Trapezium and SCT's

Last night I attended a star party here in Central Texas. The seeing was
unusually good for this area, and, among other things, I observed the
Trapezium through three SCT's -- an old orange-tube C8, a brand new one-arm
C8, and a recent-vintage Meade 10". Through the orange tube, the Trapezium
stars were beautiful, sharp points and the E and F stars easy to see.
Through the other two scopes, the Trapezium stars appeared a bit "dull" and
lackluster, and the E and F stars were barely perceptible.

Was the orange tube just an unusually good SCT, or maybe it was just better
collimated? The eyepieces and diagonals were comparable on the two C8's,
and the Meade had high-dollar TeleVue eyepieces and diagonal.

I tell you, after observing through the orange tube, I am convinced that
SCT's can give excellent views.

--
To reply, remove the "z" if one appears in my address
"Rank Amateur" wrote in message
link.net...
Last night I attended a star party here in Central Texas. The seeing
was
unusually good for this area, and, among other things, I observed the
Trapezium through three SCT's -- an old orange-tube C8, a brand new
one-arm
C8, and a recent-vintage Meade 10". Through the orange tube, the
Trapezium
stars were beautiful, sharp points and the E and F stars easy to see.
Through the other two scopes, the Trapezium stars appeared a bit "dull"
and
lackluster, and the E and F stars were barely perceptible.

Was the orange tube just an unusually good SCT, or maybe it was just
better
collimated? The eyepieces and diagonals were comparable on the two
C8's,
and the Meade had high-dollar TeleVue eyepieces and diagonal.

I tell you, after observing through the orange tube, I am convinced that
SCT's can give excellent views.

Any of those scopes should have shown the Trapezium with all six stars
crisp and well defined, given the kind of seeing you describe, and the
fact you saw them that way in one of the scopes. The other scopes may not
have been properly collimated, may not have been in thermal equilibrium
with the surrounding air, or both. But they should all have shown all six
stars sharply if one did. And the 10" easiest of all... Could be a bad
scope, but chances are, it was collimation and/or equilibration...

Here's a nice map:
http://www.laughton.com/paul/rfo/trap/trap.html

Excellent seeing here in South Jersey tonight in spite of the moon.

Forgot to mention that I saw a meteor go past M42 about an hour ago while
observing...

"Rank Amateur" wrote in message
link.net...
Last night I attended a star party here in Central Texas. The seeing was
unusually good for this area, and, among other things, I observed the
Trapezium through three SCT's -- an old orange-tube C8, a brand new
one-arm
C8, and a recent-vintage Meade 10". Through the orange tube, the
Trapezium
stars were beautiful, sharp points and the E and F stars easy to see.
Through the other two scopes, the Trapezium stars appeared a bit "dull"
and
lackluster, and the E and F stars were barely perceptible.

Was the orange tube just an unusually good SCT, or maybe it was just
better
collimated? The eyepieces and diagonals were comparable on the two C8's,
and the Meade had high-dollar TeleVue eyepieces and diagonal.

I tell you, after observing through the orange tube, I am convinced that
SCT's can give excellent views.


My guess is that the orange tube was in proper collimation and performing
normally, while the other two were out of collimation. I find it amazing
that too many SCT owners don't know the first thing about collimation. Go
to any star party and you will find many SCTs which are out of proper
collimation. At this moment, I own 3 SCTs and I check collimation before
each use.

While the SCT design pays some in optical performance for it's outstanding
portability, it will still provide excellent views. What the SCT loses in
optical performance, it will more than make up in easy to carry, easy to set
up, easy to transport and easy to buy aperture.

Al

And, I'll have you know boys and girls, that that orange tube that he
looked through belonged to ME!!!!! No Kiddin'!

HA!

The SCT in question is a vintage celestron pacific, produced in about
1974. The diagonal was the original stock issued with the scope - prism
style. The eyepiece was a newer celestron plossl.

As I type this I am proud enough to bust!

Chris

Rank Amateur wrote:

Last night I attended a star party here in Central Texas. The seeing was
unusually good for this area, and, among other things, I observed the
Trapezium through three SCT's -- an old orange-tube C8, a brand new one-arm
C8, and a recent-vintage Meade 10". Through the orange tube, the Trapezium
stars were beautiful, sharp points and the E and F stars easy to see.
Through the other two scopes, the Trapezium stars appeared a bit "dull" and
lackluster, and the E and F stars were barely perceptible.

Was the orange tube just an unusually good SCT, or maybe it was just better
collimated? The eyepieces and diagonals were comparable on the two C8's,
and the Meade had high-dollar TeleVue eyepieces and diagonal.

I tell you, after observing through the orange tube, I am convinced that
SCT's can give excellent views.

Al wrote:

"Rank Amateur" wrote in message
link.net...

Last night I attended a star party here in Central Texas. The seeing was
unusually good for this area, and, among other things, I observed the
Trapezium through three SCT's -- an old orange-tube C8, a brand new

one-arm

C8, and a recent-vintage Meade 10". Through the orange tube, the

Trapezium

stars were beautiful, sharp points and the E and F stars easy to see.
Through the other two scopes, the Trapezium stars appeared a bit "dull"

and

lackluster, and the E and F stars were barely perceptible.

