Australian Sky & Telescope - April 2018

82 AUSTRALIAN SKY & TELESCOPE April 2018

FOCAL POINT by Roger Davis

Where has my hobby gone?

From making mirrors and hypering film, to studying a computer screen in blissful comfort.

L

ooking back over my life as an

amateur astronomer, I’m amazed

at all the changes the years have

brought. In my early days, decades ago,

do-it-yourself was all the go... even before

DIY became a popular term. For instance,

there were none of today’s fancy CCD

cameras — we all used film, and we used

every trick in the book to extend exposure

times. One such method was hyper-

sensitising film, ie. baking it in a mixture

of hydrogen and nitrogen.

Some of the members of the

Astronomical Society of Victoria (ASV)

in Melbourne were using hypered film

and convinced me to do the same, but

first I had to learn all the techniques

and ‘build a tool to build a tool’. I didn’t

have the funds to import from Lumicon,

but luckily a benefactor gave me an

old Lumicon hypering kit. I ended up

making a new tank that could take four

film canisters. It helped that I had a

lathe with which to fabricate some parts.

I had to use the same hand-operated

vacuum pump on both the old and new

tanks, so I ended up with a strong grip!

The hardest thing to get right was the

hydrogen and nitrogen mix. And I think

my other half eventually got sick of

seeing film in the freezer.

I also tried making an optical plug

and helped a couple of friends with

their Cookbook cameras. Ah!... the

sound of a water cooling pump!

I made three different types of

graticule eyepieces

to guide with, and

experimented with

electronics to control

the brightness of

the LEDs. I needed

a smoother-running

telescope so I

machined the mount

to take steel roller

bearings and fitted a

better quality motor

drive, frequency

controlled. And I

made a better non-

flexing system to help

move my guidescope

to guide stars.

Of course, when

making mirrors I

needed to be able to

test them — I went

through so many modifications to,

and rebuilds of, my Foucault tester!

Then I mucked around with a simple

interferometer, building one from

instructions in the book Advanced

Telescope Making Techniques. Along the

way I acquired heaps of prisms and glass

cover slips!

I also needed a scope just for visual

observing, so I built a wooden mount in

about 1984. It was a Dobsonian, which

worked fine, but which then underwent

many alterations to become a better

scope. Then I had people asking me to

make big Dobs for them or alter theirs

to make them better. Then I made the

27-inch for the ASV, which was a stack

of fun.

I learned a lot! Fitting and turning,

electronics, electrics, optics, carpentry,

joinery, French polishing, routing etc.

That’s what filled in my time.

Now I have all the electronic gear.

I’m still learning how to use it — it’s a

steep curve as I am not totally computer

literate and still stumble over some

things. It has cost me heaps to obtain

commercially made equipment, a

computer, electronically controlled

mount, a super-duper SLR camera, a

relatively expensive CLS filter, books

on how to image, programs for image

processing and lots of headaches. And

I made a large power supply for 12V

cigarette-type plugs and 5V USB2,

But I am no longer outside pushing

a saw, hitting a nail or drilling a hole.

Nor am I scrounging through junkyards

looking for windscreen wiper motors

to drive my mounts, or brass and

aluminium to turn into parts.

My brain may be active, but my

bum is in a chair and I’m staring at

a computer screen while the Sun and

Moon are wheeling across the sky.

Where has my hobby gone? Inside,

where it’s warm!

W The author, pictured

in his early 30s with a

telescope he made when

in high school. Years

later he dusted it off and

got it going again, as

seen here.