Pick 2 from 5 of these scopes:

[garryblueboy]

Looking at your Scope line up and Budget you probably won’t find a refractor to beat a C9.25  there  but there are some that can but cost a lot more also the pictures of Saturn you refer too are these taken in the uk as Damien Peach most of his are in Places like Barbados  I have had three C9.25 and really didn’t think they lived up to the hype .

[johnturley]

On 16/03/2024 at 15:59, mikeDnight said:

Most definitely! I've seen a 120ED give significantly better lunar views than an excellent 200mm Dob; so much so in fact that the observers I was with were in disbelief at first. Then when both scopes were aimed at Saturn, the air turned blue with expletives, as they learned an important lesson - aperture isn't always King!

My Esprit 150 gives sharper planetary views than my 14in Newtonian on the majority of nights, although the the colour of the GRS, and the blackness of satellite shadow transits show up better through the 14in.

John 

[johnturley]

On 16/03/2024 at 16:22, Earl said:

If you could guratee the quality of the scopes howver I am very aware of a very large amount of variance in both the C9.25 and C11 a good C9.25 will outperform an average C11

Some observers used to claim that the C9.25 was superior to the C11 on planets, due to the longer (f2.5) focal ratio of the primary mirror, would be interested to hear from someone who has compared the two scopes.

John 

[johnturley]

On 16/03/2024 at 15:59, Flame Nebula said:

Hi Earl, 

Do you know if FLO will hand pick? If not, who would do that? 

Thanks 

You could ask whether Rother Valley Optics could carry out a Zygo test on a C9.25 purchased from them, or whether they would allow you to reject the scope if it did not come up to the expected standard.

I had a Zygo test carried out on my Tak 100 DZ, and the Strehl Ratio came out at 0.987, they informed me that if it didn't come up to the expected standard, then the scope is sent back to Takahashi

John 

[Earl]

1 hour ago, johnturley said:

Some observers used to claim that the C9.25 was superior to the C11 on planets, due to the longer (f2.5) focal ratio of the primary mirror, would be interested to hear from someone who has compared the two scopes.

John 

I never did a side by side of those, just the 9.25 and 180

[John]

3 hours ago, johnturley said:

You could ask whether Rother Valley Optics could carry out a Zygo test on a C9.25 purchased from them, or whether they would allow you to reject the scope if it did not come up to the expected standard.....

 

That begs the question of what the expected / reasonable standard is for a mass produced scope ?

Practically all of them would claim to be "diffraction limited" but as I understand it, that's not too high a bar. How much above that would it be reasonable to expect from an "average" and acceptable example of an instrument ?

Then there is the issue of system strehl vs primary strehl ......... maybe best not to go there ! 🙄

Edited March 19 by John