Not only do almost none of the scopes even reach 1/4 wave P-V, they do it in red light. I'd hate to see the scopes tested in green light! Some well-regarded scopes are horrible. Variations across models is also common.

https://translate.google.com/translate?hl=en&sl=auto&tl=en&u=http%3A%2F%2Ffidgor.ru%2FObservers%2Ftest.html

On Friday, July 23, 2021 at 12:36:34 AM UTC-4, RichA wrote:
> Not only do almost none of the scopes even reach 1/4 wave P-V, they do it in red light. I'd hate to see the scopes tested in green light! Some well-regarded scopes are horrible. Variations across models is also common.
>
> https://translate.google.com/translate?hl=en&sl=auto&tl=en&u=http%3A%2F%2Ffidgor.ru%2FObservers%2Ftest.html

The important numbers are the RMS and the Strehl. The PV could be off due to only a small area of the optic being too high or low, which might not affect the image very much.

Even a mediocre telescope can be much better than no telescope, or a "perfect" telescope that one cannot afford.

The irony here is that the objective lenses in the much-maligned 60 or 70 mm refractors would probably test out fairly well. It's too bad that they don't gather all that much light.

On Friday, 23 July 2021 at 05:51:01 UTC-4, W wrote:
> On Friday, July 23, 2021 at 12:36:34 AM UTC-4, RichA wrote:
> > Not only do almost none of the scopes even reach 1/4 wave P-V, they do it in red light. I'd hate to see the scopes tested in green light! Some well-regarded scopes are horrible. Variations across models is also common.
> >
> > https://translate.google.com/translate?hl=en&sl=auto&tl=en&u=http%3A%2F%2Ffidgor.ru%2FObservers%2Ftest.html
> The important numbers are the RMS and the Strehl. The PV could be off due to only a small area of the optic being too high or low, which might not affect the image very much.
>
> Even a mediocre telescope can be much better than no telescope, or a "perfect" telescope that one cannot afford.
>
> The irony here is that the objective lenses in the much-maligned 60 or 70 mm refractors would probably test out fairly well. It's too bad that they don't gather all that much light.

He says it in one review, "small lenses are easy to make good." But there were surprises, like an 8 inch achromatic refractor objective (2400mm focal length) from China off Ebay that scored well.
But some of the "sacred cows" of the scope world (Intes Micro maks) didn't score well. There is another site (German) that does similar stuff.

http://astro-foren.com/index.php/de/schwerpunkt

On Friday, July 23, 2021 at 6:53:17 PM UTC-4, RichA wrote:
> On Friday, 23 July 2021 at 05:51:01 UTC-4, W wrote:
> > On Friday, July 23, 2021 at 12:36:34 AM UTC-4, RichA wrote:
> > > Not only do almost none of the scopes even reach 1/4 wave P-V, they do it in red light. I'd hate to see the scopes tested in green light! Some well-regarded scopes are horrible. Variations across models is also common.
> > >
> > > https://translate.google.com/translate?hl=en&sl=auto&tl=en&u=http%3A%2F%2Ffidgor.ru%2FObservers%2Ftest.html
> > The important numbers are the RMS and the Strehl. The PV could be off due to only a small area of the optic being too high or low, which might not affect the image very much.
> >
> > Even a mediocre telescope can be much better than no telescope, or a "perfect" telescope that one cannot afford.
> >
> > The irony here is that the objective lenses in the much-maligned 60 or 70 mm refractors would probably test out fairly well. It's too bad that they don't gather all that much light.
> He says it in one review, "small lenses are easy to make good." But there were surprises, like an 8 inch achromatic refractor objective (2400mm focal length) from China off Ebay that scored well.
> But some of the "sacred cows" of the scope world (Intes Micro maks) didn't score well. There is another site (German) that does similar stuff.
>
> http://astro-foren.com/index.php/de/schwerpunkt

Are these telescopes truly random samples or just ones that the owners suspect are defective?

On Saturday, 24 July 2021 at 08:23:49 UTC-4, W wrote:
> On Friday, July 23, 2021 at 6:53:17 PM UTC-4, RichA wrote:
> > On Friday, 23 July 2021 at 05:51:01 UTC-4, W wrote:
> > > On Friday, July 23, 2021 at 12:36:34 AM UTC-4, RichA wrote:
> > > > Not only do almost none of the scopes even reach 1/4 wave P-V, they do it in red light. I'd hate to see the scopes tested in green light! Some well-regarded scopes are horrible. Variations across models is also common.
> > > >
> > > > https://translate.google.com/translate?hl=en&sl=auto&tl=en&u=http%3A%2F%2Ffidgor.ru%2FObservers%2Ftest.html
> > > The important numbers are the RMS and the Strehl. The PV could be off due to only a small area of the optic being too high or low, which might not affect the image very much.
> > >
> > > Even a mediocre telescope can be much better than no telescope, or a "perfect" telescope that one cannot afford.
> > >
> > > The irony here is that the objective lenses in the much-maligned 60 or 70 mm refractors would probably test out fairly well. It's too bad that they don't gather all that much light.
> > He says it in one review, "small lenses are easy to make good." But there were surprises, like an 8 inch achromatic refractor objective (2400mm focal length) from China off Ebay that scored well.
> > But some of the "sacred cows" of the scope world (Intes Micro maks) didn't score well. There is another site (German) that does similar stuff.
> >
> > http://astro-foren.com/index.php/de/schwerpunkt
> Are these telescopes truly random samples or just ones that the owners suspect are defective?

