I was born in Adelaide, South Australia, becoming interested in astronomy at the age of 16 in 1986, at the time of comet Halley’s appearance.
My first view of it came in early March through 7x50mm binoculars.
It displayed a beautiful star like nucleus, embedded within a coma, and a dust tail 5 degrees long, looking directly over the city of Adelaide.
Today the same feat would be impossible with the city light pollution now so severe.
I was very fortunate to observe the comet from a dark sky site for the first time, at closest approach on 1986 April 11.
Not only could I see the comet and 5 degree tail easily with the naked eye, but the milky way also stood out in all its glory.
The scene had me hooked and I was determined to find a comet of my own.
I joined the astronomical society of South Australia in 1990 and had the privilege to know one of the greatest visual comet hunters of all time.
Bill Bradfield, discoverer of 18 comets, was my mentor and gave me much support. The only problem I had was dealing with Adelaide's light pollution.
I had the chance in 1997 when I took up a position of pathology lab manager in Wallaroo, a small town in country South Australia.
The dark skies were perfect and that’s when I started observing and hunting for comets.
Using an 8” telescope at the time, I narrowly missed out on finding comets Lee and Lynn.
In July 2000, I purchased a pair of 25x100mm binoculars.
On the night of November 24, 2000, I swept up a bright 7th magitude object in Ara, that wasn’t a known comet.
I reported this to CBAT but later found I was pipped at the post, by Albert Jones in NZ, who had picked it up 24 hrs earlier.
The comet was announced as C/2000 W1 Utsunomiya-Jones.
SWAN COMET HUNTING
In 2002, the first SWAN comet was announced. C/2002 O6, discovered by Japanese observers.
SWAN stands for Solar Wind Anisotropies, an experiment on board SOHO spacecraft, developed in collaboration with Finnish Meteorological Institute
The SWAN camera can pick up comets quite easily via the ultraviolet emission of Hydrogen in the coma.
At the same time the project team started to offer their data in “comet tracker map” form.
I gave up visual comet hunting in favour of confirming SWAN comets, as it was capable of detecting comets as faint as 12th magnitude,
The first object I picked up was in April 2003, but no one was able to confirm it on the ground until a month later when Eric Christensen of the Catalina Sky survey discovered it.
This short period object is now called 210P Christensen but should have been labelled as SWAN-Christensen.
First success came in May 2004 with the detection of C/2004 H6 SWAN
It was a great sensation to be the first person in the world to visually observe the comet, just a few degrees above the evening horizon, using 25x100mm binoculars.
Unfortunately the comet was approaching solar conjunction and I had to wait a further week, before reconfirming it in the morning sky.
Part of the problem was trying to convince CBAT that the comet was real, since they were receiving numerous never confirmed reports of SWAN comets.
I had to send them an image of the comet,with tail, as proof.
As of December 2015, I have discovery credit for 7 other SWAN comets, C/2004 V13, C/2005 P3, P/2005 T4,
C/2006 M4 (the brightest one reaching 4th magnitude), C/2015 C2 and C/2015 P3
There are currently 15 comets carrying the SWAN name, with fierce competition amongst SWAN comet hunters.
Other successful SWAN hunters include Robert Matson and Vladimir Bezugly.
DISCOVERY OF C/2015 P3 SWAN
On 2015 Aug 9 at 03UT, I downloaded the latest SWAN comet tracker maps at http://swan.projet.latmos.ipsl.fr/
and noted a suspicious object located on the Leo-Coma Berenices border on images dated Aug 3 and 4.
I measured very approximate positions on these dates, as well as a possible earlier detection on July 28:
Position accuracy is generally in the order of 1 to 2 degrees of sky.
Since the comet tracker maps are posted with a time delay of nearly a week, I had to predict where the comet may have advanced in the sky.
I covered a 10 degree square patch of sky in Virgo, situated around Rho Virginis that evening, at 09:11UT, and confirmed the comet photographically after the third sweep,
using a Canon 60Da + Sigma 200mm F/2.8 lens, tracking on a Vixen polarie star tracker.
The comet appeared slightly condensed, of photometric magnitude 11.8, with a coma diameter of 2 arcminutes.
The blue green colour of the comet stood out from the white appearance of the Virgo supercluster of galaxies.
Rapid motion was evident as I imaged the comet for the hour following discovery.
I measured its positions using Astrometrica software and sent it through to CBAT for posting on the Possible Comet Confirmation page.
The discovery was announced on CBET 4136 and the comet designated C/2015 P3 SWAN.
The preliminary orbit indicated that perihelion had already occurred on 2015 July 27 at 0.71AU.
The comet was not expected to become much brighter than magnitude 11.
It was very faint intrinsically (mag 14) and I'm surprised it even survived perihelion.
But a clue lies in its revised orbit - it is a dynamically evolved object, orbiting the Sun every 3,000 years.
SOUTHERN COMETS WEBSITE
The idea of setting up this webpage came about in 2002, after I had observed the spectacular outburst of C/2000 WM1 LINEAR, erupting from magnitude 6 to 2.
Through 25x100mm binoculars, the starlike nucleus had 2 jets "horns" emanating at opposite poles of the nucleus. The view was reminiscent of classical drawings of the past.
Since then, I have been documenting every bright comet that I have had the fortune to observe from my perspective in the Southern Hemisphere,
including the great comets C/2006 P1 McNaught and C/2011 W3 Lovejoy.
Regarding the latter object, Terry Lovejoy had sent me his discovery positions in an attempt to confirm it, of which I then proceeded to add into Guide software.
I also simulate Kreutz sungrazing comets in my software as I search along the Kreutz line (as reccommended by Bill Bradfield).
As it so happened, I had a simulated sungrazer programmed in, with a perihelion date of December 15.
Lo and behold, Terry’s positions matched exactly to within a few degrees of this simulation, showing the same speed and direction as the Kreutz comet.
It was a eureka moment knowing that his find was a member of the Kreutz group after just 2 sets of observations!
MY TELESCOPE SETUP
Telescope: Celestron Nexstar 11 GPS
Camera: Starlight Express MX7c CCD, one shot colour 752x582 pixels, resolution of 1.9" per pixel at f/3.3 with C11 setup.
Digital Camera: Canon 60Da + Sigma 70-200mm f/2.8 lens.
Telescope control: Guide 9 software
Image Processing: Maxim DL6
Observatory codes used: Q38 Swan Hill, E00 Castlemaine, D87 Brooklyn Park, D82 Wallaroo, 427 Stockport.
I currently reside in Swan Hill, Victoria, Australia.