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 Dob before I became a poor PhD student. I added Argo Navis digital setting circles a couple of years later. I think I caught what astronomers call "aperture fever" and now I own a 16" 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 was the Training Officer for most of 2000-2016 apart from being Chairman during 2011-2012. I've taught many 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.
My PhD research 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). You can read it for free here.
I got my PhD in 2005.
I was elected a Fellow of the Royal Astronomical Society in 2006.
I have dabbled in a little bit of cosmology research with John Jackson (my PhD supervisor). You can see the results of that here.
I trained to be a Mathematics teacher at Newcastle University and worked in a high school in Northumberland for two terms. I have been a Maths Tutor on the Foundation Programme at INTO Newcastle University since April 2008. See my maths website here.
One of my images of the Venus transit in 2004 was featured in Patrick Moore's book "Sky at Night: Answers to Questions from Across the Universe". One of my Mercury transit images made it into the Journal for the Association of Lunar and Planetary Observers (the issue can be downloaded here: Vol 45, No 2, Spring 2003).
For the last two years I've been writing a maths text book for international students. The first edition, in two volumes, has been printed by Pearson publishing. I'm now writing an astronomy book with a working title "Birth Stars".
I've been interviewed about astronomical events on local TV and radio (Alnwick's Lionheart Radio, BBC Radio Newcastle) and nationally on BBC News, Look North and BBC Radio 4 and Five Live.