Random, people just interested. I doubt someone sent in a TEC 160 with the idea it was defective.

On Saturday, July 24, 2021 at 9:46:06 PM UTC-4, RichA wrote:
> On Saturday, 24 July 2021 at 08:23:49 UTC-4, W wrote:
> > On Friday, July 23, 2021 at 6:53:17 PM UTC-4, RichA wrote:
> > > On Friday, 23 July 2021 at 05:51:01 UTC-4, W wrote:
> > > > On Friday, July 23, 2021 at 12:36:34 AM UTC-4, RichA wrote:
> > > > > Not only do almost none of the scopes even reach 1/4 wave P-V, they do it in red light. I'd hate to see the scopes tested in green light! Some well-regarded scopes are horrible. Variations across models is also common.
> > > > >
> > > > > https://translate.google.com/translate?hl=en&sl=auto&tl=en&u=http%3A%2F%2Ffidgor.ru%2FObservers%2Ftest.html
> > > > The important numbers are the RMS and the Strehl. The PV could be off due to only a small area of the optic being too high or low, which might not affect the image very much.
> > > >
> > > > Even a mediocre telescope can be much better than no telescope, or a "perfect" telescope that one cannot afford.
> > > >
> > > > The irony here is that the objective lenses in the much-maligned 60 or 70 mm refractors would probably test out fairly well. It's too bad that they don't gather all that much light.
> > > He says it in one review, "small lenses are easy to make good." But there were surprises, like an 8 inch achromatic refractor objective (2400mm focal length) from China off Ebay that scored well.
> > > But some of the "sacred cows" of the scope world (Intes Micro maks) didn't score well. There is another site (German) that does similar stuff.
> > >
> > > http://astro-foren.com/index.php/de/schwerpunkt
> > Are these telescopes truly random samples or just ones that the owners suspect are defective?
> Random, people just interested. I doubt someone sent in a TEC 160 with the idea it was defective.

The fact that someone brought in a $12K OTA has no relevance whatsoever to my question. All the other tested scopes that were 1/3 wave or worse are bound to seem lacking compared to any similar examples that seem sharper in real life. If your $400 OTA gives good images you probably won't waste time testing it.

On Saturday, 24 July 2021 at 22:50:09 UTC-4, W wrote:
> On Saturday, July 24, 2021 at 9:46:06 PM UTC-4, RichA wrote:
> > On Saturday, 24 July 2021 at 08:23:49 UTC-4, W wrote:
> > > On Friday, July 23, 2021 at 6:53:17 PM UTC-4, RichA wrote:
> > > > On Friday, 23 July 2021 at 05:51:01 UTC-4, W wrote:
> > > > > On Friday, July 23, 2021 at 12:36:34 AM UTC-4, RichA wrote:
> > > > > > Not only do almost none of the scopes even reach 1/4 wave P-V, they do it in red light. I'd hate to see the scopes tested in green light! Some well-regarded scopes are horrible. Variations across models is also common.
> > > > > >
> > > > > > https://translate.google.com/translate?hl=en&sl=auto&tl=en&u=http%3A%2F%2Ffidgor.ru%2FObservers%2Ftest.html
> > > > > The important numbers are the RMS and the Strehl. The PV could be off due to only a small area of the optic being too high or low, which might not affect the image very much.
> > > > >
> > > > > Even a mediocre telescope can be much better than no telescope, or a "perfect" telescope that one cannot afford.
> > > > >
> > > > > The irony here is that the objective lenses in the much-maligned 60 or 70 mm refractors would probably test out fairly well. It's too bad that they don't gather all that much light.
> > > > He says it in one review, "small lenses are easy to make good." But there were surprises, like an 8 inch achromatic refractor objective (2400mm focal length) from China off Ebay that scored well.
> > > > But some of the "sacred cows" of the scope world (Intes Micro maks) didn't score well. There is another site (German) that does similar stuff.
> > > >
> > > > http://astro-foren.com/index.php/de/schwerpunkt
> > > Are these telescopes truly random samples or just ones that the owners suspect are defective?
> > Random, people just interested. I doubt someone sent in a TEC 160 with the idea it was defective.
> The fact that someone brought in a $12K OTA has no relevance whatsoever to my question. All the other tested scopes that were 1/3 wave or worse are bound to seem lacking compared to any similar examples that seem sharper in real life. If your $400 OTA gives good images you probably won't waste time testing it.

Unless you are curious and someone offers.

