Maybe it's time for a luxury SCT?

"Deserve's got nothin' to do with it."

-- Wm. Munny, from "The Unforgiven", 1992

wrote:

Don't we all deserve a little better quality of life?
Rather than a cheaper widgit?

Chris.B

We had the opportunity to buy luxury SCTs a couple of years ago. Except
it had Maksutov optics from Astro Physics, and cost $10,000.

You see, here is the rub: The difference between a telescope designed
and made to a cost structure, a true high end optic (n.e. Luxury optic)
is not just a bunch of added bagage or a slightly better mount. It
starts with a dedication to getting the optics right; a real 1/10 wave
smooth wavefront in an optical tube assembly that is done to the same
levels of precision as the optics.

Now, once you get the OTA up to luxury levels, you end up having to put
it on a mount of similar capabilities. These start in the $5000 range
and go up from there.

At this point, you see that making a luxury SCT is much like changing a
Ford or Chevy into a Ferrari or Rolls Royce. That is there is not much
to compare between the mass market range and the true luxury end. And
that is probably why it is not done.

Mitch

Well said. There is something in the American psyche, especially for men
in their '20s, that makes them believe adding accessories is the
equivalent of purchasing a properly designed product.

The original premise was that a standard SCT could be "fixed" by
upgrading a few components and adding bells and whistles (something
Meade and Celestron have been doing regularly). But as you point out,
the real solution is to abandon the SCT design baggage and start from
scratch -- as in the AP MCT.

wrote:

We had the opportunity to buy luxury SCTs a couple of years ago. Except
it had Maksutov optics from Astro Physics, and cost $10,000.

You see, here is the rub: The difference between a telescope designed
and made to a cost structure, a true high end optic (n.e. Luxury optic)
is not just a bunch of added bagage or a slightly better mount. It
starts with a dedication to getting the optics right; a real 1/10 wave
smooth wavefront in an optical tube assembly that is done to the same
levels of precision as the optics.

Now, once you get the OTA up to luxury levels, you end up having to put
it on a mount of similar capabilities. These start in the $5000 range
and go up from there.

At this point, you see that making a luxury SCT is much like changing a
Ford or Chevy into a Ferrari or Rolls Royce. That is there is not much
to compare between the mass market range and the true luxury end. And
that is probably why it is not done.

Mitch

On Mon, 14 Feb 2005 10:50:52 -0700, Tim Killian
wrote:

Well said. There is something in the American psyche, especially for men
in their '20s, that makes them believe adding accessories is the
equivalent of purchasing a properly designed product.

The original premise was that a standard SCT could be "fixed" by
upgrading a few components and adding bells and whistles (something
Meade and Celestron have been doing regularly). But as you point out,
the real solution is to abandon the SCT design baggage and start from
scratch -- as in the AP MCT.

I guess it depends on how "luxury" is designed. In the case of
commercial SCTs, the design _can_ be fixed with only a few upgrades, and
no radical redesign is necessary. The optics are already near perfect,
so there is little need for change there except possibly for better
baffling. Mechanically, the main thing the OTA requires is a better
system for moving the primary mirror. Mechanically, the main thing the
mount requires is somewhat larger, higher quality worm gears. These
simple changes would allow a commercial SCT (M or C) to perform
similarly to the AP scope you describe on a G-11 mount, for a fraction
of the cost.

_________________________________________________

Chris L Peterson
Cloudbait Observatory
http://www.cloudbait.com

Dream on, it's not against the law. Steely Dan's "Time out of Mind" is
playing and the lyric /The water will change to cherry wine/ (heroin can
do that) seems appropriate to this discussion. In the real world
however, compromised designs tend to remain compromised.

Chris L Peterson wrote:

On Mon, 14 Feb 2005 10:50:52 -0700, Tim Killian
wrote:


Well said. There is something in the American psyche, especially for men
in their '20s, that makes them believe adding accessories is the
equivalent of purchasing a properly designed product.

The original premise was that a standard SCT could be "fixed" by
upgrading a few components and adding bells and whistles (something
Meade and Celestron have been doing regularly). But as you point out,
the real solution is to abandon the SCT design baggage and start from
scratch -- as in the AP MCT.


I guess it depends on how "luxury" is designed. In the case of
commercial SCTs, the design _can_ be fixed with only a few upgrades, and
no radical redesign is necessary. The optics are already near perfect,
so there is little need for change there except possibly for better
baffling. Mechanically, the main thing the OTA requires is a better
system for moving the primary mirror. Mechanically, the main thing the
mount requires is somewhat larger, higher quality worm gears. These
simple changes would allow a commercial SCT (M or C) to perform
similarly to the AP scope you describe on a G-11 mount, for a fraction
of the cost.

_________________________________________________

Chris L Peterson
Cloudbait Observatory
http://www.cloudbait.com

On Mon, 14 Feb 2005 11:15:25 -0700, Tim Killian
wrote:

Dream on, it's not against the law. Steely Dan's "Time out of Mind" is
playing and the lyric /The water will change to cherry wine/ (heroin can
do that) seems appropriate to this discussion. In the real world
however, compromised designs tend to remain compromised.

True enough.

_________________________________________________

Chris L Peterson
Cloudbait Observatory
http://www.cloudbait.com

On Mon, 14 Feb 2005 10:50:52 -0700, Tim Killian
wrote:

Well said. There is something in the American psyche, especially for men
in their '20s, that makes them believe adding accessories is the
equivalent of purchasing a properly designed product.

The original premise was that a standard SCT could be "fixed" by
upgrading a few components and adding bells and whistles (something
Meade and Celestron have been doing regularly). But as you point out,
the real solution is to abandon the SCT design baggage and start from
scratch -- as in the AP MCT.

Sigh. You already read the OGS RC owner say there was very little
difference between his scope used on a planet and the Celestron SCT.
Do you SCT-slammers only parrot what each other says, or do you
actually try to use one of the scopes, before making your statements?
I can't believe the latter, because you are basically wrong in your
assertions.
-Rich

ogs quoted me a strehl of better than .92. from what I hear most of
them are considerably higher (Gendler) I've even seen tests at over
..99. regardless, a poor OGS will perform as well as a respectable sct.
my main concern is with the two extra surfaces the schmid plate
introduces. all things being equal the sct will have less contrast than
a classical cass.


Fiona

How does any OTA with a 35% central obstruction achieve a Strehl of .99?

wrote:

ogs quoted me a strehl of better than .92. from what I hear most of
them are considerably higher (Gendler) I've even seen tests at over
.99. regardless, a poor OGS will perform as well as a respectable sct.
my main concern is with the two extra surfaces the schmid plate
introduces. all things being equal the sct will have less contrast than
a classical cass.


Fiona

perhaps it would be better to say RMS of 0.017
(http://voltaire.csun.edu/roland/interfer.html)