Meade RCX400 is NOT Ritchey-Chretien.

"nick" wrote in message
ups.com...

It is possible to make a compact SCT corrected for spherical,
coma and astigmatism. For an f/8 system with f/2 primary, ~30%
minimum secondary and ~40% c.obstruction, it would require primary
conic of ~0.5 (oblate ellipsoid) and spherical or near-spherical
secondary. Corrector would be nearly twice stronger than in an
f/10, but the chromatism wouldn't change significantly, due to
lower secondary magnification.

But there is no basis whatsoever to call this design Ritchey-Chretien.
As Valery said, the RC has two hyperboloidal mirrors correcting for
spherical and coma. Any corrector that would significantly change this
configuration couldn't be called an RC. And two fast hyperbolical
mirrors with the rest of the package would definitely require higher
price, even for only decent optical quality. Still puzzled...

Vlad



What is the diference between the new meade scope compared to the vixen
VC200L?
It states an aspherical primary but I am not sure about the secondary. It
has a field flattener behind the mirror and no corrector plate.


Terry B
Moree
Australia

How can you possibly make a judgemet on a telescope that nobody but
Meade employees has seen? Making blanket statement about its performance
without an unbiased technical evaluation with actual hardware is nothing
better than Meade-bashing.

Matthew Ota
not a Meade employee

Vader wrote:
Nothing common between Meade RCX and true Ritchey-Chretien.
The only common is aplanatism - coma-free.

Calling these new scopes as Ritchey-Chretien is nothing, but
marketing hype to catch public attention. Peoples heard, that
Ritchey-Chretien are the best two mirror telescope systems.
But most of them don't know exactly what is what.

For CCD photography these new scopes will be not better, than
traditional SCT with focal reducer-comacorrector. Field is quite
enough, it is flat and coma-free.

New telescopes will have huge field curvature and will be
worser for visual observing - because of higher aspherics (less
smooth optics) and larger central obstruction.

If one will ask which scope I will use personally new RCX or
same size SCT, I will choose a SCT.


VD

Matthew Ota wrote:
How can you possibly make a judgemet on a telescope that nobody but
Meade employees has seen? Making blanket statement about its performance
without an unbiased technical evaluation with actual hardware is nothing
better than Meade-bashing.

Matthew Ota
not a Meade employee

I have to agree with the previous poster that whatever it is (and
regardless of how good it is), it is not a Ritchey-Chretien. But then
Meade has taken 5 (and is now taking 5 and 6) element eyepieces, and
declaired them to be Plossl's, so grossly bending the optical truth in
advertising is not a new thing for Meade. Meade's conception seems to
be that it's the name you call it that sells, so why not use the name
most likely to bring financial success.

Lawrence Sayre

--
My philosophy, in essence, is the concept of man as
a moral being, with his own happiness as the moral
purpose of his life, with productive achievement as
his noblest activity, and reason as his only absolute.

Ayn Rand (in the appendix to 'Atlas Shrugged')

You mean the Knights of the Shaky Table are succeeding in
Scamalot?



Lawrence Sayre wrote:

Matthew Ota wrote:
How can you possibly make a judgemet on a telescope that nobody but
Meade employees has seen? Making blanket statement about its performance
without an unbiased technical evaluation with actual hardware is nothing
better than Meade-bashing.

Matthew Ota
not a Meade employee

I have to agree with the previous poster that whatever it is (and
regardless of how good it is), it is not a Ritchey-Chretien. But then
Meade has taken 5 (and is now taking 5 and 6) element eyepieces, and
declaired them to be Plossl's, so grossly bending the optical truth in
advertising is not a new thing for Meade. Meade's conception seems to
be that it's the name you call it that sells, so why not use the name
most likely to bring financial success.

Lawrence Sayre

--
My philosophy, in essence, is the concept of man as
a moral being, with his own happiness as the moral
purpose of his life, with productive achievement as
his noblest activity, and reason as his only absolute.

Ayn Rand (in the appendix to 'Atlas Shrugged')

We can easily remember, that "Supermonocentric" eyepieces are not
monocentrics and of course, they are not supermonocentrics.