On Sunday, July 25, 2021 at 10:17:21 PM UTC-4, RichA wrote:
> On Saturday, 24 July 2021 at 22:50:09 UTC-4, W wrote:
> > On Saturday, July 24, 2021 at 9:46:06 PM UTC-4, RichA wrote:
> > > On Saturday, 24 July 2021 at 08:23:49 UTC-4, W wrote:
> > > > On Friday, July 23, 2021 at 6:53:17 PM UTC-4, RichA wrote:
> > > > > On Friday, 23 July 2021 at 05:51:01 UTC-4, W wrote:
> > > > > > On Friday, July 23, 2021 at 12:36:34 AM UTC-4, RichA wrote:
> > > > > > > Not only do almost none of the scopes even reach 1/4 wave P-V, they do it in red light. I'd hate to see the scopes tested in green light! Some well-regarded scopes are horrible. Variations across models is also common.
> > > > > > >
> > > > > > > https://translate.google.com/translate?hl=en&sl=auto&tl=en&u=http%3A%2F%2Ffidgor.ru%2FObservers%2Ftest.html
> > > > > > The important numbers are the RMS and the Strehl. The PV could be off due to only a small area of the optic being too high or low, which might not affect the image very much.
> > > > > >
> > > > > > Even a mediocre telescope can be much better than no telescope, or a "perfect" telescope that one cannot afford.
> > > > > >
> > > > > > The irony here is that the objective lenses in the much-maligned 60 or 70 mm refractors would probably test out fairly well. It's too bad that they don't gather all that much light.
> > > > > He says it in one review, "small lenses are easy to make good." But there were surprises, like an 8 inch achromatic refractor objective (2400mm focal length) from China off Ebay that scored well.
> > > > > But some of the "sacred cows" of the scope world (Intes Micro maks) didn't score well. There is another site (German) that does similar stuff.
> > > > >
> > > > > http://astro-foren.com/index.php/de/schwerpunkt
> > > > Are these telescopes truly random samples or just ones that the owners suspect are defective?
> > > Random, people just interested. I doubt someone sent in a TEC 160 with the idea it was defective.
> > The fact that someone brought in a $12K OTA has no relevance whatsoever to my question. All the other tested scopes that were 1/3 wave or worse are bound to seem lacking compared to any similar examples that seem sharper in real life. If your $400 OTA gives good images you probably won't waste time testing it.
> Unless you are curious and someone offers.

That's not relevant.

Are the tested telescopes representative of each of the telescope models?
Are the tested telescopes representative of the population of telescopes as a whole?

If either of the above are not the case, then this exercise is pointless, except to the individual owner who might be inspired to return a telescope that he already thought was defective.

On Monday, 26 July 2021 at 06:43:10 UTC-4, W wrote:
> On Sunday, July 25, 2021 at 10:17:21 PM UTC-4, RichA wrote:
> > On Saturday, 24 July 2021 at 22:50:09 UTC-4, W wrote:
> > > On Saturday, July 24, 2021 at 9:46:06 PM UTC-4, RichA wrote:
> > > > On Saturday, 24 July 2021 at 08:23:49 UTC-4, W wrote:
> > > > > On Friday, July 23, 2021 at 6:53:17 PM UTC-4, RichA wrote:
> > > > > > On Friday, 23 July 2021 at 05:51:01 UTC-4, W wrote:
> > > > > > > On Friday, July 23, 2021 at 12:36:34 AM UTC-4, RichA wrote:
> > > > > > > > Not only do almost none of the scopes even reach 1/4 wave P-V, they do it in red light. I'd hate to see the scopes tested in green light! Some well-regarded scopes are horrible. Variations across models is also common.
> > > > > > > >
> > > > > > > > https://translate.google.com/translate?hl=en&sl=auto&tl=en&u=http%3A%2F%2Ffidgor.ru%2FObservers%2Ftest.html
> > > > > > > The important numbers are the RMS and the Strehl. The PV could be off due to only a small area of the optic being too high or low, which might not affect the image very much.
> > > > > > >
> > > > > > > Even a mediocre telescope can be much better than no telescope, or a "perfect" telescope that one cannot afford.
> > > > > > >
> > > > > > > The irony here is that the objective lenses in the much-maligned 60 or 70 mm refractors would probably test out fairly well. It's too bad that they don't gather all that much light.
> > > > > > He says it in one review, "small lenses are easy to make good." But there were surprises, like an 8 inch achromatic refractor objective (2400mm focal length) from China off Ebay that scored well.
> > > > > > But some of the "sacred cows" of the scope world (Intes Micro maks) didn't score well. There is another site (German) that does similar stuff.
> > > > > >
> > > > > > http://astro-foren.com/index.php/de/schwerpunkt
> > > > > Are these telescopes truly random samples or just ones that the owners suspect are defective?
> > > > Random, people just interested. I doubt someone sent in a TEC 160 with the idea it was defective.
> > > The fact that someone brought in a $12K OTA has no relevance whatsoever to my question. All the other tested scopes that were 1/3 wave or worse are bound to seem lacking compared to any similar examples that seem sharper in real life. If your $400 OTA gives good images you probably won't waste time testing it.
> > Unless you are curious and someone offers.
> That's not relevant.
>
> Are the tested telescopes representative of each of the telescope models?
> Are the tested telescopes representative of the population of telescopes as a whole?
>
> If either of the above are not the case, then this exercise is pointless, except to the individual owner who might be inspired to return a telescope that he already thought was defective.

