http://www.skyandtelescope.com.au 11Largelensesforlargesurveys
One of the world’s largest astronomical lenses has been made
in New Zealand, destined for the William Herschel Telescope
in the Canary Islands. The 1.1-metre-diameter lens is one of six
beingfabricatedforthe6-elementprimefocuscorrectorforthe
telescope’snewWEAVEmulti-objectsurveyspectrograph.
WEAVEwillbeusedtoconductalarge-scalesurveyoverfive
yearsof10millionobjects,suchasgalacticstarsanddistant
extragalactic sources.
ThelensesaretheworkofWellington-basedKiwiStarOptics,
aunitofCallaghanInnovation,NewZealand’sinnovationagency,Parkes gets new ‘bionic ear’
A$2.5MILLIONinstrument developed
byCSIROandaconsortiumof
Australian universities will give the
Parkesradiotelescopetheabilityto
covermorefrequenciesasitlistensfor
faintradiowavesfromspace.
The new receiver covers the spectrum
from700MHzto4GHzanddoesthe
work of several extant receivers, as well
as covering extra frequencies.
“Starsandgalaxies‘sing’with
different voices, some high,
somelow,”saidCSIRO
astronomer Dr George Hobbs
said.“Untilnowwe’vehad
receivers that heard just one
partofthechoiratatime.This
new one lets us listen to the
whole choir at once.”
Continuous upgrades have
givenParkes10,000timesmore
sensitivity that it had when it
wascommissionedin1961.And
thebeautyofthenewreceiver
is that it will enable severalwhich specialises in precision astronomical optics.
“We bring the glass over from the USA, Japan or Germany and
then it is milled into shape using our 5-axis CNC mill. Once in shape
the lens goes through a series of shaping and polishing processes to
get it within 1 micron of accuracy (a human hair is about 75 microns),”
said Dave Cochrane, Team Leader of Optical Manufacturing at
KiwiStar Optics and the manager of the lens project.
“The final polishing process is done using powders as small as
1 micron, and an accuracy down to 0.05 microns (less than 1000
times smaller than a human hair).
“When both sides of the lens are polished, it is packed and
shipped to one of several specialist vacuum coaters in the USA for
anti-reflective coating. The lens is then returned to KiwiStar Optics
for final testing and inspection before being shipped to the client.”
According to KiwiStar Optics’ manager, Sandra Ramsay, “It’s
not widely known outside of astronomy circles that New Zealand
has this level of technical expertise and state-of-the-art equipment
to create these lenses”.
“KiwiStar Optics has a significant reputation globally for its
highly-specialised lenses and we are now working our way through
a substantial list of large contracts.”
Those contracts include three high-resolution cameras for the
VISTA telescope in Chile, as well as more lenses and spectrographs.
KIWISTAR OPTICS; CSIRO ■ JONATHAN NALLY
W KiwiStar Optics’ 1.1-metre-diameter lens will be used on a
spectrograph at the William Herschel Telescope in the Canary Islands.observation campaigns to be conducted
simultaneously.
“While some of us are timing a
pulsar, other astronomers could be
looking for the signs of newborn stars,”
Dr Hobbs said.
“The expertise built up in these
technologies will enable Australia to
compete effectively into the era of the
Square Kilometre Array, the world’s
largest radio telescope.”“Most of the projects the new
system will be used for are forefront
astronomical science,” added
Swinburne’s Professor Matthew Bailes,
leader of the university consortium.
Some of those projects include looking
for evidence of gravitational waves
from black holes in the infant Universe,
researching the interior of neutron stars
and mapping Galactic magnetic fields.
The university development
consortium is led by
Swinburne University
of Technology, with
funding from the
Australian Research
Council, Germany’s
Max Planck Institute
for Radioastronomy and
the Chinese Academy of
Sciences. Both CSIRO
and Swinburne designed
and built elements of the
receiver.
■ JONATHAN NALLYA new receiver, seen here in a testing
chamber, enables the CSIRO’s
Parkes radio telescope
to receive a wider
range of frequencies.