Bringing back to life a Salmoiraghi
5” of 1920s
This
is the little story of an unexpected project.
Just
before Easter 2008, I was badly after a 160 Unitron being advertised on eBay… when,
all of a sudden, my attention was taken elsewhere...
In
those very days, discussing with a Gentleman about classic and ancient
telescopes, he handled me a couple of papers… showing a brand almost forgotten
(at least in the Astronomical domain).
A
jump into the past. Wonderful instruments. Very rare indeed.
Apparently
no more than a handful of these telescopes of various diameters still exist,
obviously well kept in Observatory Museums.
Oh,
well, I ask if I can have a copy of the papers for my archive.
At
this moment the Gentleman - almost hesitating - asks me whether I am really
interested… and I would be keen… “You know - he says - something so old can be
in such bad conditions”… I am not quite sure what we are talking about…
He
takes me into a stockroom, where I find a tall super heavy old pier in black
cast iron and two big wooden boxes in quite a bad shape. I mean BAD. Inside, to
my great surprise, are stored the components of a 125mm Equatorial Refractor (N.12 in the Catalogue page hereunder).
Oh my…!
The instrument is coming from an old dismantled observatory.
It’s a 1920s vintage.
It went rusty in most parts. And this… “will be yours, if you
feel like restoring it”…! Of
course I was quoted a price but, honestly, it was a nominal one.
My ears are buzzing: I neved did something so complicated.
But I cannot possibly imagine living these boxes forgotten. I feel this as a
honor, a true service to History of Astronomy.
I cannot possibly say no. I shall learn.
So, yes, of course, yes: I take it.
Well, not like that, of course: I had to hire a truck so as
to move the cast iron pedestal, and all the rest…!
Getting back home, I devote an area of my flat to the
instrument and started a cereful analysis.
The
tube is Walnut. Conical shape. Bad conditions.
State
of the tube end.
Scratches
on the tube.
Interior of the tube, showing a series of metal reinfocement
rings.
Mmm, here I need a professional Refurbisher. Luckily I’ve got
a good one.
As
per the metal parts, they’re mostly rusty and jammed. Here I’ll do it myself.
Focuser
and Finder block
Everything
is painted. But paint is basically gone.
These
images of the Weight-Driven Right-Ascension Mechanism with Speed Regulator on
top can provide an idea of the general state.
Mechanism
was rusty and jammed as well.
Under
the paint, much to my surprise I realize that everything is brass.
Handmade,
solid brass. So, I tell myself I shall go for bare brass.
*
Luckily,
the Objective shows no scratches. Just plenty of fungi.
So,
let’s do it.
*
While
the Walnut tube is with the restaurateur, I start for days and days (weeks…
months…) to carefully dismantle every single piece, getting rid of the paint,
the dirt, the rust, etc.
Little
by little, my working table shows the advancements…
When
all the components of the OTA are ready, I move to the Weight-Driven mechanism.
A
nightmare. A true nightmare.
The
easiest was the Speed Regulator
A
Work-of-Art in itself: everything is hand made, down to the spring.
The
glass is blown (with small bubbles inside).
Then
a loooong work started to open up and clean all the mechanism with acid…
It
was impossible to recover the wire, which was severely damaged in two points… gotta
find a replacement.
*
When
the Walnut tube came back from the Restaurateur, I was finally able to put all
the pieces together.
Not
an easy task indeed, as everything is hand made and each screw wants its own hole.
For
three times I failed.
The
fourth attempt was the good one.
Now,
after almost 90 years, the telescope is back to life !
This
is a detail of the focuser side, with the finder.
Side
view of the focuser and finder
The
whole OTA resting on the bed.
Being
170cm long, it is difficult to picture it anywhere else, till I am not finished
with the mount…
After
quite a bit of Wonderfluid and Wondercloth, the lens back to life as well…
And
now it’s the time of the weight-driven mechanism…
Finally
all the pieces are ready.
Time
to put things back together…
We’re
almost there…
At
last... !!!
One
last piece and… 90 years later… welcome back to life…!
As
I said, I still have to find a replacement for the steel wire, but that is not
worrying me too much.
Btw,
any hint from any reader on where to find a suitable wire would be much
appreciated.
*
Now
it’s time to work on the mount itself.
It
will still take a while.
But
we’re surely getting there…;-)
*
In
the meantime, here are a few goodies:
An
Helioscope in its box.
Perfectly
preserved.
It
came with the Telescope.
And,
last but not least, the original Eyepieces box with planetary filters (not
shown: there is a hidden compartment)
Just
minor cleaning needed.
Using
the filters it came out that the lens is heavily optimized for Mars
observation.
On
the blue side of the spectrum the spherical is nothing extraordinary.
On
the other side, with a red filter in place, images are extremely sharp.
It
was obviously built in Lowell and Schiaparelli era.
*
Well,
as already said, I am not finished with the restoration yet. But, when I saw
the OTA and weight-driven mechanism back to life, I thought it was time to
start sharing the story.
Hope
you enjoyed reading it !
Thanks
Max
PS:
Obviously, that eBay auction went totally off my mind… so someone else is now happily
looking after the 160 Unitron…!