The same was with "ED-Star" name of objectives from the same
source, where no any trace of ED glasses, just flint with ubnormal
dispersion.

I think, that Meade decided to take their experience and apply it to
their re-optimized SCT.
These so called RCX scopes are nothing more, than optimized SCTs
(corrected for coma with little (excentricity) hyperboloid on
secondary
mirror).

VD

On 10 Jan 2005 09:09:12 -0800, "Vader"
wrote:

We can easily remember, that "Supermonocentric" eyepieces are not
monocentrics and of course, they are not supermonocentrics.


They appear to be closer to Hastings Triplets.

The same was with "ED-Star" name of objectives from the same
source, where no any trace of ED glasses, just flint with ubnormal
dispersion.


Now I know why the one I had wasn't spectacular.

I think, that Meade decided to take their experience and apply it to
their re-optimized SCT.
These so called RCX scopes are nothing more, than optimized SCTs
(corrected for coma with little (excentricity) hyperboloid on
secondary
mirror).

You've probably had the opportunity to actually find out
first-hand about the Supermonocentrics and the ED-Stars,
but you haven't yet seen the Meades or their true specs.
If they've optimized the SCTs in some way, it could be
a very good thing. Short of an achromatic corrector,
it could be the best thing to happen to SCTs since the
inception of the mass-produced scopes that Celestron
introduced long ago.
Years ago on this group, we discussed the idea of manufacturers
offering "higher quality" scopes for an increase in price.
Much like how you can buy a better diamond for more money.
This was rejected by most who thought it would stigmatize
the "lesser" product and leave a bad taste in the owner's
mouth. If this is Meade deciding to do it, I'm all for it.
The Russians have offered better quality Maks for some time,
for a price.
-Rich

RichA wrote:
On 10 Jan 2005 09:09:12 -0800, "Vader"
wrote:

We can easily remember, that "Supermonocentric" eyepieces are not
monocentrics and of course, they are not supermonocentrics.


They appear to be closer to Hastings Triplets.

The same was with "ED-Star" name of objectives from the same
source, where no any trace of ED glasses, just flint with ubnormal
dispersion.


Now I know why the one I had wasn't spectacular.

I think, that Meade decided to take their experience and apply it to
their re-optimized SCT.
These so called RCX scopes are nothing more, than optimized SCTs
(corrected for coma with little (excentricity) hyperboloid on
secondary
mirror).

You've probably had the opportunity to actually find out
first-hand about the Supermonocentrics and the ED-Stars,
but you haven't yet seen the Meades or their true specs.
If they've optimized the SCTs in some way, it could be
a very good thing. Short of an achromatic corrector,
it could be the best thing to happen to SCTs since the
inception of the mass-produced scopes that Celestron
introduced long ago.
Years ago on this group, we discussed the idea of manufacturers
offering "higher quality" scopes for an increase in price.
Much like how you can buy a better diamond for more money.
This was rejected by most who thought it would stigmatize
the "lesser" product and leave a bad taste in the owner's
mouth. If this is Meade deciding to do it, I'm all for it.
The Russians have offered better quality Maks for some time,
for a price.
-Rich


I think you will be hard pressed to tell a difference between a photo
taken with a RCX and an LX200. Meade is charging more for a more
complex optic set. this leads me to believe quality will be similar.
the RCX will have a wider field of view but it will still be limited.

I think, that Meade decided to take their experience and apply it to
their re-optimized SCT.
These so called RCX scopes are nothing more, than optimized SCTs
(corrected for coma with little (excentricity) hyperboloid on
secondary
mirror).


Hi Valery:

That's my suspicion too...and I think it would be a good thing. ;-)

Peace,
Rod Mollise
Author of _Choosing and Using a Schmidt Cassegrain Telescope_
Like SCTs and MCTs?
Check-out sct-user, the mailing list for CAT fanciers!
Goto http://members.aol.com/RMOLLISE/index.html

Now Matthew, don't go injecting common sense and reason into a
perfectly fun discussion.....

g