Was the orange tube just an unusually good SCT, or maybe it was just

better

collimated? The eyepieces and diagonals were comparable on the two C8's,
and the Meade had high-dollar TeleVue eyepieces and diagonal.

I tell you, after observing through the orange tube, I am convinced that
SCT's can give excellent views.



My guess is that the orange tube was in proper collimation and performing
normally, while the other two were out of collimation. I find it amazing
that too many SCT owners don't know the first thing about collimation. Go
to any star party and you will find many SCTs which are out of proper
collimation. At this moment, I own 3 SCTs and I check collimation before
each use.

While the SCT design pays some in optical performance for it's outstanding
portability, it will still provide excellent views. What the SCT loses in
optical performance, it will more than make up in easy to carry, easy to set
up, easy to transport and easy to buy aperture.

Al



Yeah, the collimation on mine is pretty good, but the fellow with the
meade also says he spends a lot of time lining things up. He had a
binoviewer on his, which may take a little getting used to. Still I've
gotta say that I did get lucky with the glass on my orange tube. It's
one of the good ones -

Chris
Still proud enough to bust.

Yup, Chris, you are da man with da scope! Hehe. Now, I don't want to say
that the other two SCT's were bad, because they weren't. But, the view
through yours was definitely the best of the three.

Bill


"starburst" wrote in message
.. .
And, I'll have you know boys and girls, that that orange tube that he
looked through belonged to ME!!!!! No Kiddin'!

HA!

The SCT in question is a vintage celestron pacific, produced in about
1974. The diagonal was the original stock issued with the scope - prism
style. The eyepiece was a newer celestron plossl.

As I type this I am proud enough to bust!

Chris

Rank Amateur wrote:

Last night I attended a star party here in Central Texas. The seeing
was
unusually good for this area, and, among other things, I observed the
Trapezium through three SCT's -- an old orange-tube C8, a brand new
one-arm
C8, and a recent-vintage Meade 10". Through the orange tube, the
Trapezium
stars were beautiful, sharp points and the E and F stars easy to see.
Through the other two scopes, the Trapezium stars appeared a bit "dull"
and
lackluster, and the E and F stars were barely perceptible.

Was the orange tube just an unusually good SCT, or maybe it was just
better
collimated? The eyepieces and diagonals were comparable on the two
C8's,
and the Meade had high-dollar TeleVue eyepieces and diagonal.

I tell you, after observing through the orange tube, I am convinced that
SCT's can give excellent views.

The SCT in question is a vintage celestron pacific, produced in about
1974

The majority of the older orange-tube Celestron's I've used have been excellent
performers, while FEW of the black-tubes from the 80's I've used have proven to
be more than merely acceptable.
Current production scopes seem to vary greatly.
Aside from these 'general' impressions, the comment that many SCT owner's don't
seem to have any idea how important it is to have proper collimation is TOO
TRUE!
Many marginal performers have delivered acceptable images after a bit of
tweaking.
At the recent Winter Star Party I was invited to take a look at Jupiter through
a C-11 (it's owner was very excited about how 'terrific' the view was).
Suffice to say that in was, in reality, a terrible image.
Only the N and S eq belts were visible (no detail was seen in either) and the
overall view was what you might expect if you were looking through a gauze
curtain!
At the same time, 'lesser' scopes (like an Orion XT-6) nearby were generating
really nice detail...crisp and contrasty.
I thanked him for the look and innocently asked if he ever checked his scope's
collimation. He assured me that "SCT's don't need to be collimated. That's one
of the advantages of the design over Newtonians".
- sigh -


Mike Harvey

Rod should be posting here - but many have experienced a variety of C8's
over the years, some good, some not. Of the orange tubes the older and those
in the period 74-78/9 seemed the best, while those in the 80's I would look
well
about (optically) before buying. Many say the recent C8's are good but I can
only
say I stopped buying C8's a long time ago and of those I routinely collimate
for
people very summer I have yet tosee a bad recent C8/11/12 and I really like the

9.25's. But owning a sct and not knowing how to collimate is a real shame.

anyone ever see a self-collimating sct?

Jerry




Rank Amateur wrote:

Last night I attended a star party here in Central Texas. The seeing was
unusually good for this area, and, among other things, I observed the
Trapezium through three SCT's -- an old orange-tube C8, a brand new one-arm
C8, and a recent-vintage Meade 10". Through the orange tube, the Trapezium
stars were beautiful, sharp points and the E and F stars easy to see.
Through the other two scopes, the Trapezium stars appeared a bit "dull" and
lackluster, and the E and F stars were barely perceptible.

Was the orange tube just an unusually good SCT, or maybe it was just better
collimated? The eyepieces and diagonals were comparable on the two C8's,
and the Meade had high-dollar TeleVue eyepieces and diagonal.

I tell you, after observing through the orange tube, I am convinced that
SCT's can give excellent views.