Page 4 ( Last level.)

The 0.61m f/15 Cassegrain Nasmyth ( 1996 - 1999 ).

Weight reduction is the main philosophy. The light secondary mirror is supported by six strong aluminum rods instead of the more common eight.
Telescope length: 2.3m and Weight approximately 60 kg
Weight of all : approximately 230 kg
The telescope is only a strong aluminum skeleton which hold the optics.
The telescope is also wrapped in aluminum foil for dust protection. I am at the eyepiece.



The telescope is enclosed in a conservatory with the roof glasses removed and replaced by a removable boat tarpaulin.

( Picture of Mr.Bean on the wall cheers me up after a nights observations with no results. )
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Aux.Telescope left : Russian 0.15m f/10 Maksutow.
Resolving power ( field test ) better than 0.7".
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The new place for the 15cm, now as guide ( MX516 & STAR 2000 ) and imaging telescope.

80mm finder in background



The R.A. drive system.



At last some optical informations.
Primary mirror: 0.05m x 0.61m f/4 precision annealed Pyrex ( instead of fine annealed ). It is resting on 18 points in the mirror cell. The secondary Cassegrain Mirror is 0.035m x 0.17m fine annealed Pyrex. It magnifies f/4 by 3.75 resulting in F/15 system.
Short diameter of Tertiary Mirror is 0.05m or 0.06m ( I have two ).
Reflectivity : 96 % both main mirrors.
( Tertiary 98 % 96 % ).
Production
( One and a half year ).

I got a nice agreement with two optical processing laboratories in U.S.A. to take their time to produce the f/4 F/15 system to within 1/10 wavelength. The secondary mirror was tested together with the primary during the polishing process.
( Producing the mirrors separately can have very expensive consequences.)




The observatory looks anonymous from the outside.
The dog is on guard.

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