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The "Halloran Telescope" |
| In November 2009,
member Joseph Halloran kindly donated a Pyrex 10-inch mirror
blank to the HB Astro Group. Dating back to 1965, this
beautiful piece of glass was in original box and with lap and
grinding materials and even an old handbook on mirror making
from the same period. Given the incredible low cost of
Newtonian telescopes these days, some may ask... why bother
making a mirror ? The answer is simple, it's a great piece of
glass with some history and if well figured will make a fine
telescope for the club and public viewing nights with a story
to tell. Since many are busy here and with our own lack of
experience in undertaking such a delicate optical creation,
Steve Massey kindly donated shipping costs of $55.00 to send
it down to friend Steve Quirk in Mudgee NSW who has made
several telescope mirrors in the past. Steve.Q has kindly
offered his time and skills to bring well deserved life to
this new club telescope. We have decided to go for f/6 and the
telescope will be eventually mounted on a typical
dobsonian style base.
A couple of the grits had the bags
breaking down in the satchels so they really needed attention.
So they all got washed and put into new containers. A test rig
for getting the focal length by reflecting the Sun and the
mirror has about an f/7 shape at the moment.
In the pictures below, work is already
underway in the basement of Quirk's Silo observatory. We will
post more pictures of its development as work progresses.
- SM |
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UPDATE JUNE 2010
It took 2 attempts to get the pitch correct. When casting the 1st
one, I left it cooling too long before pressing and could not get
a good contact across the mirror. After several heating and
pressing cycles with a lot of weight, I still could not get the
centre to contact, and worse, the mirror and tool locked together.
A lot of sweating and cussing finally separated them but destroyed
the pitch in doing so.
Second go, pressed the mirror quickly and made good contact...
whew!!! I faceted the pitch, pressed for a few hours and gave a 20
minute polish. A quick look on the test bench showed it was on
track. After another 30 minutes polishing, it showed just the
barest hint of haze but a very even polish right across the
surface. Another Ronchi test shows it to be nicely spherical. The
Foucault shadow shows the surface to be still a wee bit ''Dog
Biscuity'
but that will even out with more polishing. The figuring will then
be the final phase.
Cooking the pitch
1st Ronchi Test
50 minutes polishing
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UPDATE JULY 2010 |
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Beautiful home made mirror
cell now finished - well done Mr.Quirk!
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Home made ALT-AZ dobsonian
style base now done!
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Uncoated primary mirror seen
fitted in cell at rear of the tube.
Donated by Steve Massey, the secondary mirror and focuser are now fitted
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This image taken by Steve
Quirk with a point and shoot camera held up to the eyepiece of our
under-development club scope. Isn't it amazing what can be done
even without aluminised mirror coating!?!?
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UPDATE AUGUST 2010 |
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Telescope is now painted. The last step is
the mirror aluminising. One of the great things Steve Quirk has
done is to make the tube itself easily removed from the dobsonian
base so that it can in fact also be mounted in tube rings for use
on a heavy duty equatorial mount. Should make for a nice planetary
imaging scope as well. The club will off course foot the bill for
the mirror coating process. In the
final polishing stages, the image below was taken with the yet,
still un-aluminised glass. Quite amazing and shows the potential
resolving power of the scope.
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Steve Quirk's presentation to HBAS at the USQ
campus on the process of building the societies 10-inch telescope. |
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M42 Great Orion Nebula taken
in full Moon sky on the night of the telescopes handover
presentation at USQ
Camera GSTAR-EX (no filters) 3 separate exposures - Credit Steve
Quirk |
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Jupiter and the Great Red
Spot on the night of the telescopes handover presentation at USQ
Camera ProStar colour CCD imager - Credit Steve Massey |
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8 months in the making, the societies
wonderful 10-inch telescope is presented by Steve Quirk seen right
with Society treasurer Robert Jocumsen (left) At left: members gather to
take a peek while channel 7 local news interviews society members.
Society president Trevor Taylor can be seen inspecting the new
telescope in the background. |
Above: The Societies first formal presentation
award which was presented to Steve Quirk for his outstanding
contribution to the Hervey Bay Astronomical Society. This lovely
piece was hand crafted by society member Andy Walters.
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Steve Quirk (left) with Joseph Halloran
(centre) and Guilio Sartore (right background) with clubs 10-inch custom
made telescope.
Our sincere thanks to Mr. Steve Quirk for his
effort and provision of the tube and mount. To Joseph Halloran for
the pyrex glass and compounds and to Steve Massey
for the direction, supply of component parts and shipping costs to
make this telescope come to life. It is truly a lovely telescope.
|
 VIDEO
from CH7 Local News
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