Author Topic: Looking for a 10" F8 mirror  (Read 206 times)

Frky Sherman

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Re: Looking for a 10" F8 mirror
« Reply #15 on: January 16, 2018, 12:43:43 AM »
Of course you're right, just had a brain bubble there for a minute. I find it hard to believe the numbers but I've not heard complaints about their quality whether they're really as fantastic as claimed or not. I haven't seen any independent third party testing of their mirrors, which is probably a good indicator.

swittetsakee

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Re: Looking for a 10" F8 mirror
« Reply #16 on: January 25, 2018, 12:51:33 PM »
Bvillebob, I would be interested in knowing where you are having your mirror done. What kind of time frame did they give you for completing it. Some of the premium makers we see quite often, have fairly long wait times.

breakagalkit

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Re: Looking for a 10" F8 mirror
« Reply #17 on: January 26, 2018, 04:48:23 AM »
Quote
Hi,

Orion do offer several quality options.

Commercial mirrors seem to have the same focal length:
6" F9

8" F8

10" F6.4

Or nominally those. Possibly due to having one curve generator for blanks.
Or because the geometry of reasonable secondaries works out OK.

Asking for a different sagitta may cost a bit more.

Cheers. Andrew.
I think it more likely they have grinding and smoothing tools of a given radius.
Fixed routines can be developed over time for production of "standard" focal lengths.
It also simplifies radius checking with an accurate template or spherometer at each stage.
The optical work required can be predicted with experience gained over time and mass production of identical units.
This would be based on machine stroke length and lateral adjustment with each grade of abrasive.
The smoothing and polishing machines would run all the time and the results should be known without checking.
It helps to de-skill the job as well as speed it up.
Only at the testing and figuring stage will greater care be required.
Normal selection of accuracy levels can be achieved simply by aiming for highest quality each time.
Those units units fail to meet the best quality are then demoted in rank/price rather than reworked to make them of the highest quality.
The amateur's usually haphazard methods would be far too time consuming for commercial optical production.

xacypcheati

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Re: Looking for a 10" F8 mirror
« Reply #18 on: January 26, 2018, 05:10:18 AM »
Quote
Quote

Royce Optics make 10" f/8 mirrors, both standards and conicals, for very reasonable prices.

http://www.rfroyce.c...nd_mirrors.htmClear skies!
Thomas, Denmark

Hi,

I will look into that when back in the UK.

I mounted the 14" mirror on some Rover car body damping foam on a piece of 18mm birch plywood without issues.

The simple mounting of the conical mirror appeals to me.

Cheers. Andrew.
If you have any plans for an equatorial mounting the conical form would be a desirable option.

inlaylale

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Re: Looking for a 10" F8 mirror
« Reply #19 on: January 30, 2018, 05:23:22 AM »
I would go with a Quartz 10" f6 with an optical window, no spider.

Mayur Wilson

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Re: Looking for a 10" F8 mirror
« Reply #20 on: January 31, 2018, 02:52:54 AM »
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I would go with a Quartz 10" f6 with an optical window, no spider.

Hi,

Sealing the tube also keeps things inside clean.

I have found a Sodium notch filter with blue Mercury roll off which does not affect daytime pictures. It came bare and just happens to fit in the mouth of my GX80, 25mm. So a 48mm one could be used at the bottom of a 2" focus tube as a permanent dust seal.

I suppose the optical window would be an expensive item.

Cheers. Andrew.

chuckgemslerswe

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Re: Looking for a 10" F8 mirror
« Reply #21 on: February 02, 2018, 03:56:22 PM »
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<p class="citation">Richard Whalen, on 25 Apr 2017 - 01:28 AM, said:<a href="https://www.cloudynights.com/index.php?app=forums&amp;module=forums&amp;section=findpost&amp;pid=7841947" rel="citation">[/url]<blockquote class="ipsBlockquote built" data-time="1493076531" data-cid="7841947" data-author="Richard Whalen">I would go with a Quartz 10" f6 with an optical window, no spider.
Hi,Sealing the tube also keeps things inside clean.I have found a Sodium notch filter with blue Mercury roll off which does not affect daytime pictures. It came bare and just happens to fit in the mouth of my GX80, 25mm. So a 48mm one could be used at the bottom of a 2" focus tube as a permanent dust seal.I suppose the optical window would be an expensive item.Cheers. Andrew.[/quote]Yes a window that size would indeed be EXPENSIVE unless of course one is capable of making it yourself....I had one made that was 7.3" edge to edge and it was about $1300us when all was said and done.....10"+ would be expensive indeed, quotes ran from $1200 to $6000 for 7.3"

outatnoha

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Re: Looking for a 10" F8 mirror
« Reply #22 on: February 08, 2018, 10:49:51 PM »
I remember that thread. How did that turn out, Greg? Do you notice any difference in performance? Was it worth it?

Mladen

Nick Ellis

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Re: Looking for a 10" F8 mirror
« Reply #23 on: February 09, 2018, 11:28:00 AM »
*****
Doggone- I never spent that much, not even close on any scope except my 7.1" Mak-Cass !?!?
(only reason, I couldn't buy all parts and substrates for less than what I paid)