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Orion Optics VX12 1/10pv

DRT

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Pig

Pig

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Fantastic looking scope Derek :thumbsup: I will be very interested to know how it performs as I will be going down the DOB route early in the new year.

I have always fancied one of these scopes and came very close to buying one when I was at the Astrofest :icon_biggrin:

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DRT

DRT

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OK - I have read the Zygo report but as I am not from the planet Zygo I really don't understand what I am reading.

Here are what appear to be some vital statistics:

  • PV Wavefront = 0.101 wave
  • PV = 63.66nm
  • rms=0.016 wave
  • AstMag=0.015 wave
  • Strehl=0.990
  • The diagrams show a peak to valley range of +0.0487 to -0.0519 wave

Does anyone know whether or not I should be pleased with that?

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DRT

DRT

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2 minutes ago, Mark at Beaufort said:

Derek glad you obtained your Orion VX10. From what I understand  the PV Wavefront means your mirror is 1/10th. The Strehl figure of 0.990 shows the mirror is excellent. I think you should be pleased. Well thats  MIHO.

Thanks, Mark.

I just read somewhere on the net that a perfect Strehl is 1.0 and 0.83 is considered good so I am indeed very pleased with the 0.99 :grin:

 

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DRT

DRT

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5 minutes ago, Pig said:

I believe Snow Whites mirror had a Strehl rating of 1.0 :icon_flower: Looks like we have a new nick name for you Derek xxx

Which of the Seven Dwarfs is it to be? :lol:

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nightfisher

nightfisher

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Looks like the small delay was worth the wait, that looks a superb dob, one thing i like about OO dobs is the base, it has a small foot print

all the best for a stunning first light

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Timebandit

Timebandit

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Hello DRT and congratulations. I hope overall you are very pleased with your new scope. I bet you can't wait to point it into those clear dark sky's that we occasionally have in the uk?. With regards to the mirror i read somewhere that a 1/10 pv mirror from OO uk is the minimum it will be so you may have something approaching even 1/11. I am not sure if we have a Astro telescope mathematics reading these posts who can decipher the zygo report that may be able to give you a precise figure for your individual mirror. Anyway enjoy the knowledge that you have a cracking scope?

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niallk

niallk

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Congrats on the scope - she's a beauty, and those mirror specs sound top notch.  My 15" is reported to be 0.97 Strehl and 1/38.5~ RMS wavefront error (OMI measure at 550nm).

Here's a link that might be of interest:

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

... has a summary table pasted below - I think you should be very pleased ;)

Screenshot_2016-07-09-20-09-51.png

Enjoy & best of luck,

-Niall 

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Paul73

Paul73

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The two sets of figures don't seem to tie up. Could be that we are comparing apples with oranges. Couldn't say which are correct.

But, either way, it looks like you have got a great mirror there. 

Paul

PS. It was the wicked queen who had the mirror......

 

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John

John

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These figures are for the primary mirror and on some cases only a single cross section of it in a particular wavelength of light. I've spoken to scope makers who feel that "whole system" performance tests would be a more useful comparison but I've only rarely seen those published for any scopes.

Orion Optics may have their faults but mirror making is their forte and mostly their primaries are slightly better than the quality that was specified (mine was specced at 1/8th wave PV but is actually very close to 1/9th wave). Their "base" quality is 1/6th wave PV but if you are buying new you might as well pay the modest amount for an upgrade to 1/8th or 1/10th wave to play to the companies strength.

Good figures from tests are one thing but the view through the scope, especially on targets that push the performance, are what really tells the story :icon_biggrin:

I'm sure the views through your new scope will tell a very positive story Derek :icon_biggrin:

 

 

 

 

 

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mdstuart

mdstuart

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I have ordered high pressure for my 50th birthday party next weekend so that should provide some clear skies for you to test that scope.

You have given my 1/4 wave 16 inch mirror a complex now.

MarkMark

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Paul73

Paul73

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1 hour ago, mdstuart said:

 

You have given my 1/4 wave 16 inch mirror a complex now.

MarkMark

Don't worry Mark. Your distant galaxies will still be faint and fuzzy irrespective of whether you are using a 1/4 or 1/15 wave mirror.?

Happy birthday for next week.

Paul

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Timebandit

Timebandit

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2 hours ago, mdstuart said:

I have ordered high pressure for my 50th birthday party next weekend so that should provide some clear skies for you to test that scope.

You have given my 1/4 wave 16 inch mirror a complex now.

MarkMark

 

Hi Mark ,maybe you could give your telescope mirror a polish with these super cleaning products on the market to make your mirror sparkle ,and therefore up the PV ?

Now there's a thought? I wounder how a dirty mirror effects the PV of a mirror and if there is a serious drop in PV from even a mildly dusty , or dirty mirror ??

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John

John

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Reflectivity certainly drops as time passes due to the coatings gradually deteriorating. I've seen an approximate % per annum figure given somewhere. I think PV / strehl etc is due to the figuring so should not alter over time.

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niallk

niallk

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That could possibly be a good example as to why PV is not a sufficient metric - imagine a silvered speck of dust on the mirror. If it was a half micron or so in diameter, it would cause the PV to be 1 lambda.  However, the RMS would be negligibly affected, and same with Strehl!

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mdstuart

mdstuart

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One day I will get a vx 16 mirror and do a test!

A better mirror keeps the light even from a fuzzy more together and hence makes fainter objects more visible.

My old 10 inch skywatcher at x500 could see as faint as the 16 inch at x300. If you go to x500 in the 16 inch the mirror makes even fuzzies so spread out there us no benefit from going above x300. So a good mirror helps you go deeper.

Mark

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jetstream

jetstream

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On 2016-07-09 at 10:57, DRT said:

OK - I have read the Zygo report but as I am not from the planet Zygo I really don't understand what I am reading.

Here are what appear to be some vital statistics:

  • PV Wavefront = 0.101 wave
  • PV = 63.66nm
  • rms=0.016 wave
  • AstMag=0.015 wave
  • Strehl=0.990
  • The diagrams show a peak to valley range of +0.0487 to -0.0519 wave

Does anyone know whether or not I should be pleased with that?

Derek you should be jumping up and down with excitement!! :grin:

These are excellent numbers and with them comes the assurance of a very smooth mirror...

RMS .016, Strehl .990 those are freakin' great numbers! you will have a very good MTF with this telescope..... Congrats Derek, Gerry

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