I have been an astronomer since.....well, I can't remember exactly when. I remember a close conjunction of Jupiter and Saturn and a total lunar eclipse in the early 1980s but I was already hooked on astronomy by then. My first telescopes were disappointing small refractors promising big magnifications. My first proper telescope was a 6" Coulter Dobsonian imported from the US. What I saw through this caused me to upgrade to a 10" Callisto Dobsonian before I became a poor PhD student. I upgraded again in 2007 to a bigger telescope: a 16 inch Meade LightBridge.

I'm interested in most aspects of astronomy and mathematical astronomy, image processing and cosmology in particular. In 2005/6 I was investigating a cosmology problem; using milliarcsecond radio sources to measure the matter and energy content of the universe (Jackson and Jannetta 2006).

I am a member of Northumberland Astronomical Society and held the position of Training Officer since 2000. I've taught seven 10-week courses and presented numerous talks on a variety of topics at general society meetings. I'm actively involved in the society's astronomy outreach sessions in the local community. In 2009 I’m presenting a session at the Centre for Life in Newcastle.

Research interests

My PhD research is involved applying existing methods of dealing with ill-posed inverse problems to the restoration of digital X-ray images. I'll briefly describe the results of my research here...

Magnification mammography is method of obtaining images of breast tissues using projection radiography. In the conventional set-up the x-ray source is made as small as possible ('fine focal spot') to minimise blurring on the image receptor and the geometric magnification is usually around 1.8x. A broad focal spot would allow shorter x-ray exposures to be used (good for the x-ray tube) and blurring caused by patient movement would be less likely. However, the blurring introduced by using a larger focal spot would ruin the image quality. I have therefore been exploring deconvolution techniques - particularly Maximum Entropy - as a means of improving the situation in the unconventional broad focal spot setup, as well as in the usual magnification mammography setup. Other experiments have involved trying to de-blur images obtained using higher than standard geometric magnifications and maintaining image quality when Poisson noise degrades an image at lower than conventional doses.

Tomography is a branch of radiography which uses motion of the focal spot and image receptor to illicit depth information from an object. The simplest motion is linear and leads to the planar slices of linear tomography. Using this technique only a single plane remains in sharp focus on the image receptor while features above and below are smeared out, blurred and removed from visual consideration by the eye-brain system of the observer. The blurring associated with linear tomography is considerable; my research involved modelling the forward map of the tomography system and modifying maximum entropy algorithm accordingly. Images processed with my method showed a substantial reduction in out-of-plane blurring.

A paper based on some of my magnification mammography research was published in the IOP journal Physics in Medicine and Biology (Jannetta et al 2004).

I passed my PhD in July 2005. I trained as Maths teacher in 2006/7 and obtained a PGCE. I worked for two terms as a teacher in a local secondary school before moving on to my current role as a Maths tutor at INTO Newcastle University, where I’m a coordinator for the Science and Engineering mathematics modules.

Random Stuff

One of my Mercury transit images was featured in the journal for the Association of Lunar and Planetary Observers (the issue can be downloaded here: Vol 45, No 2, Spring 2003).

I've been interviewed about astronomical events on local radio (Alnwick's Lionheart Radio, BBC Radio Newcastle) and nationally on BBC Radio Five Live.

I am currently studying The Calculus of Variations module, which will count towards a MSc in Mathematics with the Open University.

The love of my life is Emma...you can see how talented Emma is by visiting her websites.
 

Space Art

One of the first books I enjoyed as a young astronomer was William K Hartmann's "Traveller's Guide to the Solar System" which has many artistic renditions of scenes from the surfaces of other planets and moons in the solar system.  I was always impressed by the beauty of those pictures and by how Kaufmann's imagination constrained those pictures using scientific knowledge of the day.  Other memorable artists include David A Hardy and Paul Doherty.

I can't draw - I wish that I could!  I generated the images in on this page using a combination of software:  Celestia to depict the sky and Terragen to render the local landscapes.  Not a patch on the art that inspired me many years ago but still very enjoyable to imagine what it would be like to see these places for real!

Here is a link to my personal website:

Web Designer: Emma Jane Maddison

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