I would say, given the mass production of scopes today, whatever is tested is likely representative of what you might buy. I once tested 32 Meade ETX-90 telescopes in a row (took five hours) and you really could see no noticeable difference between them. Such is the case with computerized, mass-production.

On Monday, July 26, 2021 at 6:22:05 PM UTC-4, RichA wrote:
> On Monday, 26 July 2021 at 06:43:10 UTC-4, W wrote:
> > On Sunday, July 25, 2021 at 10:17:21 PM UTC-4, RichA wrote:
> > > On Saturday, 24 July 2021 at 22:50:09 UTC-4, W wrote:
> > > > On Saturday, July 24, 2021 at 9:46:06 PM UTC-4, RichA wrote:
> > > > > On Saturday, 24 July 2021 at 08:23:49 UTC-4, W wrote:
> > > > > > On Friday, July 23, 2021 at 6:53:17 PM UTC-4, RichA wrote:
> > > > > > > On Friday, 23 July 2021 at 05:51:01 UTC-4, W wrote:
> > > > > > > > On Friday, July 23, 2021 at 12:36:34 AM UTC-4, RichA wrote:
> > > > > > > > > Not only do almost none of the scopes even reach 1/4 wave P-V, they do it in red light. I'd hate to see the scopes tested in green light! Some well-regarded scopes are horrible. Variations across models is also common.
> > > > > > > > >
> > > > > > > > > https://translate.google.com/translate?hl=en&sl=auto&tl=en&u=http%3A%2F%2Ffidgor.ru%2FObservers%2Ftest.html
> > > > > > > > The important numbers are the RMS and the Strehl. The PV could be off due to only a small area of the optic being too high or low, which might not affect the image very much.
> > > > > > > >
> > > > > > > > Even a mediocre telescope can be much better than no telescope, or a "perfect" telescope that one cannot afford.
> > > > > > > >
> > > > > > > > The irony here is that the objective lenses in the much-maligned 60 or 70 mm refractors would probably test out fairly well. It's too bad that they don't gather all that much light.
> > > > > > > He says it in one review, "small lenses are easy to make good.." But there were surprises, like an 8 inch achromatic refractor objective (2400mm focal length) from China off Ebay that scored well.
> > > > > > > But some of the "sacred cows" of the scope world (Intes Micro maks) didn't score well. There is another site (German) that does similar stuff.
> > > > > > >
> > > > > > > http://astro-foren.com/index.php/de/schwerpunkt
> > > > > > Are these telescopes truly random samples or just ones that the owners suspect are defective?
> > > > > Random, people just interested. I doubt someone sent in a TEC 160 with the idea it was defective.
> > > > The fact that someone brought in a $12K OTA has no relevance whatsoever to my question. All the other tested scopes that were 1/3 wave or worse are bound to seem lacking compared to any similar examples that seem sharper in real life. If your $400 OTA gives good images you probably won't waste time testing it.
> > > Unless you are curious and someone offers.
> > That's not relevant.
> >
> > Are the tested telescopes representative of each of the telescope models?
> > Are the tested telescopes representative of the population of telescopes as a whole?
> >
> > If either of the above are not the case, then this exercise is pointless, except to the individual owner who might be inspired to return a telescope that he already thought was defective.
> I would say, given the mass production of scopes today, whatever is tested is likely representative of what you might buy. I once tested 32 Meade ETX-90 telescopes in a row (took five hours) and you really could see no noticeable difference between them. Such is the case >with computerized, mass-production.

//

What were the P/V, RMS and Strehl results on those ETX-90s?

There were no ETX-90s in the link you gave. I have not heard anything bad about the optics in those; they seem to give Questars a run for the money, considering the price difference. There were some 125s in there, two "bad" and one great. Maybe those two were not representative.

