14" newtonian mirror

Hi,

where can I find 14" (or so) newtonian mirror only? How much
does it cost?

I plan to build the tube and mount and just get the mirror
to save bucks and shipping costs as I live in another
country and getting a giant complete newtonian package
would cost so much.

Thanks.

Wat

Watclod wrote:
Hi,

where can I find 14" (or so) newtonian mirror only? How much
does it cost?

I plan to build the tube and mount and just get the mirror
to save bucks and shipping costs as I live in another
country and getting a giant complete newtonian package
would cost so much.

Thanks.

Wat


You may wish to check R.F. Royce's website. I've frequently observed
through his 12.5" mirrors and they are very good.

Uncle Bob wrote:
Watclod wrote:
Hi,

where can I find 14" (or so) newtonian mirror only? How much
does it cost?

I plan to build the tube and mount and just get the mirror
to save bucks and shipping costs as I live in another
country and getting a giant complete newtonian package
would cost so much.

Thanks.

Wat


You may wish to check R.F. Royce's website. I've frequently observed
through his 12.5" mirrors and they are very good.


He is selling 8" mirror only for $1600 and "10 for $2200
whereas celestron 8" OTA is $800 and 9.25" is 1,000. Is he
out of his mind?

Anyone know where to get newtonian mirror only 14" for like
700 or so?? Royce stuff seems to be cassegrains. This may
be more expensive than newtonians.

Wat

check discovery telescopes website. they have great choices in mirrors.
they have an especially good deal on a 13.1 inch f 4.5 mirror. lots of
bang for the buck. i've always read good things about discovery mirrors.

Watclod wrote:
Uncle Bob wrote:

Watclod wrote:

Hi,

where can I find 14" (or so) newtonian mirror only? How much
does it cost?

I plan to build the tube and mount and just get the mirror
to save bucks and shipping costs as I live in another
country and getting a giant complete newtonian package
would cost so much.

Thanks.

Wat


You may wish to check R.F. Royce's website. I've frequently observed
through his 12.5" mirrors and they are very good.



He is selling 8" mirror only for $1600 and "10 for $2200
whereas celestron 8" OTA is $800 and 9.25" is 1,000. Is he
out of his mind?

Anyone know where to get newtonian mirror only 14" for like
700 or so?? Royce stuff seems to be cassegrains. This may
be more expensive than newtonians.

His newtonian mirrors are on this page.

http://www.rfroyce.com/stand_mirrors.htm

8" parabolic mirror, f8 to f5 is $725, not 1600.
And the following prices:
10" 795.00
12.5" 1,295
15" 1,990
16" 2,500
These prices are actually competitive with hand figured newtonian
optics of high quality produced in the US.
Mass produced SCT optics are cheaper. But you said you wanted a
newtonian. Most newtonian fanciers would have no problem paying $3,000
for a top-notch 18" primary.
Another approach might be to buy a chinese primary, and re-polish
and figure it yourself.
Clear Skies
Uncle Bob

Uncle Bob wrote:

Another approach might be to buy a chinese primary, and
re-polish
and figure it yourself.
Clear Skies
Uncle Bob

Have you any idea what is involved in refiguring a 14" parabolic mirror
to a higher standard than that offered in the first place? Then there's
the cost of re-aluminising. :-)

Assuming the Chinese offer a 14" mirror would that finished mirror be
cheaper than a glass mirror blank obtained locally? Who knows, in these
crazy upside-down economic times. ;-)

Regards
Chris.B

Watclod wrote:
Uncle Bob wrote:
Watclod wrote:
Hi,

where can I find 14" (or so) newtonian mirror only? How much
does it cost?

I plan to build the tube and mount and just get the mirror
to save bucks and shipping costs as I live in another
country and getting a giant complete newtonian package
would cost so much.

Thanks.

Wat


You may wish to check R.F. Royce's website. I've frequently
observed
through his 12.5" mirrors and they are very good.


He is selling 8" mirror only for $1600 and "10 for $2200
whereas celestron 8" OTA is $800 and 9.25" is 1,000. Is he
out of his mind?

Anyone know where to get newtonian mirror only 14" for like
700 or so?? Royce stuff seems to be cassegrains. This may
be more expensive than newtonians.

Wat


$700 will get you a good 10" mirror with coating. a good parabolic
mirror will cost at least $10 per square inch plus the cost of the
substrate.

Ian Anderson
www.customopticalsystems.com

wrote:
Uncle Bob wrote:


Another approach might be to buy a chinese primary, and

re-polish

and figure it yourself.
Clear Skies
Uncle Bob


Have you any idea what is involved in refiguring a 14" parabolic mirror
to a higher standard than that offered in the first place? Then there's
the cost of re-aluminising. :-)

You don't know until you test it. Stripping is no big deal. The
problems would be if the surface is too rough, then you have to polish
it back to a sphere, most likely. But from a sphere, you could spend
maybe 2 hours with a subdiameter lap to parabolize it.
Let's say we spend 20 hours re-working the mirror. But we save 1500
USD, we're paying ourselves 75USD per hour for our trouble, and we get a
smooth, 1/8-1/10th wave mirror!


Assuming the Chinese offer a 14" mirror would that finished mirror be
cheaper than a glass mirror blank obtained locally? Who knows, in these
crazy upside-down economic times. ;-)

Last blank I bought--12.5"pyrex--was 200 US 3 years ago. It's the labor
that's the killer. By buying a chinese mirror, you save yourself
hogging out the curve and most of the polishing. If manufacturing is
going to china because the labor is cheaper, isn't it fair that we take
advantage of that while we're sitting here collecting unemployment? :-)

Clear Skies!
Uncle Bob

zaph wrote:
check discovery telescopes website. they have great choices in
mirrors.
they have an especially good deal on a 13.1 inch f 4.5 mirror. lots
of
bang for the buck. i've always read good things about discovery
mirrors.

http://www.discovery-telescopes.com/optics.html

Cool. Discovery is selling a 12.5" f/5 mirror only for $849. It
says it has 1/15 wave front RMS. Does this translate to 1/4.5 wave
error? Whats the formula again?

In the same site. There are many sizes of diagonal mirrors. What
sizes should I get?

I live in another country and just plan to get the mirror to
save shipping costs. I plan to build the tube and mount myself.
How do I begin?? Maybe for the simpliest. I can just use wires
frames. Is this called truss? Any good book about this? I wonder
if discovery includes the mirror bracket in the mirror price.
Anyone here who actually ordered a discovery mirror only? Does
it include a bracket?

Wat

"Watclod" writes:

In the same site. There are many sizes of diagonal mirrors. What
sizes should I get?

The free software "newt" will help you to design your scope and
calculate the optimal diagonal mirror size:
http://home.att.net/~dale.keller/atm...t/newtsoft.htm

I live in another country and just plan to get the mirror to
save shipping costs. I plan to build the tube and mount myself.
How do I begin?? Maybe for the simpliest. I can just use wires
frames. Is this called truss? Any good book about this?

David Kriege and Richard Berry: "The Dobsonian Telescope: A Practical
Manual for Building Large Aperture Telescopes"
http://www.willbell.com/tm/dobtel.htm

I wonder
if discovery includes the mirror bracket in the mirror price.

To mount the mirror you'll need a properly built mirror cell. It is
not included with the mirror. You can buy one or build one yourself.

I recommend that you start reding the Kriege & Berry book and playing
with the newt software before shopping telecope parts.

pej
--
Per Erik Jorde