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300mm f6 Zygo results


Stu
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My mirrors are with OO currently for testing and re-coating. The 300mm was marked as 1/12th when I bought it, although I confess I was always dubious about the spec as it is above and beyond the normal 1/10th Ultragrade mirrors.

Apparently though it was a special order back in 2004. Barry was a little concerned about whether any change to the figure had occurred over that time, I guess 11 years is a long time and we are talking very small measurements here so it is to be expected.

Anyway, the answer is that, yes, the mirror has shifted slightly over the years, but still came out of the Zygo showing 1/11th pv with a Strehl of 0.993. Very nice I reckon!

The secondary flat has also measured very well in the double pass so should come out to a high spec too.

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Looking forward to getting this scope back together with its Planetary killer specs [emoji3]

Stu

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Thats a very nice mirror Stu :smiley:

OO usually better their target surface accuracy. Mine was bought as an 1/8th wave PV but the Zygo results show it's 1/9th wave. Not that I'm going to be able to tell the difference !

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thats a nice mirror Stu,i thought you had sufficient scopes? You just got a 16" dob what you will do with a 12"?

I am actually playing with an idea of having a 12 or 14" dob in F6 or F8 but thats only an idea :D

Of course I have too many scopes!

I've had the 12" for a while. It's just too big to take anywhere. The 16" will come to dark sites with me, the 12" will be a planetary/lunar/small bright DSO scope for home

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thats a nice mirror Stu,i thought you had sufficient scopes? You just got a 16" dob what you will do with a 12"?

I am actually playing with an idea of having a 12 or 14" dob in F6 or F8 but thats only an idea :D

I wouldn't go any bigger than 12" f6 personally. This scope is as tall as Shane's 16" f4, about 1.7m or so. It's a big beast.

This one has a 50mm secondary fitted so it won't fully illuminate 2" eyepieces, but that's missing the point of it. It's a planetary/mid to high power scope. I do have a 60mm mirror with it as an option but haven't felt the need to fit it.

An 8" f8 would be very nice though.

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