80mm ED Orions suffering from pinched optics?

On a couple of occassions I've seen pinched optics
in this scope. The diffraction rings are deformed
and the diffraction disc is triagular. This happens
when the temp. drops to around freezing or lower.
One person also noticed this on the ED apo yahoo
group. IMO, it's probably due to the aluminum cell
diameter being too close to the diameter of the
lens elements, and when it contracts due to the cold
the elements are pressured. While this doesn't effect
the image quality of planets, etc, very much (mild
astigmatism usually doesn't) it is a bit of a problem
with double stars. I figure I'll contact Orion to see
if any other cases of this have cropped up and if they've
determined it's due to the cell or something else.
It could be internal strain the glass, but I doubt it.
Owners of Orion, Celestron or Skywatcher versions of
this scope should look for it when the temp. drops.

That's why the big price drop now on this scope. ($399)
They suck lot of people into to buy this thing.

JS

"RichA" wrote in message
...
On a couple of occassions I've seen pinched optics
in this scope. The diffraction rings are deformed
and the diffraction disc is triagular. This happens
when the temp. drops to around freezing or lower.
One person also noticed this on the ED apo yahoo
group. IMO, it's probably due to the aluminum cell
diameter being too close to the diameter of the
lens elements, and when it contracts due to the cold
the elements are pressured. While this doesn't effect
the image quality of planets, etc, very much (mild
astigmatism usually doesn't) it is a bit of a problem
with double stars. I figure I'll contact Orion to see
if any other cases of this have cropped up and if they've
determined it's due to the cell or something else.
It could be internal strain the glass, but I doubt it.
Owners of Orion, Celestron or Skywatcher versions of
this scope should look for it when the temp. drops.

I figure I'll contact Orion to see
if any other cases of this have cropped up and if they've
determined it's due to the cell or something else.
It could be internal strain the glass, but I doubt it.
Owners of Orion, Celestron or Skywatcher versions of
this scope should look for it when the temp. drops.

Do they support the retaining ring design? How are the elements held in
place?
This concept does not bode well in a Northern US and Canadian winter.

Sounds like you're familiar with the term chicken choker... Probably VERY
familiar... I guess that happens sometimes, up north...

--
Jan Owen

To reach me directly, remove the Z, if one appears in my e-mail address...
Latitude: 33.662
Longitude: -112.3272

"moT" wrote in message
newsjwmd.105438$VA5.23650@clgrps13...

I figure I'll contact Orion to see
if any other cases of this have cropped up and if they've
determined it's due to the cell or something else.
It could be internal strain the glass, but I doubt it.
Owners of Orion, Celestron or Skywatcher versions of
this scope should look for it when the temp. drops.

Do they support the retaining ring design? How are the elements held in
place?
This concept does not bode well in a Northern US and Canadian winter.

On Tue, 16 Nov 2004 23:46:28 GMT, "moT" wrote:


I figure I'll contact Orion to see
if any other cases of this have cropped up and if they've
determined it's due to the cell or something else.
It could be internal strain the glass, but I doubt it.
Owners of Orion, Celestron or Skywatcher versions of
this scope should look for it when the temp. drops.

Do they support the retaining ring design? How are the elements held in
place?
This concept does not bode well in a Northern US and Canadian winter.


There is a retaining ring, but I figured the pinch came from the
inside diameter of the cell as it relates to the diameter of the lens
elements. If this is the cause, then it's easy to fix.
If it's due to a lack of homogeneity(sp?) of the lens material, then
it's insurmountable. But I really doubt that is likely.
-Rich

On Tue, 16 Nov 2004 23:37:16 GMT, "Szaki" wrote:

That's why the big price drop now on this scope. ($399)
They suck lot of people into to buy this thing.

JS

People should bear in mind that this kind of thing
is hardly detrimental to the images produced by the
scope. If it were severe spherical aberration, then
we'd really have a problem.
-Rich

"Jan Owen" wrote in message
news:EZwmd.122991$cJ3.118548@fed1read06...
Sounds like you're familiar with the term chicken choker... Probably VERY
familiar... I guess that happens sometimes, up north...

--
Jan Owen


Not at all, enlighten me.

If this is the cause, then it's easy to fix.
If it's due to a lack of homogeneity(sp?) of the lens material, then
it's insurmountable. But I really doubt that is likely.
-Rich

If the problem is with the glass, then it ought to show up regardless of the
temperature...

Jon