secondary mirror

Can you get a new secondary mirror for a C8 thats at least 10 years old?

On Jan 6, 5:26*pm, "Mickman" wrote:
Can you get a new secondary mirror for a C8 thats at least 10 years old?

You might find a secondary surplus, but it is unlikely it will work
well. Celestron applies figuring to its secondary mirrors to bring the
optical systme fully within spec.

On Jan 7, 9:02*am, RMOLLISE wrote:
On Jan 6, 5:26*pm, "Mickman" wrote:

Can you get a new secondary mirror for a C8 thats at least 10 years old?

You might find a secondary surplus, but it is unlikely it will work
well. Celestron applies figuring to its secondary mirrors to bring the
optical systme fully within spec.

What figuring? Surely the mirror just needs to be flat and mounted as
stress free as possible.

On Jan 7, 6:26*am, Helpful person wrote:
On Jan 7, 9:02*am, RMOLLISE wrote:

On Jan 6, 5:26*pm, "Mickman" wrote:

Can you get a new secondary mirror for a C8 thats at least 10 years old?

You might find a secondary surplus, but it is unlikely it will work
well. Celestron applies figuring to its secondary mirrors to bring the
optical systme fully within spec.

What figuring? *Surely the mirror just needs to be flat and mounted as
stress free as possible.

Hi
The secondary on C8 isn't flat. It is a hyperbolic convex
mirror surface.

For the original poster:
What is the problem with the mirror you have. Mirrors
can be recoated. Of course if it is broken, that is a different
story.
Dwight

On Wed, 7 Jan 2009 06:26:04 -0800 (PST), Helpful person
wrote:

What figuring? Surely the mirror just needs to be flat and mounted as
stress free as possible.

The secondary of an SCT is not a flat mirror!
_________________________________________________

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

It appears recoating is the only recourse. This secondary convex mirror
coating is damaged with
what appears to be mold that has embedded into it. It doesn't wipe clean. It
stays. It SUX !







wrote in message
...
On Jan 7, 6:26 am, Helpful person wrote:
On Jan 7, 9:02 am, RMOLLISE wrote:

On Jan 6, 5:26 pm, "Mickman" wrote:

Can you get a new secondary mirror for a C8 thats at least 10 years
old?

You might find a secondary surplus, but it is unlikely it will work
well. Celestron applies figuring to its secondary mirrors to bring the
optical systme fully within spec.

What figuring? Surely the mirror just needs to be flat and mounted as
stress free as possible.

Hi
The secondary on C8 isn't flat. It is a hyperbolic convex
mirror surface.

For the original poster:
What is the problem with the mirror you have. Mirrors
can be recoated. Of course if it is broken, that is a different
story.
Dwight

It appears recoating is the only recourse. This secondary convex mirror
coating is damaged with
what appears to be mold that has embedded into it. It doesn't wipe clean.
It stays. It SUX !

If you remove the secondary, which will require removing the corrector, keep
in mind that all of these are mounted in a specific rotation relative to the
primary. There may be alignment marks on the corrector's cell and, maybe,
the secondary's mount, too. The rotation is unique to each scope, adjusted
at the time of original assembly. To get good images on reassembly, you'll
need to respect the correct rotation of the corrector and secondary.
--
Curtis Croulet
Temecula, California
33°27'59"N, 117°05'53"W

Mickman wrote:

It appears recoating is the only recourse. This secondary convex mirror
coating is damaged with
what appears to be mold that has embedded into it. It doesn't wipe clean. It
stays. It SUX !


if you remove the corrector and secondary put alignment
marks (felt tip pend) on everything so you can reassemble everything just as it
was removed. This is a must. It
preserves the original orientation of the optics - just
as Curtis says...

J.


wrote in message
...
On Jan 7, 6:26 am, Helpful person wrote:
On Jan 7, 9:02 am, RMOLLISE wrote:

On Jan 6, 5:26 pm, "Mickman" wrote:

Can you get a new secondary mirror for a C8 thats at least 10 years
old?

You might find a secondary surplus, but it is unlikely it will work
well. Celestron applies figuring to its secondary mirrors to bring the
optical systme fully within spec.

What figuring? Surely the mirror just needs to be flat and mounted as
stress free as possible.

Hi
The secondary on C8 isn't flat. It is a hyperbolic convex
mirror surface.

For the original poster:
What is the problem with the mirror you have. Mirrors
can be recoated. Of course if it is broken, that is a different
story.
Dwight

On Jan 7, 8:35*pm, jerry warner wrote:
Mickman wrote:
It appears recoating is the only recourse. *This secondary convex mirror
coating is damaged with
what appears to be mold that has embedded into it. It doesn't wipe clean. It
stays. It SUX !

if you remove the corrector and secondary put alignment
marks (felt tip pend) on everything so you can reassemble everything just as it
was removed. This is a must. It
preserves the original orientation of the optics - just
as Curtis says...

J.

---snip---

Hi
Don't depend on a felt marker. These will not survive coating.
If you have a demel with a small diamond bit, make a small
mark on the edge or back side of the corrector and mirror.
Dwight

wrote in message
...
On Jan 7, 8:35 pm, jerry warner wrote:
Mickman wrote:
It appears recoating is the only recourse. This secondary convex mirror
coating is damaged with
what appears to be mold that has embedded into it. It doesn't wipe
clean. It
stays. It SUX !

if you remove the corrector and secondary put alignment
marks (felt tip pend) on everything so you can reassemble everything just
as it
was removed. This is a must. It
preserves the original orientation of the optics - just
as Curtis says...

J.

---snip---

Hi
Don't depend on a felt marker. These will not survive coating.
If you have a demel with a small diamond bit, make a small
mark on the edge or back side of the corrector and mirror.
Dwight


Well even if the corrector is marked and you forget to mark the
secondary, could you remove and replace the corrector 3 times
to determine which position is the best view by rotating the secondary one
screw position
each time wearing latex gloves? It would be a pain but it could be done I
should think.