Happy New Year, all mapugers!

Pedro Santos asked:

>Valery,
>Can a SCT be refigured by a third party? I ask this because of the
>corrector plate.
>I thought that one the functions of the corrector plate is to correct
>errors of the main mirror,
>and that this corections are not equal within circuferences, making that
>the corrector cannot be rotated relative to the mirrors.


The function of the primary mirror in the SCT design is a correction of the
speherical aberration of primary+secodary system. If all elements of this
whole system was made with no astigmatism, corrector can be rotated with
no results to the image degradation.



>Does your refiguring is done taking the corrector plate into account ?
>Is the refiguring done in the main mirror only, or in the corrector plate
>or secondary mirror too ?

Yes, we have made figuring of the whole system, but the figuring was
applied to the primary mirror only. Initially our 10" F/10 scope suffered
from down turned edge and circular narrow vally between edge and center.
No astigmatism or local errors. This permit us to make refiguring. In the
case with asimmetric or local aberration, especially on corrector, we will be
not able to refigure whole system.




>Valery, you might be the right person to design a well corrected apocrom
>atic reducer/flattener for >10" SCT with the large thread (>5cm diameter).
>I know a lot of people would pay good money for such a reducer. The Lumicon
>has one but it is achromatic (only one lens I think).
>Please consider this request seriously.


We can also produce such a reducer-flattener. But for designing we need the
exact design of Meade's SCT. If anyone can help us to receive such EXACT
optical design, we will be hope to help many amateurs to have such apochromatic
corrector.

Now I can say that we have developed the color corrector for all Meade's
semi-APO refractors. Such corrector can be inserted into the objective end
of the star-diagonal and will correct the false colors to the level of
Astro-Physics
refractor. The corrector will not change the F/D and will correct small
field of 0.5 degree - enough for high-power visual and for CCD shooting.

If we will have enough inquires for such correctors, we will start
their serial manufacturing. Any comments, please. We also interested in
opinions of Meade's refractor owners. So, if anyone of you has friends with
Meade's refractors, ask them about theirs opinion. Such corrector can be
sell for around 800$ for the 6" and 7" , for 500$ for 5" and 430$ for the
4" scopes.


Best wishes in new 1998,


Valery Deryuzhin
ARIES INSTRUMENTS Co.

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