On Monday, 26 July 2021 at 20:08:58 UTC-4, W wrote:
> On Monday, July 26, 2021 at 6:22:05 PM UTC-4, RichA wrote:
> > On Monday, 26 July 2021 at 06:43:10 UTC-4, W wrote:
> > > On Sunday, July 25, 2021 at 10:17:21 PM UTC-4, RichA wrote:
> > > > On Saturday, 24 July 2021 at 22:50:09 UTC-4, W wrote:
> > > > > On Saturday, July 24, 2021 at 9:46:06 PM UTC-4, RichA wrote:
> > > > > > On Saturday, 24 July 2021 at 08:23:49 UTC-4, W wrote:
> > > > > > > On Friday, July 23, 2021 at 6:53:17 PM UTC-4, RichA wrote:
> > > > > > > > On Friday, 23 July 2021 at 05:51:01 UTC-4, W wrote:
> > > > > > > > > On Friday, July 23, 2021 at 12:36:34 AM UTC-4, RichA wrote:
> > > > > > > > > > Not only do almost none of the scopes even reach 1/4 wave P-V, they do it in red light. I'd hate to see the scopes tested in green light! Some well-regarded scopes are horrible. Variations across models is also common.
> > > > > > > > > >
> > > > > > > > > > https://translate.google.com/translate?hl=en&sl=auto&tl=en&u=http%3A%2F%2Ffidgor.ru%2FObservers%2Ftest.html
> > > > > > > > > The important numbers are the RMS and the Strehl. The PV could be off due to only a small area of the optic being too high or low, which might not affect the image very much.
> > > > > > > > >
> > > > > > > > > Even a mediocre telescope can be much better than no telescope, or a "perfect" telescope that one cannot afford.
> > > > > > > > >
> > > > > > > > > The irony here is that the objective lenses in the much-maligned 60 or 70 mm refractors would probably test out fairly well. It's too bad that they don't gather all that much light.
> > > > > > > > He says it in one review, "small lenses are easy to make good." But there were surprises, like an 8 inch achromatic refractor objective (2400mm focal length) from China off Ebay that scored well.
> > > > > > > > But some of the "sacred cows" of the scope world (Intes Micro maks) didn't score well. There is another site (German) that does similar stuff.
> > > > > > > >
> > > > > > > > http://astro-foren.com/index.php/de/schwerpunkt
> > > > > > > Are these telescopes truly random samples or just ones that the owners suspect are defective?
> > > > > > Random, people just interested. I doubt someone sent in a TEC 160 with the idea it was defective.
> > > > > The fact that someone brought in a $12K OTA has no relevance whatsoever to my question. All the other tested scopes that were 1/3 wave or worse are bound to seem lacking compared to any similar examples that seem sharper in real life. If your $400 OTA gives good images you probably won't waste time testing it.
> > > > Unless you are curious and someone offers.
> > > That's not relevant.
> > >
> > > Are the tested telescopes representative of each of the telescope models?
> > > Are the tested telescopes representative of the population of telescopes as a whole?
> > >
> > > If either of the above are not the case, then this exercise is pointless, except to the individual owner who might be inspired to return a telescope that he already thought was defective.
> > I would say, given the mass production of scopes today, whatever is tested is likely representative of what you might buy. I once tested 32 Meade ETX-90 telescopes in a row (took five hours) and you really could see no noticeable difference between them. Such is the case >with computerized, mass-production.
> //
>
> What were the P/V, RMS and Strehl results on those ETX-90s?
>
> There were no ETX-90s in the link you gave. I have not heard anything bad about the optics in those; they seem to give Questars a run for the money, considering the price difference. There were some 125s in there, two "bad" and one great. Maybe those two were not representative.

No, no ETX 90s in the test. I do believe there are bad ETX125s just like the Intes Maks in tests. There was a natural connection to worse tests for larger scopes, which makes sense. Though a considerably larger scope has to be pretty bad to not "beat" a good smaller scope on planets or deepsky objects.

