which is only a few weeks away. The peak this year will be at around the 11th of August. I will know that my set up is working if even before the meteor shower I am getting the expected power spectrum, and the expected rate of meteors (most over night and little during the day). The Perseids should be the biggest confirmation of my set up working and it should also be when I collect most of my data to analyse and write about in my dissertation!

I’ll follow up with more posts with updates and/or if I remember anything important I’ve done that I forgot to mention.

Until next time,
Ana

Networking (the computer kind) for Non-Network Engineers

This week’s seminar was presented by Charles Yun and Jeff Weekley, of REANNZ (Research and Education Advanced Network New Zealand Ltd) which runs the network infrastructure between research institutions such as universities.

Their remit is to make sure that data can be passed between research institutions quickly, and not using the same pipeline as commercial internet — i.e, the pipes channelling youtube videos of kittens.

This was of particular interest to me, as I recently tried to copy 2.5Tb of data from Massey Albany to Auckland Uni. This took far longer than it should have. It was almost going to be more convenient to drive out there with a hard disk and wait for an hour or two for the data to copy, then drive back.

image003

Here are Charles’ and Jeff’s talks:

REANNZ colloq talk-but i am not a network engineer (Charles’ talk)

REANNZ.Weekley.HighSpeedFileTransfer (Jeff’s talk)

MJUO 50th Anniversary Symposium

As Dr. Rattenbury has already mentioned in a previous post, the golden anniversary of the Mount John University Observatory (MJUO) was celebrated this year. I was fortunate to have been given the opportunity to attend and absorb the individual experiences of the astronomers.

The symposium’s theme centered around the observatory’s past, present and future. What I found most charming were the many stories told by astronomers who have become part of its history and who have had MJUO become an important part in their own lives in return.

Many times it felt like I was being transported to a cozy chair by a fireplace with grandpa recollecting the fascinating stories of his life, the adventures he had as an astronomer.

Here are only some of the many interesting things I heard during the symposium.

Audrey Walsh reflected upon her father, Frank Bateson’s work in establishing MJUO. Frank Bateson is the father of NZ astronomy, is has been said. In his own words, he was a “businessman by profession, astronomer by nature”. Hearing these words was an extremely inspiring moment for me, for it brings to my mind the image of a man who was passionate about his work.

Ed Guinan gave an entertaining account of the adventures and misadventures he had during the year he spent at MJUO and NZ in general. It was disheartening to hear that a chart of his results, which he kept close to him instead of shipping it, out of fear of losing it, was after all lost to the USSR customs while travelling through Russia.

The talk given by Alan Thomas painted a vivid picture of the contrast between observational astronomy as it was done all those years ago and how it is done now. Part of the excitement then was enduring the cold of the nights, snuggled up against a telescope in the open, in a sleeping bag, with a hot beverage, looking through the eye-piece.

Graeme Kershaw’s talk highlighted the fact that many countries have lost contact with the night sky so that lots of people come to lake Tekapo just to see the stars. He also pointed out the growing frustration of the elderly who grew up gazing up at the stars but can not offer the same to their children.

Many other talks painted similar pictures and drove it home that MJUO is one of the world’s most beautiful and easily accessible telescopes, rich with history and memories of individuals.

I have come out from this celebration with a refreshed aspiration for astronomy!

Watching SkyWatch

Just had a very interesting chat with some of the folk at http://skywatch.co/. They are interested in collecting information about astronomical transient data and making that information available real-time to anyone who wants it, in a standardised format.

They started off with the GCN, the network that disseminates information about gamma-ray bursts from space satellites, to ground based observatories. But they are looking to expand:

skywatch

But GCN is just one of many networks. So we continued to build…

And they are talking to astronomers about their data, what they collect, and how SkyWatch can help.

PhD update

An important part of provisional year of PhD candidacy is to refine one’s research question.

While I wrote an evolutionary algorithm code as an optimization method to search the high dimensional parameter space of the microlensing modelling problem, I have been faced with the tough decision to place it on the sideburner while diving into a new area of investigation for the purpose of refining the research question further.

This was due to the literature findings that suggest that microlensing model comparison techniques are in need of development, beyond the comparison of chi-square values alone!

This new direction of investigation involves Nested-sampling based algorithms for simultaneous parameter estimation and model comparison, based on the Bayesian approach.

19th Annual Microlensing Conference

Annapolis is a pretty city, and played host to this year’s annual microlensing conference. Our host was Dr Rich Barry, Goddard Space Flight Centre.

There were a lot of interesting talks, planet discoveries and techniques being a primary focus, but with a strong influence coming from the proposed space telescope missions which may include microlensing observations in their additional science programmes.

There are two space telescope missions are ESA’s Euclid and NASA’s WFIRST/AFTA. Both are exciting missions. I contributed in a small way to the proposal to use Euclid for planetary microlensing. The last piece of work I did at Manchester was to write code to simulate microlensing observations, to estimate how many planets a space telescope could find, and of what type. I never finished that code, but it was taken over by Matthew Penny at Manchester as part of his PhD work, and he turned it into an excellent piece of software. Matt wrote an excellent paper on it.

It was great to catch up with Matt, and lots of other microlensers at the conference. Ashna Shara (my PhD student) was also there, to get to know the field, meet the people, and try to refine the topic of her PhD.

I gave a talk on — not microlensing — but on a piece of work that uses the large databases that the microlensing survey teams have accumulated. Next conference I hope to have something more on planetary microlensing!

linux.conf.au

This year’s linux.conf.au meeting was held in Auckland, at the University of Auckland’s Business school.

There was an astronomy miniconference held during the main meeting. JJ Eldridge and Pauline Harris (Victoria) gave awesome talks, as did my PhD students Ashna Sharan and Alex Li and MSc student Martin Donachie. I was in the happy position of being able to introduce these able students and the work they are doing with me, leaving me to pontificate about other things.

All the talks were recorded, and edited for your viewing pleasure. They are available at http://mirror.slingshot.co.nz/pub/linux.conf.au/2015/Case_Room_2/Tuesday/.

It was a great event, and a great crowd. I didn’t expect to be talking to a packed room! All credit to Jessica Smith for organising the miniconference!