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[ATM] 16" RCC primary
Hello Guys,
Well, well the reverse methode to make first the sec and
than the primary was not in my mind. It is interesting.
The Ross-null, I tried it before to make parabs but I founded
messy,maybe because I didn't know the exact dadas of my
Ross-null lens. I downloaded the Figure Xp and I think I
will try the next methode. I can calculate the LA for the
primary if it would be a paraboloid, and I can calculate the
RA for the prim. if it would be the desired hiperboloid.
I can nullifing the paraboloidal LA amount in
autocollimation against my big flat. Make a Couder Mask and
just measure the remained LA wich should be, if I
am at the desired curve. Now I just have to figure out how
should I set up the Figure Xp wich calculates me the exact
readings for a masked autocollimated mirror.
If I put the couder screen on my autocollimated parabola,
than there is no measurable difference between the readings.
But if I push the figuring forward I will put measurable
diff. between the screen windows.
Maybe this is not the best methode, but I don't need extra
mirrors and lenses for testing. Finally I put the scope
toghether and figure the senondary to macth with the primary
and null them, against my flat.
Anyway here are the dates of the design:
Rprim: 3200mm
Rsec: -1870mm
t: 1054mm
BFL: 1304mm
Feff: 9,5
Im diam: 18.56mm is 0.28 degres
CCp: -1.18
CCsec: -8.53
Primary diam: 400mm
Secondary diam: 140mm
I think.
The main reason why the primary is f/4, because I have made
Newtonian mirrors in this diam before and I know how
difficult to make an excellent paraboloid at this f number
and this diameter, even in autocollimation. That's why I didn't want to make an F/3
hyperboloid surface.
Clear Skies!
--
Best regards,
Attila Schné
mailto:yolo@chello.hu
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