https://i.kym-cdn.com/photos/images/original/001/585/846/b1b.jpg

On Tuesday, July 27, 2021 at 12:07:30 AM UTC-4, RichA wrote:
> On Monday, 26 July 2021 at 20:08:58 UTC-4, W wrote:
> > On Monday, July 26, 2021 at 6:22:05 PM UTC-4, RichA wrote:
> > > On Monday, 26 July 2021 at 06:43:10 UTC-4, W wrote:
> > > > On Sunday, July 25, 2021 at 10:17:21 PM UTC-4, RichA wrote:
> > > > > On Saturday, 24 July 2021 at 22:50:09 UTC-4, W wrote:
> > > > > > On Saturday, July 24, 2021 at 9:46:06 PM UTC-4, RichA wrote:
> > > > > > > On Saturday, 24 July 2021 at 08:23:49 UTC-4, W wrote:
> > > > > > > > On Friday, July 23, 2021 at 6:53:17 PM UTC-4, RichA wrote:
> > > > > > > > > On Friday, 23 July 2021 at 05:51:01 UTC-4, W wrote:
> > > > > > > > > > On Friday, July 23, 2021 at 12:36:34 AM UTC-4, RichA wrote:
> > > > > > > > > > > Not only do almost none of the scopes even reach 1/4 wave P-V, they do it in red light. I'd hate to see the scopes tested in green light! Some well-regarded scopes are horrible. Variations across models is also common.
> > > > > > > > > > >
> > > > > > > > > > > https://translate.google.com/translate?hl=en&sl=auto&tl=en&u=http%3A%2F%2Ffidgor.ru%2FObservers%2Ftest.html
> > > > > > > > > > The important numbers are the RMS and the Strehl. The PV could be off due to only a small area of the optic being too high or low, which might not affect the image very much.
> > > > > > > > > >
> > > > > > > > > > Even a mediocre telescope can be much better than no telescope, or a "perfect" telescope that one cannot afford.
> > > > > > > > > >
> > > > > > > > > > The irony here is that the objective lenses in the much-maligned 60 or 70 mm refractors would probably test out fairly well. It's too bad that they don't gather all that much light.
> > > > > > > > > He says it in one review, "small lenses are easy to make good." But there were surprises, like an 8 inch achromatic refractor objective (2400mm focal length) from China off Ebay that scored well.
> > > > > > > > > But some of the "sacred cows" of the scope world (Intes Micro maks) didn't score well. There is another site (German) that does similar stuff.
> > > > > > > > >
> > > > > > > > > http://astro-foren.com/index.php/de/schwerpunkt
> > > > > > > > Are these telescopes truly random samples or just ones that the owners suspect are defective?
> > > > > > > Random, people just interested. I doubt someone sent in a TEC 160 with the idea it was defective.
> > > > > > The fact that someone brought in a $12K OTA has no relevance whatsoever to my question. All the other tested scopes that were 1/3 wave or worse are bound to seem lacking compared to any similar examples that seem sharper in real life. If your $400 OTA gives good images you probably won't waste time testing it.
> > > > > Unless you are curious and someone offers.
> > > > That's not relevant.
> > > >
> > > > Are the tested telescopes representative of each of the telescope models?
> > > > Are the tested telescopes representative of the population of telescopes as a whole?
> > > >
> > > > If either of the above are not the case, then this exercise is pointless, except to the individual owner who might be inspired to return a telescope that he already thought was defective.
> > > I would say, given the mass production of scopes today, whatever is tested is likely representative of what you might buy. I once tested 32 Meade ETX-90 telescopes in a row (took five hours) and you really could see no noticeable difference between them. Such is the case >with computerized, mass-production.
> > //
> >
> > What were the P/V, RMS and Strehl results on those ETX-90s?
> >
> > There were no ETX-90s in the link you gave. I have not heard anything bad about the optics in those; they seem to give Questars a run for the money, considering the price difference. There were some 125s in there, two "bad" and one great. Maybe those two were not representative.
> No, no ETX 90s in the test. I do believe there are bad ETX125s just like the Intes Maks in tests. There was a natural connection to worse tests for larger scopes, which makes sense. Though a considerably larger scope has to be pretty bad to not "beat" a good smaller scope >on planets or deepsky objects.

[[[[[[[[[

I tallied up the results for all of the examples of a particular telescope model that enjoys a good reputation. Half were good, a few were so-so and a couple of them looked bad, based on the numbers. If 25% of them were sub-par, then the rep of the model would not be that good. I have to conclude that the tested telescopes are not representative of their respective types and models. The site does show that bad examples of some models are possible and that maybe good examples exist too. That isn't news.

Maybe ETX90s are rare in Russia. Maybe ETX90s have such good QC that owners have no reason to want to test them. The same lack of curiosity could apply to the owners of many individual telescopes, even if a few of those types or models have some number of dogs among them.

That old Sky and Telescope article wherein 1- , 1/2, 1/4, 1/10-wave telescopes tested side-by-side under the night sky should shed some light on this. The 1-wave and 1/2-wave telescopes were easy to identify. The 1/4 and 1/10-wave telescopes were more difficult to distinguish from each other.

