Ao Cassegrain 12.5" F16

[miki63au]

G'day all,:help:
I have a question. Do any one knows anything about this scope?
10-20 years ago AO made this 12.5" f16 classic cassegrain.
There are sum is on the market with heavy duty eq mount made in Australia.
The drive is AC motor.
Thanks,
Mick.

[Satchmo]

They were Dall -Kirkham design, with a spherical secondary. They were made up until the mid-70's. You would need to check it out optically.

Mark

[miki63au]

Tanks Mark,
do you know the design parameters,
and did you had any experiment with them?
Mick.

[UniPol]

I recall seeing these scopes in the early 1970's at Astro Optical in Crows Nest (then known as Amateur Astronomers Supply Co.) One of their catalogues from 1972 states the following :

12 1/2" CASSEGRAIN - E.F.L. 200"

We have recently developed this superb observatory instrument to meet the need of the advanced amateur both for visual and photographic work, This model represents the ultimate in this field. A Dall Kirkham configuration has been adapted to permit greater accuracy in manufacture. All mirrors are finally null tested on star images.

Special features include : Optics figured better than 1/15 wave accuracy: extensive baffling to reduce stray light; six high quality eyepieces ( 60, 40, 25, 18, 12.5 & 6mm). Useful magnification 80x - 800x; illuminated cross hair 8 x 50 finder; Unitron guidescope 77 x 60; aluminium tube with end band and dust cap; super rotary eyepiece selector; deluxe mount and stand; electric motor drive. Easy terms on $450 deposit - FULL PRICE $1350 Plus freight and packing.

The deluxe stand had 1 1/2" ground DEC and RA shafts supported by ball bearings.


Hope this helps.

Steve B

[Satchmo]

I've looked through a few. They had an F4 approx -0.7 conic constant primary and a 4X magnification secondary.

I actually worked at the AOS manufacturing facility from 1985 to 1988 but didn't see any any equipment suitable for final wavefront number ratings on Cassegrains in a null test ( not that thats needed but I always wondered where the advertised numbers came from ) . I would take each instrument on its merit if one comes up second hand and arrange a viewing under real skies.

[Satchmo]

Unipol, I remember well gazing at this instrument in the showroom as just a teenager in 1973. I simply couldn't imagine at the time a bigger telescope in amateur hands. What the Dobsonian revolution has done for the amateur astronomer has been phenomenal. $1350 would have been 1/3 of a years average wage in 1972. Now you could buy a portable 12" F5 Dob with 1.5 weeks wage :)

[miki63au]

Thanks every one,
what you know about the mount?
Is it has a "proper" worm gear drive or
only a spur gear?
I'll check the hole things, but I need as much
info as possible. Thanks a bunch!
Mick.