On Tuesday, July 27, 2021 at 12:07:30 AM UTC-4, RichA wrote:
> On Monday, 26 July 2021 at 20:08:58 UTC-4, W wrote:
> > On Monday, July 26, 2021 at 6:22:05 PM UTC-4, RichA wrote:
> > > On Monday, 26 July 2021 at 06:43:10 UTC-4, W wrote:
> > > > On Sunday, July 25, 2021 at 10:17:21 PM UTC-4, RichA wrote:
> > > > > On Saturday, 24 July 2021 at 22:50:09 UTC-4, W wrote:
> > > > > > On Saturday, July 24, 2021 at 9:46:06 PM UTC-4, RichA wrote:
> > > > > > > On Saturday, 24 July 2021 at 08:23:49 UTC-4, W wrote:
> > > > > > > > On Friday, July 23, 2021 at 6:53:17 PM UTC-4, RichA wrote:
> > > > > > > > > On Friday, 23 July 2021 at 05:51:01 UTC-4, W wrote:
> > > > > > > > > > On Friday, July 23, 2021 at 12:36:34 AM UTC-4, RichA wrote:
> > > > > > > > > > > Not only do almost none of the scopes even reach 1/4 wave P-V, they do it in red light. I'd hate to see the scopes tested in green light! Some well-regarded scopes are horrible. Variations across models is also common.
> > > > > > > > > > >
> > > > > > > > > > > https://translate.google.com/translate?hl=en&sl=auto&tl=en&u=http%3A%2F%2Ffidgor.ru%2FObservers%2Ftest.html
> > > > > > > > > > The important numbers are the RMS and the Strehl. The PV could be off due to only a small area of the optic being too high or low, which might not affect the image very much.
> > > > > > > > > >
> > > > > > > > > > Even a mediocre telescope can be much better than no telescope, or a "perfect" telescope that one cannot afford.
> > > > > > > > > >
> > > > > > > > > > The irony here is that the objective lenses in the much-maligned 60 or 70 mm refractors would probably test out fairly well. It's too bad that they don't gather all that much light.
> > > > > > > > > He says it in one review, "small lenses are easy to make good." But there were surprises, like an 8 inch achromatic refractor objective (2400mm focal length) from China off Ebay that scored well.
> > > > > > > > > But some of the "sacred cows" of the scope world (Intes Micro maks) didn't score well. There is another site (German) that does similar stuff.
> > > > > > > > >
> > > > > > > > > http://astro-foren.com/index.php/de/schwerpunkt
> > > > > > > > Are these telescopes truly random samples or just ones that the owners suspect are defective?
> > > > > > > Random, people just interested. I doubt someone sent in a TEC 160 with the idea it was defective.
> > > > > > The fact that someone brought in a $12K OTA has no relevance whatsoever to my question. All the other tested scopes that were 1/3 wave or worse are bound to seem lacking compared to any similar examples that seem sharper in real life. If your $400 OTA gives good images you probably won't waste time testing it.
> > > > > Unless you are curious and someone offers.
> > > > That's not relevant.
> > > >
> > > > Are the tested telescopes representative of each of the telescope models?
> > > > Are the tested telescopes representative of the population of telescopes as a whole?
> > > >
> > > > If either of the above are not the case, then this exercise is pointless, except to the individual owner who might be inspired to return a telescope that he already thought was defective.
> > > I would say, given the mass production of scopes today, whatever is tested is likely representative of what you might buy. I once tested 32 Meade ETX-90 telescopes in a row (took five hours) and you really could see no noticeable difference between them. Such is the case >with computerized, mass-production.
> > //
> >
> > What were the P/V, RMS and Strehl results on those ETX-90s?
> >
> > There were no ETX-90s in the link you gave. I have not heard anything bad about the optics in those; they seem to give Questars a run for the money, considering the price difference. There were some 125s in there, two "bad" and one great. Maybe those two were not representative.
> No, no ETX 90s in the test. I do believe there are bad ETX125s just like the Intes Maks in tests. There was a natural connection to worse tests for larger scopes, which makes sense. Though a considerably larger scope has to be pretty bad to not "beat" a good smaller scope >on planets or deepsky objects.

I tallied up the results for all of the examples of a particular telescope model that enjoys a good reputation. Half were good, a few were so-so and a couple of them looked bad, based on the numbers. If 25% of them were sub-par, then the rep of the model would not be that good. I have to conclude that the tested telescopes are not representative of their respective types and models. The site does show that bad examples of some models are possible and that maybe good examples exist too. That isn't news.

Maybe ETX90s are rare in Russia. Maybe ETX90s have such good QC that owners have no reason to want to test them. The same lack of curiosity could apply to the owners of many individual telescopes, even if a few of those types or models have some number of dogs among them.

That old Sky and Telescope article wherein 1- , 1/2, 1/4, 1/10-wave telescopes were tested side-by-side under the night sky should shed some light on this. The 1-wave and 1/2-wave telescopes were easy to identify. The 1/4 and 1/10-wave telescopes were more difficult to distinguish from each other.

https://www.google.com/search?q=greta+thunberg+how+dare+you&client=firefox-b-1-d&ei=i7MBYfi6Ms_F-gT5y4HYAw&oq=greta+thunberg+h&gs_lcp=Cgdnd3Mtd2l6EAEYADICCAAyAggAMgIIADICCAAyAggAMgIIADICCAAyAggAMgIIADICCAA6BwgAELADEEM6CggAELEDELADEEM6CgguELADEMgDEEM6CwguELEDELADEMgDOgcIABCxAxBDOgUIABCxAzoECAAQQ0oFCDgSATFKBAhBGAFQpgdYmxNg3CtoAHAAeACAAbECiAGMBpIBBzAuMy4wLjGYAQCgAQGqAQdnd3Mtd2l6yAENwAEB&sclient=gws-wiz#kpvalbx=_krMBYdOfMYbb-wT1kZzIAw43
"W" wrote in message
news:747ffdb8-264b-46c2-903c-9d213c982b2an@googlegroups.com...

On Tuesday, July 27, 2021 at 12:07:30 AM UTC-4, RichA wrote:
> On Monday, 26 July 2021 at 20:08:58 UTC-4, W wrote:
> > On Monday, July 26, 2021 at 6:22:05 PM UTC-4, RichA wrote:
> > > On Monday, 26 July 2021 at 06:43:10 UTC-4, W wrote:
> > > > On Sunday, July 25, 2021 at 10:17:21 PM UTC-4, RichA wrote:
> > > > > On Saturday, 24 July 2021 at 22:50:09 UTC-4, W wrote:
> > > > > > On Saturday, July 24, 2021 at 9:46:06 PM UTC-4, RichA wrote:
> > > > > > > On Saturday, 24 July 2021 at 08:23:49 UTC-4, W wrote:
> > > > > > > > On Friday, July 23, 2021 at 6:53:17 PM UTC-4, RichA wrote:
> > > > > > > > > On Friday, 23 July 2021 at 05:51:01 UTC-4, W wrote:
> > > > > > > > > > On Friday, July 23, 2021 at 12:36:34 AM UTC-4, RichA
> > > > > > > > > > wrote:
> > > > > > > > > > > Not only do almost none of the scopes even reach 1/4
> > > > > > > > > > > wave P-V, they do it in red light. I'd hate to see the
> > > > > > > > > > > scopes tested in green light! Some well-regarded
> > > > > > > > > > > scopes are horrible. Variations across models is also
> > > > > > > > > > > common.
> > > > > > > > > > >
> > > > > > > > > > > https://translate.google.com/translate?hl=en&sl=auto&tl=en&u=http%3A%2F%2Ffidgor.ru%2FObservers%2Ftest.html
> > > > > > > > > > The important numbers are the RMS and the Strehl. The PV
> > > > > > > > > > could be off due to only a small area of the optic being
> > > > > > > > > > too high or low, which might not affect the image very
> > > > > > > > > > much.
> > > > > > > > > >
> > > > > > > > > > Even a mediocre telescope can be much better than no
> > > > > > > > > > telescope, or a "perfect" telescope that one cannot
> > > > > > > > > > afford.
> > > > > > > > > >
> > > > > > > > > > The irony here is that the objective lenses in the
> > > > > > > > > > much-maligned 60 or 70 mm refractors would probably test
> > > > > > > > > > out fairly well. It's too bad that they don't gather all
> > > > > > > > > > that much light.
> > > > > > > > > He says it in one review, "small lenses are easy to make
> > > > > > > > > good." But there were surprises, like an 8 inch achromatic
> > > > > > > > > refractor objective (2400mm focal length) from China off
> > > > > > > > > Ebay that scored well.
> > > > > > > > > But some of the "sacred cows" of the scope world (Intes
> > > > > > > > > Micro maks) didn't score well. There is another site
> > > > > > > > > (German) that does similar stuff.
> > > > > > > > >
> > > > > > > > > http://astro-foren.com/index.php/de/schwerpunkt
> > > > > > > > Are these telescopes truly random samples or just ones that
> > > > > > > > the owners suspect are defective?
> > > > > > > Random, people just interested. I doubt someone sent in a TEC
> > > > > > > 160 with the idea it was defective.
> > > > > > The fact that someone brought in a $12K OTA has no relevance
> > > > > > whatsoever to my question. All the other tested scopes that were
> > > > > > 1/3 wave or worse are bound to seem lacking compared to any
> > > > > > similar examples that seem sharper in real life. If your $400
> > > > > > OTA gives good images you probably won't waste time testing it.
> > > > > Unless you are curious and someone offers.
> > > > That's not relevant.
> > > >
> > > > Are the tested telescopes representative of each of the telescope
> > > > models?
> > > > Are the tested telescopes representative of the population of
> > > > telescopes as a whole?
> > > >
> > > > If either of the above are not the case, then this exercise is
> > > > pointless, except to the individual owner who might be inspired to
> > > > return a telescope that he already thought was defective.
> > > I would say, given the mass production of scopes today, whatever is
> > > tested is likely representative of what you might buy. I once tested
> > > 32 Meade ETX-90 telescopes in a row (took five hours) and you really
> > > could see no noticeable difference between them. Such is the case
> > > >with computerized, mass-production.
> > //
> >
> > What were the P/V, RMS and Strehl results on those ETX-90s?
> >
> > There were no ETX-90s in the link you gave. I have not heard anything
> > bad about the optics in those; they seem to give Questars a run for the
> > money, considering the price difference. There were some 125s in there,
> > two "bad" and one great. Maybe those two were not representative.
> No, no ETX 90s in the test. I do believe there are bad ETX125s just like
> the Intes Maks in tests. There was a natural connection to worse tests for
> larger scopes, which makes sense. Though a considerably larger scope has
> to be pretty bad to not "beat" a good smaller scope >on planets or deepsky
> objects.

I tallied up the results for all of the examples of a particular telescope
model that enjoys a good reputation. Half were good, a few were so-so and a
couple of them looked bad, based on the numbers. If 25% of them were
sub-par, then the rep of the model would not be that good. I have to
conclude that the tested telescopes are not representative of their
respective types and models. The site does show that bad examples of some
models are possible and that maybe good examples exist too. That isn't news.

Maybe ETX90s are rare in Russia. Maybe ETX90s have such good QC that owners
have no reason to want to test them. The same lack of curiosity could apply
to the owners of many individual telescopes, even if a few of those types or
models have some number of dogs among them.

That old Sky and Telescope article wherein 1- , 1/2, 1/4, 1/10-wave
telescopes were tested side-by-side under the night sky should shed some
light on this. The 1-wave and 1/2-wave telescopes were easy to identify. The
1/4 and 1/10-wave telescopes were more difficult to distinguish from each
other.